Major reorg

draw/README.md

@@ -5,7 +5,7 @@ Clay UI integration.
 
 ## Current state
 
-The renderer uses a single unified `Pipeline_2D_Base` (`TRIANGLELIST` pipeline) with two submission
+The renderer uses a single unified `Core_2D` (`TRIANGLELIST` pipeline) with two submission
 modes dispatched by a push constant:
 
 - **Mode 0 (Tessellated):** Vertex buffer contains real geometry. Used for text (indexed draws into
@@ -15,10 +15,10 @@ modes dispatched by a push constant:
   shader premultiplies the texture sample (`t.rgb *= t.a`) and computes `out = color * t`.
 
 - **Mode 1 (SDF):** A static 6-vertex unit-quad buffer is drawn instanced, with per-primitive
-  `Base_2D_Primitive` structs (96 bytes each) uploaded each frame to a GPU storage buffer. The vertex
+  `Core_2D_Primitive` structs (96 bytes each) uploaded each frame to a GPU storage buffer. The vertex
   shader reads `primitives[gl_InstanceIndex]`, computes world-space position from unit quad corners +
   primitive bounds. The fragment shader dispatches on `Shape_Kind` (encoded in the low byte of
-  `Base_2D_Primitive.flags`) to evaluate one of four signed distance functions:
+  `Core_2D_Primitive.flags`) to evaluate one of four signed distance functions:
   - **RRect** (kind 1) — `sdRoundedBox` with per-corner radii. Covers rectangles (sharp or rounded),
     circles (uniform radii = half-size), and line segments / capsules (rotated RRect with uniform
     radii = half-thickness). Covers filled, outlined, textured, and gradient-filled variants.
@@ -28,9 +28,9 @@ modes dispatched by a push constant:
     normals. Covers full rings, partial arcs, and pie slices (`inner_radius = 0`).
 
 All SDF shapes support fill, outline, solid color, 2-color linear gradients, 2-color radial
-gradients, and texture fills via `Shape_Flags` (see `pipeline_2d_base.odin`). The texture UV rect
+gradients, and texture fills via `Shape_Flags` (see `core_2d.odin`). The texture UV rect
 (`uv_rect: [4]f32`) and the gradient/outline parameters (`effects: Gradient_Outline`) live in their
-own 16-byte slots in `Base_2D_Primitive`, so a primitive can carry texture and outline simultaneously.
+own 16-byte slots in `Core_2D_Primitive`, so a primitive can carry texture and outline simultaneously.
 Gradient and texture remain mutually exclusive at the fill-source level (a Brush variant chooses one
 or the other) since they share the worst-case fragment-shader register path.
 
@@ -433,19 +433,19 @@ our design:
 ### Main pipeline: SDF + tessellated (unified)
 
 The main pipeline serves two submission modes through a single `TRIANGLELIST` pipeline and a single
-vertex input layout, distinguished by a `mode` field in the `Vertex_Uniforms` push constant
+vertex input layout, distinguished by a `mode` field in the `Vertex_Uniforms_2D` push constant
-(`Draw_Mode.Tessellated = 0`, `Draw_Mode.SDF = 1`), pushed per draw call via `push_globals`. The
+(`Core_2D_Mode.Tessellated = 0`, `Core_2D_Mode.SDF = 1`), pushed per draw call via `push_globals`. The
 vertex shader branches on this uniform to select the tessellated or SDF code path.
 
 - **Tessellated mode** (`mode = 0`): direct vertex buffer with explicit geometry. Used for text
   (SDL_ttf atlas sampling), triangles, triangle fans/strips, single-pixel points, and any
   user-provided raw vertex geometry.
 - **SDF mode** (`mode = 1`): shared unit-quad vertex buffer + GPU storage buffer of
-  `Base_2D_Primitive` structs, drawn instanced. Used for all shapes with closed-form signed distance
+  `Core_2D_Primitive` structs, drawn instanced. Used for all shapes with closed-form signed distance
   functions.
 
 Both modes use the same fragment shader. The fragment shader checks `Shape_Kind` (low byte of
-`Base_2D_Primitive.flags`): kind 0 (`Solid`) is the tessellated path, which premultiplies the texture
+`Core_2D_Primitive.flags`): kind 0 (`Solid`) is the tessellated path, which premultiplies the texture
 sample and computes `out = color * t`; kinds 1–4 dispatch to one of four SDF functions (RRect, NGon,
 Ellipse, Ring_Arc) and apply gradient/texture/outline/solid color based on `Shape_Flags` bits.
 
@@ -454,7 +454,7 @@ Ellipse, Ring_Arc) and apply gradient/texture/outline/solid color based on `Shap
 CPU-side adaptive tessellation for curved shapes (the current approach) has three problems:
 
 1. **Vertex bandwidth.** A rounded rectangle with four corner arcs produces ~250 vertices × 20 bytes
-   = 5 KB. An SDF rounded rectangle is one `Base_2D_Primitive` struct (96 bytes) plus 4 shared
+   = 5 KB. An SDF rounded rectangle is one `Core_2D_Primitive` struct (96 bytes) plus 4 shared
    unit-quad vertices. That is roughly a 50× reduction per shape.
 
 2. **Quality.** Tessellated curves are piecewise-linear approximations. At high DPI or under
@@ -486,7 +486,7 @@ SDF primitives are submitted via a GPU storage buffer indexed by `gl_InstanceInd
 shader, rather than encoding per-primitive data redundantly in vertex attributes. This follows the
 pattern used by both Zed GPUI and vger-rs.
 
-Each SDF shape is described by a single `Base_2D_Primitive` struct (96 bytes) in the storage
+Each SDF shape is described by a single `Core_2D_Primitive` struct (96 bytes) in the storage
 buffer. The vertex shader reads `primitives[gl_InstanceIndex]`, computes the quad corner position
 from the unit vertex and the primitive's bounds, and passes shape parameters to the fragment shader
 via `flat` interpolated varyings.
@@ -501,10 +501,10 @@ in a draw call has the same mode — so it is effectively free on all modern GPU
 
 #### Shape kinds and SDF dispatch
 
-The fragment shader dispatches on `Shape_Kind` (low byte of `Base_2D_Primitive.flags`) to evaluate
+The fragment shader dispatches on `Shape_Kind` (low byte of `Core_2D_Primitive.flags`) to evaluate
-one of four signed distance functions. The `Shape_Kind` enum and per-kind `*_Params` structs are
+one of four signed distance functions. The `Shape_Kind` enum, per-kind `*_Params` structs, and
-defined in `pipeline_2d_base.odin`. CPU-side drawing procs in `shapes.odin` build the appropriate
+CPU-side drawing procs all live in `core_2d.odin`. The drawing procs build the appropriate
-`Base_2D_Primitive` and set the kind automatically:
+`Core_2D_Primitive` and set the kind automatically:
 
 Each user-facing shape proc accepts a `Brush` union (color, linear gradient, radial gradient,
 or textured fill) as its fill source, plus optional outline parameters. The procs map to SDF
@@ -522,7 +522,7 @@ kinds as follows:
 | `ring` (pie slice)   | `Ring_Arc` | Annular radial SDF | `inner_radius = 0`, angular clipping via `start/end_angle` |
 
 The `Shape_Flags` bit set controls per-primitive rendering mode (outline, gradient, texture, rotation,
-arc geometry). See the `Shape_Flag` enum in `pipeline_2d_base.odin` for the authoritative flag
+arc geometry). See the `Shape_Flag` enum in `core_2d.odin` for the authoritative flag
 definitions and bit assignments.
 
 **What stays tessellated:**
@@ -662,7 +662,7 @@ for the factor-selection table and rationale).
 #### Submission-order trade-off
 
 Within Pass A and Pass B, sub-batches render in the user's submission order. What the bracket model
-sacrifices is *interleaved* ordering between backdrop and non-backdrop content within a single
+sacrifices is _interleaved_ ordering between backdrop and non-backdrop content within a single
 layer. A non-backdrop sub-batch submitted between two backdrops still renders in Pass B (after the
 bracket), not at its submission position. Worked example:
 
@@ -675,7 +675,7 @@ draw.gaussian_blur(layer, panelB, sigma=12)     // 4  Backdrop     → Bracket
 draw.text(layer, "label", ...)                  // 5  Text         → Pass B   (drawn ON TOP of both panels)
 ```
 
-In this layer, panelB does *not* see card_red — even though card_red was submitted before panelB —
+In this layer, panelB does _not_ see card_red — even though card_red was submitted before panelB —
 because both backdrops sample `source_texture` as it stood at the bracket entry, which is after
 Pass A and before card_red has rendered. card_red ends up on top of panelA, not underneath it.
 
@@ -709,7 +709,7 @@ abstraction. This matches the cost/complexity envelope of iOS `UIVisualEffectVie
 The vertex struct is unchanged from the current 20-byte layout:
 
 ```
-Vertex :: struct {
+Vertex_2D :: struct {
     position: [2]f32,  //  0: screen-space position
     uv:       [2]f32,  //  8: atlas UV (text) or unused (shapes)
     color:    Color,   // 16: u8x4, GPU-normalized to float
@@ -721,10 +721,10 @@ draws, `position` carries actual world-space geometry. For SDF draws, `position`
 corners (0,0 to 1,1) and the vertex shader computes world-space position from the storage-buffer
 primitive's bounds.
 
-The `Base_2D_Primitive` struct for SDF shapes lives in the storage buffer, not in vertex attributes:
+The `Core_2D_Primitive` struct for SDF shapes lives in the storage buffer, not in vertex attributes:
 
 ```
-Base_2D_Primitive :: struct {
+Core_2D_Primitive :: struct {
     bounds:      [4]f32,           //  0: min_x, min_y, max_x, max_y
     color:       Color,            // 16: u8x4, unpacked in shader via unpackUnorm4x8
     flags:       u32,              // 20: low byte = Shape_Kind, bits 8+ = Shape_Flags
@@ -738,7 +738,7 @@ Base_2D_Primitive :: struct {
 ```
 
 `Shape_Params` is a `#raw_union` over `RRect_Params`, `NGon_Params`, `Ellipse_Params`, and
-`Ring_Arc_Params` (plus a `raw: [8]f32` view), defined in `pipeline_2d_base.odin`. Each SDF kind
+`Ring_Arc_Params` (plus a `raw: [8]f32` view), defined in `core_2d.odin`. Each SDF kind
 writes its own params variant; the fragment shader reads the appropriate fields based on `Shape_Kind`.
 `Gradient_Outline` is a 16-byte struct containing `gradient_color: Color`, `outline_color: Color`,
 `gradient_dir_sc: u32` (packed f16 cos/sin pair), and `outline_packed: u32` (packed f16 outline

draw/backdrop.odin

@@ -5,151 +5,79 @@ import "core:math"
 import "core:mem"
 import sdl "vendor:sdl3"
 
-// Adaptive downsample design (Flutter-style).
+// This file hosts the backdrop subsystem: any visual effect that samples the current
+// framebuffer as input. Today the only implemented effect is Gaussian blur (frosted glass);
+// future effects (refraction, mirror, etc.) will live here too.
 //
-// The bracket picks a downsample factor per-sigma-group, not as a global constant. The choice
+// The file is split into two top-level sections:
-// is driven by Flutter's `CalculateScale` formula in
-// impeller/entity/contents/filters/gaussian_blur_filter_contents.cc (originally from Skia's
-// GrBlurUtils): downsample so that the sigma in working-resolution pixels stays in the
-// 2..4 range. This keeps the kernel reach wide enough to hide high-frequency artifacts from
-// the bilinear upsample at the composite, while keeping the kernel's discrete tap count
-// small (≤3σ reach → ≈12 paired taps).
 //
-// The full table, in physical pixels (sigma_logical * dpi_scaling):
+//   1. Shared backdrop infrastructure — bracket coordination, source_texture lifecycle,
+//      sub-batch scanners. These are general to any backdrop effect: every backdrop effect
+//      needs a snapshot of the framebuffer (source_texture) and needs to participate in the
+//      bracket render-pass-boundary scheduling. When a second effect is added, its
+//      per-effect resources go in their own section like the Gaussian blur one below; this
+//      shared section stays.
 //
-//   sigma_phys ≤ 4    → factor = 1   (no downsample; source is sampled directly)
+//   2. Gaussian blur — the only effect implemented today. Owns its own PSOs, working
-//   sigma_phys ≤ 8    → factor = 2
+//      textures (downsample / h_blur), per-primitive storage layout, kernel math, and
-//   sigma_phys >  8   → factor = 4   (capped)
+//      bracket-runner inner loop. None of this is shared with future backdrop effects: a
+//      refraction shader would have its own PSO, its own primitive struct, and likely
+//      wouldn't need the downsample/h_blur intermediates at all.
 //
-// Capped at factor=4 to favor visual quality over bandwidth at the high end. Larger factors
+// The `Backdrop` struct currently holds resources from both categories; field-group
-// (8 and 16) would lose more high-frequency detail than the kernel can mask even with the
+// comments inside it mark which are which. When a second effect lands the struct will be
-// H+V split, and the bandwidth saving is small (the work region also shrinks quadratically,
+// split, but doing that pre-emptively means inventing a per-effect dispatch protocol on
-// so most of the savings are already captured at factor=4).
+// speculation. Better to keep the conflation visible (and labeled) until concrete needs
-//
+// shape the design.
-// Working textures are sized at full swapchain resolution to support factor=1. Larger factors
-// just write to a smaller sub-rect via viewport-limited rendering. Memory cost: full-res
-// working textures (2 textures, RGBA8) is roughly 16 MB at 1080p, 64 MB at 4K. On modern
-// GPUs this is well within budget; on Mali Valhall SBCs it's negligible against unified-
-// memory headroom.
-//
-// The shaders read the factor as a uniform. The downsample shader has three paths (factor=1
-// identity, factor=2 single bilinear tap, factor>=4 four bilinear taps with offsets scaling
-// by factor/4). The V-composite mode of backdrop_blur.frag uses inv_downsample_factor to
-// scale full-res frag coords down to working-res UV.
-
-// Maximum number of (weight, offset) pairs in a single blur kernel. Each pair represents
-// the linear-sampling pair adjustment (one bilinear fetch covering two adjacent texels);
-// pair[0] is the center weight with offset 0. With 32 pairs we cover up to 63 input texels
-// (1 center + 31 paired symmetric taps × 2 texels each), enough for sigma values well past
-// the 4..24 typical UI range. Must match MAX_KERNEL_PAIRS in shaders/source/backdrop_blur.frag.
-MAX_BACKDROP_KERNEL_PAIRS :: 32
-
-// Backdrop_Primitive is the GPU-side per-primitive storage layout. Mirrors the GLSL std430
-// struct in shaders/source/backdrop_blur.vert. Field order is chosen so std430 alignment
-// rules pack the struct to a clean 48-byte natural layout (no implicit padding): vec4
-// members come first (16-byte aligned at any offset), then vec2, then scalars. The total is
-// a multiple of 16 so the std430 array stride matches size_of(...) exactly.
-//
-// Backdrop primitives are RRect-only: rectangles, rounded rectangles, and circles
-// (via uniform_radii) are all expressible. Rotation is intentionally omitted — backdrop
-// sampling is in screen space, so a rotated mask over a stationary blur sample would look
-// visually wrong. iOS, CSS backdrop-filter, and Flutter BackdropFilter all enforce this
-// implicitly; we enforce it explicitly by leaving no rotation field.
-//
-// Outline is also intentionally omitted. A specialized edge effect (e.g. liquid-glass-style
-// refraction outlines) would be implemented as a dedicated primitive type with its own
-// pipeline rather than tacked onto this one as a flag bit.
-Backdrop_Primitive :: struct {
-	bounds:       [4]f32, //  0: 16 — world-space quad (min_xy, max_xy)
-	radii:        [4]f32, // 16: 16 — per-corner radii in physical pixels (BR, TR, BL, TL)
-	half_size:    [2]f32, // 32:  8 — RRect half extents (physical px)
-	half_feather: f32, // 40:  4 — feather_px * 0.5 (SDF anti-aliasing)
-	color:        Color, // 44:  4 — tint, packed RGBA u8x4
-}
-#assert(size_of(Backdrop_Primitive) == 48)
 
 // ---------------------------------------------------------------------------------------------------------------------
-// ----- Uniform blocks ----------------
+// ----- Shared backdrop infrastructure ------------
 // ---------------------------------------------------------------------------------------------------------------------
 
-// Vertex uniforms for the unified blur PSO (mode 0 = H-blur, mode 1 = V-composite).
+//INTERNAL
-// Matches the GLSL Uniforms block in shaders/source/backdrop_blur.vert. The downsample
+Backdrop :: struct {
-// PSO has no vertex uniforms.
+	// -- Shared across all backdrop effects --
-Backdrop_Vert_Uniforms :: struct {
-	projection: matrix[4, 4]f32, //  0: 64 — screen-space ortho (mode 1 only; mode 0 ignores)
-	dpi_scale:  f32, // 64:  4
-	mode:       u32, // 68:  4 — 0 = H-blur fullscreen tri; 1 = V-composite instanced quads
-	_pad0:      [2]f32, // 72:  8 — std140 vec4 alignment pad
-}
 
-// Fragment uniforms for the downsample PSO. Matches Uniforms block in
+	// When any backdrop draw exists this frame, the entire frame renders into source_texture
-// shaders/source/backdrop_downsample.frag.
+	// instead of the swapchain. Acts as the bracket's snapshot input by virtue of already
-Backdrop_Downsample_Frag_Uniforms :: struct {
+	// containing the pre-bracket frame. Copied to the swapchain at frame end.
-	inv_source_size:   [2]f32, //  0:  8 — 1.0 / source_texture pixel dimensions (full-res)
+	source_texture:      ^sdl.GPUTexture,
-	downsample_factor: u32, //  8:  4 — 1, 2, or 4 (selects identity / 1-tap / 4-tap path in shader)
-	_pad0:             u32, // 12:  4
-}
 
-// Fragment uniforms for the unified blur PSO (mode 0 + mode 1). Matches the GLSL Uniforms
+	// Cached pixel dimensions for resize-detection in `ensure_backdrop_textures`.
-// block in shaders/source/backdrop_blur.frag. The kernel array holds the linear-sampling
+	cached_width:        u32,
-// pair coefficients computed CPU-side via `compute_blur_kernel`.
+	cached_height:       u32,
-Backdrop_Frag_Uniforms :: struct {
-	inv_working_size:      [2]f32, //  0:   8 — 1.0 / working-resolution texture dimensions
-	pair_count:            u32, //  8:   4 — number of (weight, offset) pairs; pair[0] is center
-	mode:                  u32, // 12:   4 — 0 = H-blur, 1 = V-composite (must match vert mode)
-	direction:             [2]f32, // 16:   8 — (1,0) for H-blur, (0,1) for V-composite
-	inv_downsample_factor: f32, // 24:   4 — 1.0 / downsample_factor (mode 1 only; mode 0 ignores)
-	_pad0:                 f32, // 28:   4
-	kernel:                [MAX_BACKDROP_KERNEL_PAIRS][4]f32, // 32: 512 — .x = weight, .y = offset (texels)
-}
 
-// ---------------------------------------------------------------------------------------------------------------------
+	// Linear-clamp sampler used for sampling source_texture (and Gaussian blur's working
-// ----- Pipeline ---------------
+	// textures). Linear filtering is required by the Gaussian linear-sampling pair trick;
-// ---------------------------------------------------------------------------------------------------------------------
+	// any future backdrop effect that samples source_texture with bilinear interpolation
+	// can reuse this sampler. Clamp avoids edge-bleed at work-region boundaries.
+	sampler:             ^sdl.GPUSampler,
+
+	// -- Gaussian blur effect --
 
-Pipeline_2D_Backdrop :: struct {
 	// Two graphics pipelines. The downsample PSO is a single-bilinear-sample fullscreen pass;
 	// the blur PSO is mode-branched (H-blur fullscreen + V-composite instanced) and shares
 	// one shader program for both modes via a uniform `mode` selector.
 	downsample_pipeline: ^sdl.GPUGraphicsPipeline,
 	blur_pipeline:       ^sdl.GPUGraphicsPipeline,
 
-	// Per-instance Backdrop_Primitive storage buffer. Grows on demand via grow_buffer_if_needed.
+	// Per-instance Gaussian_Blur_Primitive storage buffer. Grows on demand via grow_buffer_if_needed.
 	// All backdrop primitives across all layers in a frame share this single buffer; sub-batches
 	// reference into it by offset.
 	primitive_buffer:    Buffer,
 
 	// Working textures, allocated once at swapchain resolution and recreated only on resize.
-	// All three are sized at full swapchain resolution and single-sample. Larger downsample
+	// Both are sized at full swapchain resolution and single-sample. Larger downsample
-	// factors fill only a sub-rect via viewport-limited rendering (see file-header comment).
+	// factors fill only a sub-rect via viewport-limited rendering (see file-header comment
-	//   source_texture     — when any backdrop draw exists this frame, the entire frame renders
+	// on adaptive downsampling in the Gaussian blur section below).
-	//                         here instead of the swapchain. Copied to the swapchain at frame
-	//                         end. Acts as the bracket's snapshot input by virtue of already
-	//                         containing the pre-bracket frame.
 	//   downsample_texture — written by the downsample PSO. Read by the blur PSO in mode 0.
 	//   h_blur_texture     — written by the blur PSO in mode 0. Read by the blur PSO in mode 1.
-	source_texture:      ^sdl.GPUTexture,
 	downsample_texture:  ^sdl.GPUTexture,
 	h_blur_texture:      ^sdl.GPUTexture,
-
-	// Cached pixel dimensions for resize-detection in `ensure_backdrop_textures`.
-	cached_width:        u32,
-	cached_height:       u32,
-
-	// Linear-clamp sampler used for all backdrop sampling. Linear filtering is required by the
-	// linear-sampling pair trick (one bilinear fetch covers two adjacent texels). Clamp avoids
-	// edge-bleed at the work-region boundary.
-	sampler:             ^sdl.GPUSampler,
 }
 
-@(private)
+//INTERNAL
-create_pipeline_2d_backdrop :: proc(
+create_backdrop :: proc(device: ^sdl.GPUDevice, window: ^sdl.Window) -> (pipeline: Backdrop, ok: bool) {
-	device: ^sdl.GPUDevice,
-	window: ^sdl.Window,
-) -> (
-	pipeline: Pipeline_2D_Backdrop,
-	ok: bool,
-) {
 	// On failure, clean up any partially-created resources.
 	defer if !ok {
 		if pipeline.sampler != nil do sdl.ReleaseGPUSampler(device, pipeline.sampler)
@@ -307,10 +235,10 @@ create_pipeline_2d_backdrop :: proc(
 		return pipeline, false
 	}
 
-	//----- Storage buffer for Backdrop_Primitive instances -------------
+	//----- Storage buffer for Gaussian_Blur_Primitive instances -------------
 	pipeline.primitive_buffer = create_buffer(
 		device,
-		size_of(Backdrop_Primitive) * BUFFER_INIT_SIZE,
+		size_of(Gaussian_Blur_Primitive) * BUFFER_INIT_SIZE,
 		sdl.GPUBufferUsageFlags{.GRAPHICS_STORAGE_READ},
 	) or_return
 
@@ -331,12 +259,12 @@ create_pipeline_2d_backdrop :: proc(
 		return pipeline, false
 	}
 
-	log.debug("Done creating backdrop pipeline")
+	log.debug("Done creating backdrop subsystem")
 	return pipeline, true
 }
 
-@(private)
+//INTERNAL
-destroy_pipeline_2d_backdrop :: proc(device: ^sdl.GPUDevice, pipeline: ^Pipeline_2D_Backdrop) {
+destroy_backdrop :: proc(device: ^sdl.GPUDevice, pipeline: ^Backdrop) {
 	if pipeline.h_blur_texture != nil do sdl.ReleaseGPUTexture(device, pipeline.h_blur_texture)
 	if pipeline.downsample_texture != nil do sdl.ReleaseGPUTexture(device, pipeline.downsample_texture)
 	if pipeline.source_texture != nil do sdl.ReleaseGPUTexture(device, pipeline.source_texture)
@@ -346,20 +274,22 @@ destroy_pipeline_2d_backdrop :: proc(device: ^sdl.GPUDevice, pipeline: ^Pipeline
 	if pipeline.downsample_pipeline != nil do sdl.ReleaseGPUGraphicsPipeline(device, pipeline.downsample_pipeline)
 }
 
-// ---------------------------------------------------------------------------------------------------------------------
+//----- Working texture management ----------------------------------
-// ----- Working texture management ----
-// ---------------------------------------------------------------------------------------------------------------------
 
 // Allocate (or reallocate, on resize) the three working textures that the backdrop bracket
 // uses. All three are sized at full swapchain resolution, single-sample, share the swapchain
 // format, and need {.COLOR_TARGET, .SAMPLER} usage so they can be written by render passes
 // and read by subsequent passes.
 //
+// `source_texture` is shared infrastructure (used by every backdrop effect).
+// `downsample_texture` and `h_blur_texture` are Gaussian-blur-specific intermediates; a
+// future backdrop effect with no downsample/blur prep would skip them.
+//
 // Recreates on dimension change only — same-size frames hit the early-out and skip GPU
 // resource churn.
-@(private)
+//INTERNAL
 ensure_backdrop_textures :: proc(device: ^sdl.GPUDevice, format: sdl.GPUTextureFormat, width, height: u32) {
-	pipeline := &GLOB.pipeline_2d_backdrop
+	pipeline := &GLOB.backdrop
 	if pipeline.source_texture != nil && pipeline.cached_width == width && pipeline.cached_height == height {
 		return
 	}
@@ -449,10 +379,138 @@ ensure_backdrop_textures :: proc(device: ^sdl.GPUDevice, format: sdl.GPUTextureF
 	pipeline.cached_height = height
 }
 
+//----- Frame / layer scanners ----------------------------------
+
+// Returns true if any sub-batch in any layer this frame is .Backdrop kind. Called once at the
+// top of `end()` to decide whether to route the whole frame to source_texture.
+// O(total sub-batches) but with an early-exit on the first hit, so typical cost is tiny.
+//INTERNAL
+frame_has_backdrop :: proc() -> bool {
+	for &batch in GLOB.tmp_sub_batches {
+		if batch.kind == .Backdrop do return true
+	}
+	return false
+}
+
+// Returns the absolute index of the first .Backdrop sub-batch in the layer's sub-batch range,
+// or -1 if the layer has no backdrops. The index is into GLOB.tmp_sub_batches (not relative to
+// layer.sub_batch_start), to match how draw_layer's render-range helpers consume it.
+//INTERNAL
+find_first_backdrop_in_layer :: proc(layer: ^Layer) -> int {
+	for i in 0 ..< layer.sub_batch_len {
+		abs_idx := layer.sub_batch_start + i
+		if GLOB.tmp_sub_batches[abs_idx].kind == .Backdrop do return int(abs_idx)
+	}
+	return -1
+}
+
 // ---------------------------------------------------------------------------------------------------------------------
-// ----- Kernel computation ------------
+// ----- Gaussian blur ------------
 // ---------------------------------------------------------------------------------------------------------------------
 
+// Adaptive downsample design (Flutter-style).
+//
+// The bracket picks a downsample factor per-sigma-group, not as a global constant. The choice
+// is driven by Flutter's `CalculateScale` formula in
+// impeller/entity/contents/filters/gaussian_blur_filter_contents.cc (originally from Skia's
+// GrBlurUtils): downsample so that the sigma in working-resolution pixels stays in the
+// 2..4 range. This keeps the kernel reach wide enough to hide high-frequency artifacts from
+// the bilinear upsample at the composite, while keeping the kernel's discrete tap count
+// small (≤3σ reach → ≈12 paired taps).
+//
+// The full table, in physical pixels (sigma_logical * dpi_scaling):
+//
+//   sigma_phys ≤ 4    → factor = 1   (no downsample; source is sampled directly)
+//   sigma_phys ≤ 8    → factor = 2
+//   sigma_phys >  8   → factor = 4   (capped)
+//
+// Capped at factor=4 to favor visual quality over bandwidth at the high end. Larger factors
+// (8 and 16) would lose more high-frequency detail than the kernel can mask even with the
+// H+V split, and the bandwidth saving is small (the work region also shrinks quadratically,
+// so most of the savings are already captured at factor=4).
+//
+// Working textures are sized at full swapchain resolution to support factor=1. Larger factors
+// just write to a smaller sub-rect via viewport-limited rendering. Memory cost: full-res
+// working textures (2 textures, RGBA8) is roughly 16 MB at 1080p, 64 MB at 4K. On modern
+// GPUs this is well within budget; on Mali Valhall SBCs it's negligible against unified-
+// memory headroom.
+//
+// The shaders read the factor as a uniform. The downsample shader has three paths (factor=1
+// identity, factor=2 single bilinear tap, factor>=4 four bilinear taps with offsets scaling
+// by factor/4). The V-composite mode of backdrop_blur.frag uses inv_downsample_factor to
+// scale full-res frag coords down to working-res UV.
+
+//----- GPU types ----------------------------------
+
+// Maximum number of (weight, offset) pairs in a single blur kernel. Each pair represents
+// the linear-sampling pair adjustment (one bilinear fetch covering two adjacent texels);
+// pair[0] is the center weight with offset 0. With 32 pairs we cover up to 63 input texels
+// (1 center + 31 paired symmetric taps × 2 texels each), enough for sigma values well past
+// the 4..24 typical UI range. Must match MAX_KERNEL_PAIRS in shaders/source/backdrop_blur.frag.
+//INTERNAL
+MAX_GAUSSIAN_BLUR_KERNEL_PAIRS :: 32
+
+// Gaussian_Blur_Primitive is the GPU-side per-primitive storage layout. Mirrors the GLSL std430
+// struct in shaders/source/backdrop_blur.vert. Field order is chosen so std430 alignment
+// rules pack the struct to a clean 48-byte natural layout (no implicit padding): vec4
+// members come first (16-byte aligned at any offset), then vec2, then scalars. The total is
+// a multiple of 16 so the std430 array stride matches size_of(...) exactly.
+//
+// Gaussian blur primitives are RRect-only: rectangles, rounded rectangles, and circles
+// (via uniform_radii) are all expressible. Rotation is intentionally omitted — backdrop
+// sampling is in screen space, so a rotated mask over a stationary blur sample would look
+// visually wrong. iOS, CSS backdrop-filter, and Flutter BackdropFilter all enforce this
+// implicitly; we enforce it explicitly by leaving no rotation field.
+//
+// Outline is also intentionally omitted. A specialized edge effect (e.g. liquid-glass-style
+// refraction outlines) would be implemented as a dedicated primitive type with its own
+// pipeline rather than tacked onto this one as a flag bit.
+//INTERNAL
+Gaussian_Blur_Primitive :: struct {
+	bounds:       [4]f32, //  0: 16 — world-space quad (min_xy, max_xy)
+	radii:        [4]f32, // 16: 16 — per-corner radii in physical pixels (BR, TR, BL, TL)
+	half_size:    [2]f32, // 32:  8 — RRect half extents (physical px)
+	half_feather: f32, // 40:  4 — feather_px * 0.5 (SDF anti-aliasing)
+	color:        Color, // 44:  4 — tint, packed RGBA u8x4
+}
+#assert(size_of(Gaussian_Blur_Primitive) == 48)
+
+// Vertex uniforms for the unified blur PSO (mode 0 = H-blur, mode 1 = V-composite).
+// Matches the GLSL Uniforms block in shaders/source/backdrop_blur.vert. The downsample
+// PSO has no vertex uniforms.
+//INTERNAL
+Gaussian_Blur_Vert_Uniforms :: struct {
+	projection: matrix[4, 4]f32, //  0: 64 — screen-space ortho (mode 1 only; mode 0 ignores)
+	dpi_scale:  f32, // 64:  4
+	mode:       u32, // 68:  4 — 0 = H-blur fullscreen tri; 1 = V-composite instanced quads
+	_pad0:      [2]f32, // 72:  8 — std140 vec4 alignment pad
+}
+
+// Fragment uniforms for the downsample PSO. Matches Uniforms block in
+// shaders/source/backdrop_downsample.frag.
+//INTERNAL
+Gaussian_Blur_Downsample_Frag_Uniforms :: struct {
+	inv_source_size:   [2]f32, //  0:  8 — 1.0 / source_texture pixel dimensions (full-res)
+	downsample_factor: u32, //  8:  4 — 1, 2, or 4 (selects identity / 1-tap / 4-tap path in shader)
+	_pad0:             u32, // 12:  4
+}
+
+// Fragment uniforms for the unified blur PSO (mode 0 + mode 1). Matches the GLSL Uniforms
+// block in shaders/source/backdrop_blur.frag. The kernel array holds the linear-sampling
+// pair coefficients computed CPU-side via `compute_blur_kernel`.
+//INTERNAL
+Gaussian_Blur_Frag_Uniforms :: struct {
+	inv_working_size:      [2]f32, //  0:   8 — 1.0 / working-resolution texture dimensions
+	pair_count:            u32, //  8:   4 — number of (weight, offset) pairs; pair[0] is center
+	mode:                  u32, // 12:   4 — 0 = H-blur, 1 = V-composite (must match vert mode)
+	direction:             [2]f32, // 16:   8 — (1,0) for H-blur, (0,1) for V-composite
+	inv_downsample_factor: f32, // 24:   4 — 1.0 / downsample_factor (mode 1 only; mode 0 ignores)
+	_pad0:                 f32, // 28:   4
+	kernel:                [MAX_GAUSSIAN_BLUR_KERNEL_PAIRS][4]f32, // 32: 512 — .x = weight, .y = offset (texels)
+}
+
+//----- Kernel computation ----------------------------------
+
 // Compute Gaussian blur kernel weights with the linear-sampling pair adjustment.
 // Adapted from RAD Debugger's r_d3d11_g_blur_shader_src CPU-side coefficient generation
 // and Daniel Rákos's "Efficient Gaussian blur with linear sampling" article.
@@ -480,18 +538,23 @@ ensure_backdrop_textures :: proc(device: ^sdl.GPUDevice, format: sdl.GPUTextureF
 // from it, rather than the inverse (RAD Debugger's algorithm passes a tap count and derives
 // `stdev = (blur_count-1)/2`). Taking σ directly matches what callers expect when they read
 // "gaussian_sigma" — passing tap count under that name was a footgun.
-@(private)
+//INTERNAL
-compute_blur_kernel :: proc(sigma: f32, kernel: ^[MAX_BACKDROP_KERNEL_PAIRS][4]f32) -> (pair_count: u32) {
+compute_blur_kernel :: proc(
+	sigma: f32,
+	kernel: ^[MAX_GAUSSIAN_BLUR_KERNEL_PAIRS][4]f32,
+) -> (
+	pair_count: u32,
+) {
 	if sigma <= 0 {
 		kernel[0] = {1, 0, 0, 0}
 		return 1
 	}
 
 	// Per-side discrete tap count: ceil(3*sigma) + 1 (center + 3σ reach on each side).
-	// Cap at the storage budget. With MAX_BACKDROP_KERNEL_PAIRS=32 each pair collapses 2
+	// Cap at the storage budget. With MAX_GAUSSIAN_BLUR_KERNEL_PAIRS=32 each pair collapses 2
 	// discrete taps via linear-sampling, so max discrete taps per side = 1 + 31*2 = 63.
 	discrete_taps := u32(math.ceil(3 * sigma)) + 1
-	max_taps := u32(MAX_BACKDROP_KERNEL_PAIRS - 1) * 2 + 1
+	max_taps := u32(MAX_GAUSSIAN_BLUR_KERNEL_PAIRS - 1) * 2 + 1
 	if discrete_taps > max_taps do discrete_taps = max_taps
 	if discrete_taps < 2 {
 		// Sigma was so small that 3σ < 1 texel; degenerate to a sharp sample.
@@ -501,7 +564,7 @@ compute_blur_kernel :: proc(sigma: f32, kernel: ^[MAX_BACKDROP_KERNEL_PAIRS][4]f
 
 	// Compute discrete weights[i] = exp(-i² / (2σ²)). The inv_root prefactor cancels in the
 	// final normalization, so we skip it.
-	weights: [MAX_BACKDROP_KERNEL_PAIRS * 2]f32 = {}
+	weights: [MAX_GAUSSIAN_BLUR_KERNEL_PAIRS * 2]f32 = {}
 	two_sigma_sq := 2 * sigma * sigma
 	total: f32 = 0
 	for i in 0 ..< discrete_taps {
@@ -535,38 +598,9 @@ compute_blur_kernel :: proc(sigma: f32, kernel: ^[MAX_BACKDROP_KERNEL_PAIRS][4]f
 	return pair_count
 }
 
-// ---------------------------------------------------------------------------------------------------------------------
-// ----- Uniform push helpers ----------
-// ---------------------------------------------------------------------------------------------------------------------
-
-// Push the Backdrop_Vert_Uniforms block to the vertex stage at slot 0.
-@(private)
-push_backdrop_vert_globals :: proc(cmd_buffer: ^sdl.GPUCommandBuffer, width: f32, height: f32, mode: u32) {
-	uniforms := Backdrop_Vert_Uniforms {
-		projection = ortho_rh(left = 0.0, top = 0.0, right = width, bottom = height, near = -1.0, far = 1.0),
-		dpi_scale  = GLOB.dpi_scaling,
-		mode       = mode,
-	}
-	sdl.PushGPUVertexUniformData(cmd_buffer, 0, &uniforms, size_of(Backdrop_Vert_Uniforms))
-}
-
-// Push the Backdrop_Downsample_Frag_Uniforms block to the fragment stage at slot 0.
-@(private)
-push_backdrop_downsample_frag_globals :: proc(
-	cmd_buffer: ^sdl.GPUCommandBuffer,
-	source_width, source_height: u32,
-	downsample_factor: u32,
-) {
-	uniforms := Backdrop_Downsample_Frag_Uniforms {
-		inv_source_size   = {1.0 / f32(source_width), 1.0 / f32(source_height)},
-		downsample_factor = downsample_factor,
-	}
-	sdl.PushGPUFragmentUniformData(cmd_buffer, 0, &uniforms, size_of(Backdrop_Downsample_Frag_Uniforms))
-}
-
 // Pick a downsample factor for a given sigma. See the file-header comment for the table and
 // rationale. Returned values: {1, 2, 4}.
-@(private)
+//INTERNAL
 compute_backdrop_downsample_factor :: proc(sigma_logical: f32) -> u32 {
 	sigma_phys := sigma_logical * GLOB.dpi_scaling
 	switch {
@@ -576,80 +610,76 @@ compute_backdrop_downsample_factor :: proc(sigma_logical: f32) -> u32 {
 	}
 }
 
-// Push the Backdrop_Frag_Uniforms block (kernel + pass mode/direction) to the fragment stage at slot 0.
+//----- Uniform push helpers ----------------------------------
-@(private)
+
-push_backdrop_blur_frag_globals :: proc(
+// Push the Gaussian_Blur_Vert_Uniforms block to the vertex stage at slot 0.
-	cmd_buffer: ^sdl.GPUCommandBuffer,
+//INTERNAL
-	uniforms: ^Backdrop_Frag_Uniforms,
+push_backdrop_vert_globals :: proc(cmd_buffer: ^sdl.GPUCommandBuffer, width: f32, height: f32, mode: u32) {
-) {
+	uniforms := Gaussian_Blur_Vert_Uniforms {
-	sdl.PushGPUFragmentUniformData(cmd_buffer, 0, uniforms, size_of(Backdrop_Frag_Uniforms))
+		projection = ortho_rh(left = 0.0, top = 0.0, right = width, bottom = height, near = -1.0, far = 1.0),
+		dpi_scale  = GLOB.dpi_scaling,
+		mode       = mode,
+	}
+	sdl.PushGPUVertexUniformData(cmd_buffer, 0, &uniforms, size_of(Gaussian_Blur_Vert_Uniforms))
 }
 
-// ---------------------------------------------------------------------------------------------------------------------
+// Push the Gaussian_Blur_Downsample_Frag_Uniforms block to the fragment stage at slot 0.
-// ----- Storage-buffer upload ---------
+//INTERNAL
-// ---------------------------------------------------------------------------------------------------------------------
+push_backdrop_downsample_frag_globals :: proc(
+	cmd_buffer: ^sdl.GPUCommandBuffer,
+	source_width, source_height: u32,
+	downsample_factor: u32,
+) {
+	uniforms := Gaussian_Blur_Downsample_Frag_Uniforms {
+		inv_source_size   = {1.0 / f32(source_width), 1.0 / f32(source_height)},
+		downsample_factor = downsample_factor,
+	}
+	sdl.PushGPUFragmentUniformData(cmd_buffer, 0, &uniforms, size_of(Gaussian_Blur_Downsample_Frag_Uniforms))
+}
 
-// Upload all Backdrop_Primitive instances staged this frame to the backdrop pipeline's storage
+// Push the Gaussian_Blur_Frag_Uniforms block (kernel + pass mode/direction) to the fragment stage at slot 0.
-// buffer. Mirrors the SDF primitive upload in pipeline_2d_base.odin's `upload`. Called from
+//INTERNAL
+push_backdrop_blur_frag_globals :: proc(
+	cmd_buffer: ^sdl.GPUCommandBuffer,
+	uniforms: ^Gaussian_Blur_Frag_Uniforms,
+) {
+	sdl.PushGPUFragmentUniformData(cmd_buffer, 0, uniforms, size_of(Gaussian_Blur_Frag_Uniforms))
+}
+
+//----- Storage-buffer upload ----------------------------------
+
+// Upload all Gaussian_Blur_Primitive instances staged this frame to the backdrop subsystem's storage
+// buffer. Mirrors the SDF primitive upload in core_2d.odin's `upload`. Called from
 // `end()` inside the same copy pass that uploads vertices/indices/SDF primitives.
-@(private)
+//INTERNAL
 upload_backdrop_primitives :: proc(device: ^sdl.GPUDevice, pass: ^sdl.GPUCopyPass) {
-	prim_count := u32(len(GLOB.tmp_backdrop_primitives))
+	prim_count := u32(len(GLOB.tmp_gaussian_blur_primitives))
 	if prim_count == 0 do return
 
-	prim_size := prim_count * size_of(Backdrop_Primitive)
+	prim_size := prim_count * size_of(Gaussian_Blur_Primitive)
 	grow_buffer_if_needed(
 		device,
-		&GLOB.pipeline_2d_backdrop.primitive_buffer,
+		&GLOB.backdrop.primitive_buffer,
 		prim_size,
 		sdl.GPUBufferUsageFlags{.GRAPHICS_STORAGE_READ},
 	)
 
-	prim_array := sdl.MapGPUTransferBuffer(device, GLOB.pipeline_2d_backdrop.primitive_buffer.transfer, false)
+	prim_array := sdl.MapGPUTransferBuffer(device, GLOB.backdrop.primitive_buffer.transfer, false)
 	if prim_array == nil {
 		log.panicf("Failed to map backdrop primitive transfer buffer: %s", sdl.GetError())
 	}
-	mem.copy(prim_array, raw_data(GLOB.tmp_backdrop_primitives), int(prim_size))
+	mem.copy(prim_array, raw_data(GLOB.tmp_gaussian_blur_primitives), int(prim_size))
-	sdl.UnmapGPUTransferBuffer(device, GLOB.pipeline_2d_backdrop.primitive_buffer.transfer)
+	sdl.UnmapGPUTransferBuffer(device, GLOB.backdrop.primitive_buffer.transfer)
 
 	sdl.UploadToGPUBuffer(
 		pass,
-		sdl.GPUTransferBufferLocation{transfer_buffer = GLOB.pipeline_2d_backdrop.primitive_buffer.transfer},
+		sdl.GPUTransferBufferLocation{transfer_buffer = GLOB.backdrop.primitive_buffer.transfer},
-		sdl.GPUBufferRegion{buffer = GLOB.pipeline_2d_backdrop.primitive_buffer.gpu, offset = 0, size = prim_size},
+		sdl.GPUBufferRegion{buffer = GLOB.backdrop.primitive_buffer.gpu, offset = 0, size = prim_size},
 		false,
 	)
 }
 
-// ---------------------------------------------------------------------------------------------------------------------
+//----- Bracket scheduler ----------------------------------
-// ----- Frame / layer scanners --------
-// ---------------------------------------------------------------------------------------------------------------------
-
-// Returns true if any sub-batch in any layer this frame is .Backdrop kind. Called once at the
-// top of `end()` to decide whether to route the whole frame to source_texture.
-// O(total sub-batches) but with an early-exit on the first hit, so typical cost is tiny.
-@(private)
-frame_has_backdrop :: proc() -> bool {
-	for &batch in GLOB.tmp_sub_batches {
-		if batch.kind == .Backdrop do return true
-	}
-	return false
-}
-
-// Returns the absolute index of the first .Backdrop sub-batch in the layer's sub-batch range,
-// or -1 if the layer has no backdrops. The index is into GLOB.tmp_sub_batches (not relative to
-// layer.sub_batch_start), to match how draw_layer's render-range helpers consume it.
-@(private)
-find_first_backdrop_in_layer :: proc(layer: ^Layer) -> int {
-	for i in 0 ..< layer.sub_batch_len {
-		abs_idx := layer.sub_batch_start + i
-		if GLOB.tmp_sub_batches[abs_idx].kind == .Backdrop do return int(abs_idx)
-	}
-	return -1
-}
-
-// ---------------------------------------------------------------------------------------------------------------------
-// ----- Bracket scheduler -------------
-// ---------------------------------------------------------------------------------------------------------------------
 
 // Compute the union AABB of the backdrop primitives in a contiguous-same-sigma sub-batch run
 // (one "sigma group"), expanded by 6 sigmas of blur reach (the kernel weight beyond 3σ is
@@ -661,7 +691,7 @@ find_first_backdrop_in_layer :: proc(layer: ^Layer) -> int {
 // Per-group (rather than per-layer) because the adaptive downsample picks a different factor
 // per sigma, and the kernel reach is also per-sigma. A tighter region per group means less
 // fragment work in the downsample and H-blur passes.
-@(private)
+//INTERNAL
 compute_backdrop_group_work_region :: proc(
 	group_start, group_end: u32,
 	sigma_logical: f32,
@@ -680,7 +710,7 @@ compute_backdrop_group_work_region :: proc(
 		batch := GLOB.tmp_sub_batches[i]
 		if batch.kind != .Backdrop do continue
 		for p in batch.offset ..< batch.offset + batch.count {
-			prim := GLOB.tmp_backdrop_primitives[p]
+			prim := GLOB.tmp_gaussian_blur_primitives[p]
 			// prim.bounds is in logical pixels (world space).
 			if !has_any {
 				min_x = prim.bounds[0]
@@ -751,13 +781,13 @@ compute_backdrop_group_work_region :: proc(
 // On exit, source_texture contains the pre-bracket contents plus all backdrop primitives
 // composited on top. The caller then runs Pass B (post-bracket non-backdrop sub-batches) on
 // source_texture with LOAD.
-@(private)
+//INTERNAL
 run_backdrop_bracket :: proc(
 	cmd_buffer: ^sdl.GPUCommandBuffer,
 	layer: ^Layer,
 	swapchain_width, swapchain_height: u32,
 ) {
-	pipeline := &GLOB.pipeline_2d_backdrop
+	pipeline := &GLOB.backdrop
 
 	full_viewport := sdl.GPUViewport {
 		x         = 0,
@@ -852,7 +882,7 @@ run_backdrop_bracket :: proc(
 		// Convert the user's logical-pixel sigma into the kernel's working space.
 		// sigma_working_texels = sigma_logical * dpi_scaling / downsample_factor.
 		effective_sigma := sigma * GLOB.dpi_scaling / f32(downsample_factor)
-		frag_uniforms := Backdrop_Frag_Uniforms {
+		frag_uniforms := Gaussian_Blur_Frag_Uniforms {
 			inv_working_size      = inv_working_size,
 			inv_downsample_factor = 1.0 / f32(downsample_factor),
 		}
@@ -1002,24 +1032,20 @@ run_backdrop_bracket :: proc(
 	}
 }
 
-// ---------------------------------------------------------------------------------------------------------------------
+//----- Primitive builders ----------------------------------
-// ----- Primitive builders ------------
-// ---------------------------------------------------------------------------------------------------------------------
 
-// Internal
+// Build a Gaussian_Blur_Primitive with bounds, radii, and feather computed from rectangle
-//
-// Build a Backdrop_Primitive with bounds, radii, and feather computed from rectangle
 // geometry. The caller sets `color` (tint) on the returned primitive before submitting.
 //
-// No rotation, no outline — backdrop primitives are intentionally limited to axis-aligned
+// No rotation, no outline — gaussian blur primitives are intentionally limited to axis-aligned
 // RRects. Rotation breaks screen-space blur sampling visually; outline would be a specialized
 // edge effect that belongs in its own primitive type.
-@(private)
+//INTERNAL
 build_backdrop_primitive :: proc(
 	rect: Rectangle,
 	radii: Rectangle_Radii,
 	feather_px: f32,
-) -> Backdrop_Primitive {
+) -> Gaussian_Blur_Primitive {
 	max_radius := min(rect.width, rect.height) * 0.5
 	clamped_top_left := clamp(radii.top_left, 0, max_radius)
 	clamped_top_right := clamp(radii.top_right, 0, max_radius)
@@ -1035,7 +1061,7 @@ build_backdrop_primitive :: proc(
 	center_x := rect.x + half_width
 	center_y := rect.y + half_height
 
-	return Backdrop_Primitive {
+	return Gaussian_Blur_Primitive {
 		bounds       = {
 			center_x - half_width - padding,
 			center_y - half_height - padding,
@@ -1057,13 +1083,13 @@ build_backdrop_primitive :: proc(
 	}
 }
 
-// Internal — append a Backdrop_Primitive to the staging array and emit a .Backdrop sub-batch
+// Append a Gaussian_Blur_Primitive to the staging array and emit a .Backdrop sub-batch
 // carrying the requested gaussian_sigma. Sub-batch coalescing in append_or_extend_sub_batch
 // will merge contiguous backdrops that share a sigma into a single instanced draw.
-@(private)
+//INTERNAL
-prepare_backdrop_primitive :: proc(layer: ^Layer, prim: Backdrop_Primitive, gaussian_sigma: f32) {
+prepare_backdrop_primitive :: proc(layer: ^Layer, prim: Gaussian_Blur_Primitive, gaussian_sigma: f32) {
-	offset := u32(len(GLOB.tmp_backdrop_primitives))
+	offset := u32(len(GLOB.tmp_gaussian_blur_primitives))
-	append(&GLOB.tmp_backdrop_primitives, prim)
+	append(&GLOB.tmp_gaussian_blur_primitives, prim)
 	scissor := &GLOB.scissors[layer.scissor_start + layer.scissor_len - 1]
 	append_or_extend_sub_batch(
 		scissor,
@@ -1075,9 +1101,7 @@ prepare_backdrop_primitive :: proc(layer: ^Layer, prim: Backdrop_Primitive, gaus
 	)
 }
 
-// ---------------------------------------------------------------------------------------------------------------------
+//----- Public API ----------------------------------
-// ----- Public API --------------------
-// ---------------------------------------------------------------------------------------------------------------------
 
 // Draw a rectangle whose interior samples a Gaussian-blurred snapshot of the framebuffer
 // behind it. RRect-only — covers rectangles, rounded rectangles, and circles via

draw/draw.odin

@@ -10,6 +10,11 @@ import sdl_ttf "vendor:sdl3/ttf"
 
 import clay "../vendor/clay"
 
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Shader format ------------
+// ---------------------------------------------------------------------------------------------------------------------
+
+//INTERNAL (each constant in the when-block below)
 when ODIN_OS == .Darwin {
 	PLATFORM_SHADER_FORMAT_FLAG :: sdl.GPUShaderFormatFlag.MSL
 	SHADER_ENTRY :: cstring("main0")
@@ -29,10 +34,18 @@ when ODIN_OS == .Darwin {
 	BACKDROP_BLUR_VERT_RAW :: #load("shaders/generated/backdrop_blur.vert.spv")
 	BACKDROP_BLUR_FRAG_RAW :: #load("shaders/generated/backdrop_blur.frag.spv")
 }
+
 PLATFORM_SHADER_FORMAT :: sdl.GPUShaderFormat{PLATFORM_SHADER_FORMAT_FLAG}
 
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Defaults and config ------------
+// ---------------------------------------------------------------------------------------------------------------------
+
+//INTERNAL
 BUFFER_INIT_SIZE :: 256
+//INTERNAL
 INITIAL_LAYER_SIZE :: 5
+//INTERNAL
 INITIAL_SCISSOR_SIZE :: 10
 
 // ----- Default parameter values -----
@@ -48,64 +61,70 @@ DFT_TEXT_COLOR :: BLACK // Default text color.
 DFT_CLEAR_COLOR :: BLACK // Default clear color for end().
 DFT_SAMPLER :: Sampler_Preset.Linear_Clamp // Default texture sampler preset.
 
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Global state ------------
+// ---------------------------------------------------------------------------------------------------------------------
+
+//INTERNAL
 GLOB: Global
 
+//INTERNAL
 Global :: struct {
 	// -- Per-frame staging (hottest — touched by every prepare/upload/clear cycle) --
-	tmp_shape_verts:          [dynamic]Vertex, // Tessellated shape vertices staged for GPU upload.
+	tmp_shape_verts:              [dynamic]Vertex_2D, // Tessellated shape vertices staged for GPU upload.
-	tmp_text_verts:           [dynamic]Vertex, // Text vertices staged for GPU upload.
+	tmp_text_verts:               [dynamic]Vertex_2D, // Text vertices staged for GPU upload.
-	tmp_text_indices:         [dynamic]c.int, // Text index buffer staged for GPU upload.
+	tmp_text_indices:             [dynamic]c.int, // Text index buffer staged for GPU upload.
-	tmp_text_batches:         [dynamic]TextBatch, // Text atlas batch metadata for indexed drawing.
+	tmp_text_batches:             [dynamic]Text_Batch, // Text atlas batch metadata for indexed drawing.
-	tmp_primitives:           [dynamic]Base_2D_Primitive, // SDF primitives staged for GPU storage buffer upload (base 2D pipeline).
+	tmp_primitives:               [dynamic]Core_2D_Primitive, // SDF primitives staged for GPU storage buffer upload (core 2D subsystem).
-	tmp_sub_batches:          [dynamic]Sub_Batch, // Sub-batch records that drive draw call dispatch.
+	tmp_sub_batches:              [dynamic]Sub_Batch, // Sub-batch records that drive draw call dispatch.
-	tmp_uncached_text:        [dynamic]^sdl_ttf.Text, // Uncached TTF_Text objects destroyed after end() submits.
+	tmp_uncached_text:            [dynamic]^sdl_ttf.Text, // Uncached TTF_Text objects destroyed after end() submits.
-	tmp_backdrop_primitives:  [dynamic]Backdrop_Primitive, // Backdrop primitives staged for GPU storage buffer upload.
+	tmp_gaussian_blur_primitives: [dynamic]Gaussian_Blur_Primitive, // Gaussian blur primitives staged for GPU storage buffer upload.
-	layers:                   [dynamic]Layer, // Draw layers, each with its own scissor stack.
+	layers:                       [dynamic]Layer, // Draw layers, each with its own scissor stack.
-	scissors:                 [dynamic]Scissor, // Scissor rects that clip drawing within each layer.
+	scissors:                     [dynamic]Scissor, // Scissor rects that clip drawing within each layer.
 
 	// -- Per-frame scalars (accessed during prepare and draw_layer) --
-	curr_layer_index:         uint, // Index of the currently active layer.
+	curr_layer_index:             uint, // Index of the currently active layer.
-	dpi_scaling:              f32, // Window DPI scale factor applied to all pixel coordinates.
+	dpi_scaling:                  f32, // Window DPI scale factor applied to all pixel coordinates.
-	clay_z_index:             i16, // Tracks z-index for layer splitting during Clay batch processing.
+	clay_z_index:                 i16, // Tracks z-index for layer splitting during Clay batch processing.
-	cleared:                  bool, // Whether the render target has been cleared this frame.
+	cleared:                      bool, // Whether the render target has been cleared this frame.
 
-	// -- Pipeline (accessed every draw_layer call) --
+	// -- Subsystems (accessed every draw_layer call) --
-	pipeline_2d_base:         Pipeline_2D_Base, // The unified 2D GPU pipeline (shaders, buffers, samplers).
+	core_2d:                      Core_2D, // The unified 2D GPU pipeline (shaders, buffers, samplers).
-	pipeline_2d_backdrop:     Pipeline_2D_Backdrop, // Frosted-glass backdrop blur pipeline (downsample + blur PSOs, working textures).
+	backdrop:                     Backdrop, // Frosted-glass backdrop blur subsystem (downsample + blur PSOs, working textures).
-	device:                   ^sdl.GPUDevice, // GPU device handle, stored at init.
+	device:                       ^sdl.GPUDevice, // GPU device handle, stored at init.
-	samplers:                 [SAMPLER_PRESET_COUNT]^sdl.GPUSampler, // Lazily-created sampler objects, one per Sampler_Preset.
+	samplers:                     [SAMPLER_PRESET_COUNT]^sdl.GPUSampler, // Lazily-created sampler objects, one per Sampler_Preset.
 
 	// -- Deferred release (processed once per frame at frame boundary) --
-	pending_texture_releases: [dynamic]Texture_Id, // Deferred GPU texture releases, processed next frame.
+	pending_texture_releases:     [dynamic]Texture_Id, // Deferred GPU texture releases, processed next frame.
-	pending_text_releases:    [dynamic]^sdl_ttf.Text, // Deferred TTF_Text destroys, processed next frame.
+	pending_text_releases:        [dynamic]^sdl_ttf.Text, // Deferred TTF_Text destroys, processed next frame.
 
 	// -- Textures (registration is occasional, binding is per draw call) --
-	texture_slots:            [dynamic]Texture_Slot, // Registered texture slots indexed by Texture_Id.
+	texture_slots:                [dynamic]Texture_Slot, // Registered texture slots indexed by Texture_Id.
-	texture_free_list:        [dynamic]u32, // Recycled slot indices available for reuse.
+	texture_free_list:            [dynamic]u32, // Recycled slot indices available for reuse.
 
 	// -- Clay (once per frame in prepare_clay_batch) --
-	clay_memory:              [^]u8, // Raw memory block backing Clay's internal arena.
+	clay_memory:                  [^]u8, // Raw memory block backing Clay's internal arena.
 
 	// -- Text (occasional — font registration and text cache lookups) --
-	text_cache:               Text_Cache, // Font registry, SDL_ttf engine, and cached TTF_Text objects.
+	text_cache:                   Text_Cache, // Font registry, SDL_ttf engine, and cached TTF_Text objects.
 
 	// -- Resize tracking (cold — checked once per frame in resize_global) --
-	max_layers:               int, // High-water marks for dynamic array shrink heuristic.
+	max_layers:                   int, // High-water marks for dynamic array shrink heuristic.
-	max_scissors:             int,
+	max_scissors:                 int,
-	max_shape_verts:          int,
+	max_shape_verts:              int,
-	max_text_verts:           int,
+	max_text_verts:               int,
-	max_text_indices:         int,
+	max_text_indices:             int,
-	max_text_batches:         int,
+	max_text_batches:             int,
-	max_primitives:           int,
+	max_primitives:               int,
-	max_sub_batches:          int,
+	max_sub_batches:              int,
-	max_backdrop_primitives:  int,
+	max_gaussian_blur_primitives: int,
 
 	// -- Init-only (coldest — set once at init, never written again) --
-	odin_context:             runtime.Context, // Odin context captured at init for use in callbacks.
+	odin_context:                 runtime.Context, // Odin context captured at init for use in callbacks.
 }
 
 // ---------------------------------------------------------------------------------------------------------------------
-// ----- Core types --------------------
+// ----- Core types ------------
 // ---------------------------------------------------------------------------------------------------------------------
 
 // A 2D position in world space. Non-distinct alias for [2]f32 — bare literals like {100, 200}
@@ -128,7 +147,7 @@ Vec2 :: [2]f32
 // transparent. This matches the GPU-side layout: the shader unpacks via unpackUnorm4x8 which
 // reads the bytes in memory order as R, G, B, A and normalizes each to [0, 1].
 //
-// When used in the Base_2D_Primitive or Backdrop_Primitive structs (e.g. .color), the 4 bytes
+// When used in the Core_2D_Primitive or Gaussian_Blur_Primitive structs (e.g. .color), the 4 bytes
 // are stored as a u32 in native byte order and unpacked by the shader.
 Color :: [4]u8
 
@@ -139,6 +158,13 @@ GREEN :: Color{0, 255, 0, 255}
 BLUE :: Color{0, 0, 255, 255}
 BLANK :: Color{0, 0, 0, 0}
 
+Rectangle :: struct {
+	x:      f32,
+	y:      f32,
+	width:  f32,
+	height: f32,
+}
+
 // Per-corner rounding radii for rectangles, specified clockwise from top-left.
 // All values are in logical pixels (pre-DPI-scaling).
 Rectangle_Radii :: struct {
@@ -201,7 +227,7 @@ color_to_f32 :: proc(color: Color) -> [4]f32 {
 // Pre-multiply RGB channels by alpha. The tessellated vertex path and text path require
 // premultiplied colors because the blend state is ONE, ONE_MINUS_SRC_ALPHA and the
 // tessellated fragment shader passes vertex color through without further modification.
-// Users who construct Vertex structs manually for prepare_shape must premultiply their colors.
+// Users who construct Vertex_2D structs manually for prepare_shape must premultiply their colors.
 premultiply_color :: #force_inline proc(color: Color) -> Color {
 	a := u32(color[3])
 	return Color {
@@ -212,22 +238,21 @@ premultiply_color :: #force_inline proc(color: Color) -> Color {
 	}
 }
 
-Rectangle :: struct {
+// ---------------------------------------------------------------------------------------------------------------------
-	x:      f32,
+// ----- Frame layout types ------------
-	y:      f32,
+// ---------------------------------------------------------------------------------------------------------------------
-	width:  f32,
-	height: f32,
-}
 
+//INTERNAL
 Sub_Batch_Kind :: enum u8 {
-	Tessellated, // non-indexed, white texture or user texture, base 2D mode 0
+	Tessellated, // non-indexed, white texture or user texture, Core_2D_Mode.Tessellated
-	Text, // indexed, atlas texture, base 2D mode 0
+	Text, // indexed, atlas texture, Core_2D_Mode.Tessellated
-	SDF, // instanced unit quad, base 2D mode 1
+	SDF, // instanced unit quad, Core_2D_Mode.SDF
-	// instanced unit quad, backdrop pipeline V-composite (indexes Backdrop_Primitive).
+	// instanced unit quad, backdrop subsystem V-composite (indexes Gaussian_Blur_Primitive).
 	// Bracket-scheduled per layer; see README.md § "Backdrop pipeline" for ordering semantics.
 	Backdrop,
 }
 
+//INTERNAL
 Sub_Batch :: struct {
 	kind:           Sub_Batch_Kind,
 	offset:         u32, // Tessellated: vertex offset; Text: text_batch index; SDF/Backdrop: primitive index
@@ -248,12 +273,17 @@ Layer :: struct {
 	scissor_len:     u32,
 }
 
+//INTERNAL
 Scissor :: struct {
 	bounds:          sdl.Rect,
 	sub_batch_start: u32,
 	sub_batch_len:   u32,
 }
 
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Lifecycle ------------
+// ---------------------------------------------------------------------------------------------------------------------
+
 // Initialize the renderer. Returns false if GPU pipeline or text engine creation fails.
 //
 // MSAA is intentionally NOT supported. SDF text and shapes compute coverage analytically via
@@ -272,46 +302,56 @@ init :: proc(
 ) {
 	min_memory_size: c.size_t = cast(c.size_t)clay.MinMemorySize()
 
-	pipeline, pipeline_ok := create_pipeline_2d_base(device, window)
+	core, core_ok := create_core_2d(device, window)
-	if !pipeline_ok {
+	if !core_ok {
 		return false
 	}
 
-	backdrop_pipeline, backdrop_pipeline_ok := create_pipeline_2d_backdrop(device, window)
+	backdrop, backdrop_ok := create_backdrop(device, window)
-	if !backdrop_pipeline_ok {
+	if !backdrop_ok {
-		destroy_pipeline_2d_base(device, &pipeline)
+		destroy_core_2d(device, &core)
 		return false
 	}
 
 	text_cache, text_ok := init_text_cache(device, allocator)
 	if !text_ok {
-		destroy_pipeline_2d_backdrop(device, &backdrop_pipeline)
+		destroy_backdrop(device, &backdrop)
-		destroy_pipeline_2d_base(device, &pipeline)
+		destroy_core_2d(device, &core)
 		return false
 	}
 
 	GLOB = Global {
-		layers                   = make([dynamic]Layer, 0, INITIAL_LAYER_SIZE, allocator = allocator),
+		layers                       = make([dynamic]Layer, 0, INITIAL_LAYER_SIZE, allocator = allocator),
-		scissors                 = make([dynamic]Scissor, 0, INITIAL_SCISSOR_SIZE, allocator = allocator),
+		scissors                     = make([dynamic]Scissor, 0, INITIAL_SCISSOR_SIZE, allocator = allocator),
-		tmp_shape_verts          = make([dynamic]Vertex, 0, BUFFER_INIT_SIZE, allocator = allocator),
+		tmp_shape_verts              = make([dynamic]Vertex_2D, 0, BUFFER_INIT_SIZE, allocator = allocator),
-		tmp_text_verts           = make([dynamic]Vertex, 0, BUFFER_INIT_SIZE, allocator = allocator),
+		tmp_text_verts               = make([dynamic]Vertex_2D, 0, BUFFER_INIT_SIZE, allocator = allocator),
-		tmp_text_indices         = make([dynamic]c.int, 0, BUFFER_INIT_SIZE, allocator = allocator),
+		tmp_text_indices             = make([dynamic]c.int, 0, BUFFER_INIT_SIZE, allocator = allocator),
-		tmp_text_batches         = make([dynamic]TextBatch, 0, BUFFER_INIT_SIZE, allocator = allocator),
+		tmp_text_batches             = make([dynamic]Text_Batch, 0, BUFFER_INIT_SIZE, allocator = allocator),
-		tmp_primitives           = make([dynamic]Base_2D_Primitive, 0, BUFFER_INIT_SIZE, allocator = allocator),
+		tmp_primitives               = make(
-		tmp_sub_batches          = make([dynamic]Sub_Batch, 0, BUFFER_INIT_SIZE, allocator = allocator),
+			[dynamic]Core_2D_Primitive,
-		tmp_uncached_text        = make([dynamic]^sdl_ttf.Text, 0, 16, allocator = allocator),
+			0,
-		tmp_backdrop_primitives  = make([dynamic]Backdrop_Primitive, 0, BUFFER_INIT_SIZE, allocator = allocator),
+			BUFFER_INIT_SIZE,
-		device                   = device,
+			allocator = allocator,
-		texture_slots            = make([dynamic]Texture_Slot, 0, 16, allocator = allocator),
+		),
-		texture_free_list        = make([dynamic]u32, 0, 16, allocator = allocator),
+		tmp_sub_batches              = make([dynamic]Sub_Batch, 0, BUFFER_INIT_SIZE, allocator = allocator),
-		pending_texture_releases = make([dynamic]Texture_Id, 0, 16, allocator = allocator),
+		tmp_uncached_text            = make([dynamic]^sdl_ttf.Text, 0, 16, allocator = allocator),
-		pending_text_releases    = make([dynamic]^sdl_ttf.Text, 0, 16, allocator = allocator),
+		tmp_gaussian_blur_primitives = make(
-		odin_context             = odin_context,
+			[dynamic]Gaussian_Blur_Primitive,
-		dpi_scaling              = sdl.GetWindowDisplayScale(window),
+			0,
-		clay_memory              = make([^]u8, min_memory_size, allocator = allocator),
+			BUFFER_INIT_SIZE,
-		pipeline_2d_base         = pipeline,
+			allocator = allocator,
-		pipeline_2d_backdrop     = backdrop_pipeline,
+		),
-		text_cache               = text_cache,
+		device                       = device,
+		texture_slots                = make([dynamic]Texture_Slot, 0, 16, allocator = allocator),
+		texture_free_list            = make([dynamic]u32, 0, 16, allocator = allocator),
+		pending_texture_releases     = make([dynamic]Texture_Id, 0, 16, allocator = allocator),
+		pending_text_releases        = make([dynamic]^sdl_ttf.Text, 0, 16, allocator = allocator),
+		odin_context                 = odin_context,
+		dpi_scaling                  = sdl.GetWindowDisplayScale(window),
+		clay_memory                  = make([^]u8, min_memory_size, allocator = allocator),
+		core_2d                      = core,
+		backdrop                     = backdrop,
+		text_cache                   = text_cache,
 	}
 
 	// Reserve slot 0 for INVALID_TEXTURE
@@ -345,8 +385,8 @@ resize_global :: proc() {
 	shrink(&GLOB.tmp_primitives, GLOB.max_primitives)
 	if len(GLOB.tmp_sub_batches) > GLOB.max_sub_batches do GLOB.max_sub_batches = len(GLOB.tmp_sub_batches)
 	shrink(&GLOB.tmp_sub_batches, GLOB.max_sub_batches)
-	if len(GLOB.tmp_backdrop_primitives) > GLOB.max_backdrop_primitives do GLOB.max_backdrop_primitives = len(GLOB.tmp_backdrop_primitives)
+	if len(GLOB.tmp_gaussian_blur_primitives) > GLOB.max_gaussian_blur_primitives do GLOB.max_gaussian_blur_primitives = len(GLOB.tmp_gaussian_blur_primitives)
-	shrink(&GLOB.tmp_backdrop_primitives, GLOB.max_backdrop_primitives)
+	shrink(&GLOB.tmp_gaussian_blur_primitives, GLOB.max_gaussian_blur_primitives)
 }
 
 destroy :: proc(device: ^sdl.GPUDevice, allocator := context.allocator) {
@@ -358,7 +398,7 @@ destroy :: proc(device: ^sdl.GPUDevice, allocator := context.allocator) {
 	delete(GLOB.tmp_text_batches)
 	delete(GLOB.tmp_primitives)
 	delete(GLOB.tmp_sub_batches)
-	delete(GLOB.tmp_backdrop_primitives)
+	delete(GLOB.tmp_gaussian_blur_primitives)
 	for ttf_text in GLOB.tmp_uncached_text do sdl_ttf.DestroyText(ttf_text)
 	delete(GLOB.tmp_uncached_text)
 	free(GLOB.clay_memory, allocator)
@@ -367,12 +407,12 @@ destroy :: proc(device: ^sdl.GPUDevice, allocator := context.allocator) {
 	destroy_sampler_pool()
 	for ttf_text in GLOB.pending_text_releases do sdl_ttf.DestroyText(ttf_text)
 	delete(GLOB.pending_text_releases)
-	destroy_pipeline_2d_backdrop(device, &GLOB.pipeline_2d_backdrop)
+	destroy_backdrop(device, &GLOB.backdrop)
-	destroy_pipeline_2d_base(device, &GLOB.pipeline_2d_base)
+	destroy_core_2d(device, &GLOB.core_2d)
 	destroy_text_cache()
 }
 
-// Internal
+//INTERNAL
 clear_global :: proc() {
 	// Process deferred texture releases from the previous frame
 	process_pending_texture_releases()
@@ -394,33 +434,11 @@ clear_global :: proc() {
 	clear(&GLOB.tmp_text_batches)
 	clear(&GLOB.tmp_primitives)
 	clear(&GLOB.tmp_sub_batches)
-	clear(&GLOB.tmp_backdrop_primitives)
+	clear(&GLOB.tmp_gaussian_blur_primitives)
 }
 
 // ---------------------------------------------------------------------------------------------------------------------
-// ----- Text measurement (Clay) -------
+// ----- Frame ------------
-// ---------------------------------------------------------------------------------------------------------------------
-
-@(private = "file")
-measure_text_clay :: proc "c" (
-	text: clay.StringSlice,
-	config: ^clay.TextElementConfig,
-	user_data: rawptr,
-) -> clay.Dimensions {
-	context = GLOB.odin_context
-	text := string(text.chars[:text.length])
-	c_text := strings.clone_to_cstring(text, context.temp_allocator)
-	defer delete(c_text, context.temp_allocator)
-	width, height: c.int
-	if !sdl_ttf.GetStringSize(get_font(config.fontId, config.fontSize), c_text, 0, &width, &height) {
-		log.panicf("Failed to measure text: %s", sdl.GetError())
-	}
-
-	return clay.Dimensions{width = f32(width) / GLOB.dpi_scaling, height = f32(height) / GLOB.dpi_scaling}
-}
-
-// ---------------------------------------------------------------------------------------------------------------------
-// ----- Frame lifecycle ---------------
 // ---------------------------------------------------------------------------------------------------------------------
 
 // Sets up renderer to begin upload to the GPU. Returns starting `Layer` to begin processing primitives for.
@@ -472,133 +490,89 @@ new_layer :: proc(prev_layer: ^Layer, bounds: Rectangle) -> ^Layer {
 	return &GLOB.layers[GLOB.curr_layer_index]
 }
 
-// ---------------------------------------------------------------------------------------------------------------------
+// Render primitives. clear_color is the background fill before any layers are drawn.
-// ----- Built-in primitive processing --
+end :: proc(device: ^sdl.GPUDevice, window: ^sdl.Window, clear_color: Color = DFT_CLEAR_COLOR) {
-// ---------------------------------------------------------------------------------------------------------------------
+	cmd_buffer := sdl.AcquireGPUCommandBuffer(device)
-
+	if cmd_buffer == nil {
-// Submit shape vertices (colored triangles) to the given layer for rendering.
+		log.panicf("Failed to acquire GPU command buffer: %s", sdl.GetError())
-// TODO: Should probably be renamed to better match tesselated naming conventions in the library.
-prepare_shape :: proc(layer: ^Layer, vertices: []Vertex) {
-	if len(vertices) == 0 do return
-	offset := u32(len(GLOB.tmp_shape_verts))
-	append(&GLOB.tmp_shape_verts, ..vertices)
-	scissor := &GLOB.scissors[layer.scissor_start + layer.scissor_len - 1]
-	append_or_extend_sub_batch(scissor, layer, .Tessellated, offset, u32(len(vertices)))
-}
-
-// Submit an SDF primitive to the given layer for rendering.
-prepare_sdf_primitive :: proc(layer: ^Layer, prim: Base_2D_Primitive) {
-	offset := u32(len(GLOB.tmp_primitives))
-	append(&GLOB.tmp_primitives, prim)
-	scissor := &GLOB.scissors[layer.scissor_start + layer.scissor_len - 1]
-	append_or_extend_sub_batch(scissor, layer, .SDF, offset, 1)
-}
-
-// Submit a text element to the given layer for rendering.
-// Copies SDL_ttf vertices directly (with baked position) and copies indices for indexed drawing.
-prepare_text :: proc(layer: ^Layer, text: Text) {
-	data := sdl_ttf.GetGPUTextDrawData(text.sdl_text)
-	if data == nil {
-		return // nil is normal for empty text
 	}
 
-	scissor := &GLOB.scissors[layer.scissor_start + layer.scissor_len - 1]
+	// Pre-scan: if any layer this frame has a backdrop sub-batch, route the entire frame to
+	// source_texture so the bracket can sample the pre-bracket framebuffer without a mid-
+	// frame texture copy. Frames without any backdrop hit the existing fast path and never
+	// touch the backdrop pipeline's working textures.
+	has_backdrop := frame_has_backdrop()
 
-	// Snap base position to integer physical pixels to avoid atlas sub-pixel
+	// Upload primitives to GPU (vertices, indices, SDF prims, and backdrop prims share one
-	// sampling blur (and the off-by-one bottom-row clip that comes with it).
+	// copy pass so we pay the BeginGPUCopyPass / EndGPUCopyPass cost once per frame).
-	base_x := math.round(text.position[0] * GLOB.dpi_scaling)
+	copy_pass := sdl.BeginGPUCopyPass(cmd_buffer)
-	base_y := math.round(text.position[1] * GLOB.dpi_scaling)
+	upload(device, copy_pass)
+	if has_backdrop {
+		upload_backdrop_primitives(device, copy_pass)
+	}
+	sdl.EndGPUCopyPass(copy_pass)
 
-	// Premultiply text color once — reused across all glyph vertices.
+	swapchain_texture: ^sdl.GPUTexture
-	pm_color := premultiply_color(text.color)
+	width, height: u32
+	if !sdl.WaitAndAcquireGPUSwapchainTexture(cmd_buffer, window, &swapchain_texture, &width, &height) {
+		log.panicf("Failed to acquire swapchain texture: %s", sdl.GetError())
+	}
 
-	for data != nil {
+	if swapchain_texture == nil {
-		vertex_start := u32(len(GLOB.tmp_text_verts))
+		// Window is minimized or not visible — submit and skip this frame
-		index_start := u32(len(GLOB.tmp_text_indices))
+		if !sdl.SubmitGPUCommandBuffer(cmd_buffer) {
-
+			log.panicf("Failed to submit GPU command buffer (minimized window): %s", sdl.GetError())
-		// Copy vertices with baked position offset
-		for i in 0 ..< data.num_vertices {
-			pos := data.xy[i]
-			uv := data.uv[i]
-			append(
-				&GLOB.tmp_text_verts,
-				Vertex{position = {pos.x + base_x, -pos.y + base_y}, uv = {uv.x, uv.y}, color = pm_color},
-			)
 		}
-
-		// Copy indices directly
-		append(&GLOB.tmp_text_indices, ..data.indices[:data.num_indices])
-
-		batch_idx := u32(len(GLOB.tmp_text_batches))
-		append(
-			&GLOB.tmp_text_batches,
-			TextBatch {
-				atlas_texture = data.atlas_texture,
-				vertex_start = vertex_start,
-				vertex_count = u32(data.num_vertices),
-				index_start = index_start,
-				index_count = u32(data.num_indices),
-			},
-		)
-
-		// Each atlas chunk is a separate sub-batch (different atlas textures can't coalesce)
-		append_or_extend_sub_batch(scissor, layer, .Text, batch_idx, 1)
-
-		data = data.next
-	}
-}
-
-// Submit a text element with a 2D affine transform applied to vertices.
-// Used by the high-level `text` proc when rotation or a non-zero origin is specified.
-// NOTE: xform must be in physical (DPI-scaled) pixel space — the caller pre-scales
-// pos and origin by GLOB.dpi_scaling before building the transform.
-prepare_text_transformed :: proc(layer: ^Layer, text: Text, transform: Transform_2D) {
-	data := sdl_ttf.GetGPUTextDrawData(text.sdl_text)
-	if data == nil {
 		return
 	}
 
-	scissor := &GLOB.scissors[layer.scissor_start + layer.scissor_len - 1]
+	render_texture := swapchain_texture
+	if has_backdrop {
+		ensure_backdrop_textures(device, sdl.GetGPUSwapchainTextureFormat(device, window), width, height)
+		render_texture = GLOB.backdrop.source_texture
+	}
 
-	// Premultiply text color once — reused across all glyph vertices.
+	// Premultiply clear color: the blend state is ONE, ONE_MINUS_SRC_ALPHA (premultiplied),
-	pm_color := premultiply_color(text.color)
+	// so the clear color must also be premultiplied for correct background compositing.
+	clear_color_straight := color_to_f32(clear_color)
+	clear_alpha := clear_color_straight[3]
+	clear_color_f32 := [4]f32 {
+		clear_color_straight[0] * clear_alpha,
+		clear_color_straight[1] * clear_alpha,
+		clear_color_straight[2] * clear_alpha,
+		clear_alpha,
+	}
 
-	for data != nil {
+	// Draw layers. One render pass per layer; sub-batches draw in submission order within each scissor.
-		vertex_start := u32(len(GLOB.tmp_text_verts))
+	for &layer, index in GLOB.layers {
-		index_start := u32(len(GLOB.tmp_text_indices))
+		draw_layer(device, window, cmd_buffer, render_texture, width, height, clear_color_f32, &layer)
+	}
 
-		for i in 0 ..< data.num_vertices {
+	// When we rendered into source_texture, copy it to the swapchain. Single
-			pos := data.xy[i]
+	// CopyGPUTextureToTexture call per frame, only when backdrop content was present.
-			uv := data.uv[i]
+	if has_backdrop {
-			// SDL_ttf gives glyph positions in physical pixels relative to text origin.
+		copy_pass := sdl.BeginGPUCopyPass(cmd_buffer)
-			// The transform is already in physical-pixel space (caller pre-scaled),
+		sdl.CopyGPUTextureToTexture(
-			// so we apply directly — no per-vertex DPI divide/multiply.
+			copy_pass,
-			append(
+			sdl.GPUTextureLocation{texture = GLOB.backdrop.source_texture},
-				&GLOB.tmp_text_verts,
+			sdl.GPUTextureLocation{texture = swapchain_texture},
-				Vertex{position = apply_transform(transform, {pos.x, -pos.y}), uv = {uv.x, uv.y}, color = pm_color},
+			width,
-			)
+			height,
-		}
+			1,
-
+			false,
-		append(&GLOB.tmp_text_indices, ..data.indices[:data.num_indices])
-
-		batch_idx := u32(len(GLOB.tmp_text_batches))
-		append(
-			&GLOB.tmp_text_batches,
-			TextBatch {
-				atlas_texture = data.atlas_texture,
-				vertex_start = vertex_start,
-				vertex_count = u32(data.num_vertices),
-				index_start = index_start,
-				index_count = u32(data.num_indices),
-			},
 		)
+		sdl.EndGPUCopyPass(copy_pass)
+	}
 
-		append_or_extend_sub_batch(scissor, layer, .Text, batch_idx, 1)
+	if !sdl.SubmitGPUCommandBuffer(cmd_buffer) {
-
+		log.panicf("Failed to submit GPU command buffer: %s", sdl.GetError())
-		data = data.next
 	}
 }
 
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Sub-batch dispatch ------------
+// ---------------------------------------------------------------------------------------------------------------------
+
 // Append a new sub-batch or extend the last one if same kind and contiguous.
 //
 // `gaussian_sigma` is only consulted for kind == .Backdrop; two .Backdrop sub-batches with
@@ -606,7 +580,7 @@ prepare_text_transformed :: proc(layer: ^Layer, text: Text, transform: Transform
 // bracket scheduler. Float equality is intentional — user-supplied literal sigmas (e.g.
 // `sigma = 12`) produce bit-identical floats, and the worst case for two sigmas that differ
 // only by a ulp is one extra pass pair (correct, just slightly suboptimal).
-@(private)
+//INTERNAL
 append_or_extend_sub_batch :: proc(
 	scissor: ^Scissor,
 	layer: ^Layer,
@@ -645,7 +619,7 @@ append_or_extend_sub_batch :: proc(
 }
 
 // ---------------------------------------------------------------------------------------------------------------------
-// ----- Clay ------------------------
+// ----- Clay ------------
 // ---------------------------------------------------------------------------------------------------------------------
 
 @(private = "file")
@@ -654,6 +628,24 @@ clay_error_handler :: proc "c" (errorData: clay.ErrorData) {
 	log.error("Clay error:", errorData.errorType, errorData.errorText)
 }
 
+@(private = "file")
+measure_text_clay :: proc "c" (
+	text: clay.StringSlice,
+	config: ^clay.TextElementConfig,
+	user_data: rawptr,
+) -> clay.Dimensions {
+	context = GLOB.odin_context
+	text := string(text.chars[:text.length])
+	c_text := strings.clone_to_cstring(text, context.temp_allocator)
+	defer delete(c_text, context.temp_allocator)
+	width, height: c.int
+	if !sdl_ttf.GetStringSize(get_font(config.fontId, config.fontSize), c_text, 0, &width, &height) {
+		log.panicf("Failed to measure text: %s", sdl.GetError())
+	}
+
+	return clay.Dimensions{width = f32(width) / GLOB.dpi_scaling, height = f32(height) / GLOB.dpi_scaling}
+}
+
 // Called for each Clay `RenderCommandType.Custom` render command that
 // `prepare_clay_batch` encounters.
 //
@@ -822,142 +814,18 @@ prepare_clay_batch :: proc(
 	}
 }
 
-// Render primitives. clear_color is the background fill before any layers are drawn.
-end :: proc(device: ^sdl.GPUDevice, window: ^sdl.Window, clear_color: Color = DFT_CLEAR_COLOR) {
-	cmd_buffer := sdl.AcquireGPUCommandBuffer(device)
-	if cmd_buffer == nil {
-		log.panicf("Failed to acquire GPU command buffer: %s", sdl.GetError())
-	}
-
-	// Pre-scan: if any layer this frame has a backdrop sub-batch, route the entire frame to
-	// source_texture so the bracket can sample the pre-bracket framebuffer without a mid-
-	// frame texture copy. Frames without any backdrop hit the existing fast path and never
-	// touch the backdrop pipeline's working textures.
-	has_backdrop := frame_has_backdrop()
-
-	// Upload primitives to GPU (vertices, indices, SDF prims, and backdrop prims share one
-	// copy pass so we pay the BeginGPUCopyPass / EndGPUCopyPass cost once per frame).
-	copy_pass := sdl.BeginGPUCopyPass(cmd_buffer)
-	upload(device, copy_pass)
-	if has_backdrop {
-		upload_backdrop_primitives(device, copy_pass)
-	}
-	sdl.EndGPUCopyPass(copy_pass)
-
-	swapchain_texture: ^sdl.GPUTexture
-	width, height: u32
-	if !sdl.WaitAndAcquireGPUSwapchainTexture(cmd_buffer, window, &swapchain_texture, &width, &height) {
-		log.panicf("Failed to acquire swapchain texture: %s", sdl.GetError())
-	}
-
-	if swapchain_texture == nil {
-		// Window is minimized or not visible — submit and skip this frame
-		if !sdl.SubmitGPUCommandBuffer(cmd_buffer) {
-			log.panicf("Failed to submit GPU command buffer (minimized window): %s", sdl.GetError())
-		}
-		return
-	}
-
-	render_texture := swapchain_texture
-	if has_backdrop {
-		ensure_backdrop_textures(device, sdl.GetGPUSwapchainTextureFormat(device, window), width, height)
-		render_texture = GLOB.pipeline_2d_backdrop.source_texture
-	}
-
-	// Premultiply clear color: the blend state is ONE, ONE_MINUS_SRC_ALPHA (premultiplied),
-	// so the clear color must also be premultiplied for correct background compositing.
-	clear_color_straight := color_to_f32(clear_color)
-	clear_alpha := clear_color_straight[3]
-	clear_color_f32 := [4]f32 {
-		clear_color_straight[0] * clear_alpha,
-		clear_color_straight[1] * clear_alpha,
-		clear_color_straight[2] * clear_alpha,
-		clear_alpha,
-	}
-
-	// Draw layers. One render pass per layer; sub-batches draw in submission order within each scissor.
-	for &layer, index in GLOB.layers {
-		draw_layer(device, window, cmd_buffer, render_texture, width, height, clear_color_f32, &layer)
-	}
-
-	// When we rendered into source_texture, copy it to the swapchain. Single
-	// CopyGPUTextureToTexture call per frame, only when backdrop content was present.
-	if has_backdrop {
-		copy_pass := sdl.BeginGPUCopyPass(cmd_buffer)
-		sdl.CopyGPUTextureToTexture(
-			copy_pass,
-			sdl.GPUTextureLocation{texture = GLOB.pipeline_2d_backdrop.source_texture},
-			sdl.GPUTextureLocation{texture = swapchain_texture},
-			width,
-			height,
-			1,
-			false,
-		)
-		sdl.EndGPUCopyPass(copy_pass)
-	}
-
-	if !sdl.SubmitGPUCommandBuffer(cmd_buffer) {
-		log.panicf("Failed to submit GPU command buffer: %s", sdl.GetError())
-	}
-}
-
 // ---------------------------------------------------------------------------------------------------------------------
-// ----- Utility -----------------------
+// ----- Buffer ------------
-// ---------------------------------------------------------------------------------------------------------------------
-
-ortho_rh :: proc(left: f32, right: f32, bottom: f32, top: f32, near: f32, far: f32) -> matrix[4, 4]f32 {
-	return matrix[4, 4]f32{
-		2.0 / (right - left), 0.0, 0.0, -(right + left) / (right - left),
-		0.0, 2.0 / (top - bottom), 0.0, -(top + bottom) / (top - bottom),
-		0.0, 0.0, -2.0 / (far - near), -(far + near) / (far - near),
-		0.0, 0.0, 0.0, 1.0,
-	}
-}
-
-Draw_Mode :: enum u32 {
-	Tessellated = 0,
-	SDF         = 1,
-}
-
-Vertex_Uniforms :: struct {
-	projection: matrix[4, 4]f32,
-	scale:      f32,
-	mode:       Draw_Mode,
-}
-
-// Push projection, dpi scale, and rendering mode as a single uniform block (slot 0).
-push_globals :: proc(
-	cmd_buffer: ^sdl.GPUCommandBuffer,
-	width: f32,
-	height: f32,
-	mode: Draw_Mode = .Tessellated,
-) {
-	globals := Vertex_Uniforms {
-		projection = ortho_rh(
-			left = 0.0,
-			top = 0.0,
-			right = f32(width),
-			bottom = f32(height),
-			near = -1.0,
-			far = 1.0,
-		),
-		scale      = GLOB.dpi_scaling,
-		mode       = mode,
-	}
-
-	sdl.PushGPUVertexUniformData(cmd_buffer, 0, &globals, size_of(Vertex_Uniforms))
-}
-
-// ---------------------------------------------------------------------------------------------------------------------
-// ----- Buffer ------------------------
 // ---------------------------------------------------------------------------------------------------------------------
 
+//INTERNAL
 Buffer :: struct {
 	gpu:      ^sdl.GPUBuffer,
 	transfer: ^sdl.GPUTransferBuffer,
 	size:     u32,
 }
 
+//INTERNAL
 @(require_results)
 create_buffer :: proc(
 	device: ^sdl.GPUDevice,
@@ -984,6 +852,7 @@ create_buffer :: proc(
 	return Buffer{gpu, transfer, size}, true
 }
 
+//INTERNAL
 grow_buffer_if_needed :: proc(
 	device: ^sdl.GPUDevice,
 	buffer: ^Buffer,
@@ -1008,15 +877,26 @@ grow_buffer_if_needed :: proc(
 	}
 }
 
+//INTERNAL
 destroy_buffer :: proc(device: ^sdl.GPUDevice, buffer: ^Buffer) {
 	sdl.ReleaseGPUBuffer(device, buffer.gpu)
 	sdl.ReleaseGPUTransferBuffer(device, buffer.transfer)
 }
 
 // ---------------------------------------------------------------------------------------------------------------------
-// ----- Transform ------------------------
+// ----- Math ------------
 // ---------------------------------------------------------------------------------------------------------------------
 
+//INTERNAL
+ortho_rh :: proc(left: f32, right: f32, bottom: f32, top: f32, near: f32, far: f32) -> matrix[4, 4]f32 {
+	return matrix[4, 4]f32{
+		2.0 / (right - left), 0.0, 0.0, -(right + left) / (right - left),
+		0.0, 2.0 / (top - bottom), 0.0, -(top + bottom) / (top - bottom),
+		0.0, 0.0, -2.0 / (far - near), -(far + near) / (far - near),
+		0.0, 0.0, 0.0, 1.0,
+	}
+}
+
 // 2x3 affine transform for 2D pivot-rotation.
 // Used internally by rotation-aware drawing procs.
 Transform_2D :: struct {
@@ -1078,9 +958,114 @@ needs_transform :: #force_inline proc(origin: Vec2, rotation: f32) -> bool {
 }
 
 // ---------------------------------------------------------------------------------------------------------------------
-// ----- Procedure Groups ------------------------
+// ----- Anchors ------------
 // ---------------------------------------------------------------------------------------------------------------------
 
+// Return Vec2 pixel offsets for use as the `origin` parameter of draw calls.
+// Composable with normal vector +/- arithmetic.
+//
+// Text anchor helpers are in text.odin (they depend on measure_text / SDL_ttf).
+
+// Returns uniform radii (all corners the same) as a fraction of the shorter side.
+// `roundness` is clamped to [0, 1]; 0 = sharp corners, 1 = fully rounded (stadium or circle).
+uniform_radii :: #force_inline proc(rect: Rectangle, roundness: f32) -> Rectangle_Radii {
+	cr := min(rect.width, rect.height) * clamp(roundness, 0, 1) * 0.5
+	return {cr, cr, cr, cr}
+}
+
+//----- Rectangle anchors (origin measured from rectangle's top-left) ----------------------------------
+
+center_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
+	return {rectangle.width * 0.5, rectangle.height * 0.5}
+}
+
+top_left_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
+	return {0, 0}
+}
+
+top_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
+	return {rectangle.width * 0.5, 0}
+}
+
+top_right_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
+	return {rectangle.width, 0}
+}
+
+left_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
+	return {0, rectangle.height * 0.5}
+}
+
+right_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
+	return {rectangle.width, rectangle.height * 0.5}
+}
+
+bottom_left_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
+	return {0, rectangle.height}
+}
+
+bottom_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
+	return {rectangle.width * 0.5, rectangle.height}
+}
+
+bottom_right_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
+	return {rectangle.width, rectangle.height}
+}
+
+//----- Triangle anchors (origin measured from AABB top-left) ----------------------------------
+
+center_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
+	bounds_min := Vec2{min(v1.x, v2.x, v3.x), min(v1.y, v2.y, v3.y)}
+	return (v1 + v2 + v3) / 3 - bounds_min
+}
+
+top_left_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
+	return {0, 0}
+}
+
+top_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
+	min_x := min(v1.x, v2.x, v3.x)
+	max_x := max(v1.x, v2.x, v3.x)
+	return {(max_x - min_x) * 0.5, 0}
+}
+
+top_right_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
+	min_x := min(v1.x, v2.x, v3.x)
+	max_x := max(v1.x, v2.x, v3.x)
+	return {max_x - min_x, 0}
+}
+
+left_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
+	min_y := min(v1.y, v2.y, v3.y)
+	max_y := max(v1.y, v2.y, v3.y)
+	return {0, (max_y - min_y) * 0.5}
+}
+
+right_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
+	bounds_min := Vec2{min(v1.x, v2.x, v3.x), min(v1.y, v2.y, v3.y)}
+	bounds_max := Vec2{max(v1.x, v2.x, v3.x), max(v1.y, v2.y, v3.y)}
+	return {bounds_max.x - bounds_min.x, (bounds_max.y - bounds_min.y) * 0.5}
+}
+
+bottom_left_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
+	min_y := min(v1.y, v2.y, v3.y)
+	max_y := max(v1.y, v2.y, v3.y)
+	return {0, max_y - min_y}
+}
+
+bottom_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
+	bounds_min := Vec2{min(v1.x, v2.x, v3.x), min(v1.y, v2.y, v3.y)}
+	bounds_max := Vec2{max(v1.x, v2.x, v3.x), max(v1.y, v2.y, v3.y)}
+	return {(bounds_max.x - bounds_min.x) * 0.5, bounds_max.y - bounds_min.y}
+}
+
+bottom_right_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
+	bounds_min := Vec2{min(v1.x, v2.x, v3.x), min(v1.y, v2.y, v3.y)}
+	bounds_max := Vec2{max(v1.x, v2.x, v3.x), max(v1.y, v2.y, v3.y)}
+	return bounds_max - bounds_min
+}
+
+//----- Procedure groups ----------------------------------
+
 center_of :: proc {
 	center_of_rectangle,
 	center_of_triangle,

draw/pipeline_2d_base.odin

@@ -1,827 +0,0 @@
-package draw
-
-import "core:c"
-import "core:log"
-import "core:mem"
-import sdl "vendor:sdl3"
-
-// Vertex layout for tessellated and text geometry.
-// IMPORTANT: `color` must be premultiplied alpha (RGB channels pre-scaled by alpha).
-// The tessellated fragment shader passes vertex color through directly — it does NOT
-// premultiply. The blend state is ONE, ONE_MINUS_SRC_ALPHA (premultiplied-over).
-// Use `premultiply_color` when constructing vertices manually for `prepare_shape`.
-Vertex :: struct {
-	position: Vec2,
-	uv:       [2]f32,
-	color:    Color,
-}
-
-TextBatch :: struct {
-	atlas_texture: ^sdl.GPUTexture,
-	vertex_start:  u32,
-	vertex_count:  u32,
-	index_start:   u32,
-	index_count:   u32,
-}
-
-// ----------------------------------------------------------------------------------------------------------------
-// ----- SDF primitive types -----------
-// ----------------------------------------------------------------------------------------------------------------
-
-// The SDF path evaluates one of four signed distance functions per primitive, dispatched
-// by Shape_Kind encoded in the low byte of Base_2D_Primitive.flags:
-//
-//   RRect    — rounded rectangle with per-corner radii (sdRoundedBox). Also covers circles
-//              (uniform radii = half-size), capsule-style line segments (rotated, max rounding),
-//              and other RRect-reducible shapes.
-//   NGon     — regular polygon with N sides and optional rounding.
-//   Ellipse  — approximate ellipse (non-exact SDF, suitable for UI but not for shape merging).
-//   Ring_Arc — annular ring with optional angular clipping. Covers full rings, partial arcs,
-//              pie slices (inner_radius = 0), and loading spinners.
-Shape_Kind :: enum u8 {
-	Solid    = 0, // tessellated path (mode marker; not a real SDF kind)
-	RRect    = 1,
-	NGon     = 2,
-	Ellipse  = 3,
-	Ring_Arc = 4,
-}
-
-Shape_Flag :: enum u8 {
-	Textured, // bit 0: sample texture using uv_rect (mutually exclusive with Gradient via Brush union)
-	Gradient, // bit 1: 2-color gradient using effects.gradient_color as end/outer color
-	Gradient_Radial, // bit 2: if set with Gradient, radial from center; else linear at angle
-	Outline, // bit 3: outer outline band using effects.outline_color; CPU expands bounds by outline_width
-	Rotated, // bit 4: shape has non-zero rotation; rotation_sc contains packed sin/cos
-	Arc_Narrow, // bit 5: ring arc span ≤ π — intersect half-planes. Neither Arc bit = full ring.
-	Arc_Wide, // bit 6: ring arc span > π — union half-planes. Neither Arc bit = full ring.
-}
-
-Shape_Flags :: bit_set[Shape_Flag;u8]
-
-RRect_Params :: struct {
-	half_size:    [2]f32,
-	radii:        [4]f32,
-	half_feather: f32, // feather_px * 0.5; shader uses smoothstep(-h, h, d)
-	_:            f32,
-}
-
-NGon_Params :: struct {
-	radius:       f32,
-	sides:        f32,
-	half_feather: f32, // feather_px * 0.5; shader uses smoothstep(-h, h, d)
-	_:            [5]f32,
-}
-
-Ellipse_Params :: struct {
-	radii:        [2]f32,
-	half_feather: f32, // feather_px * 0.5; shader uses smoothstep(-h, h, d)
-	_:            [5]f32,
-}
-
-Ring_Arc_Params :: struct {
-	inner_radius: f32, // inner radius in physical pixels (0 for pie slice)
-	outer_radius: f32, // outer radius in physical pixels
-	normal_start: [2]f32, // pre-computed outward normal of start edge: (sin(start), -cos(start))
-	normal_end:   [2]f32, // pre-computed outward normal of end edge: (-sin(end), cos(end))
-	half_feather: f32, // feather_px * 0.5; shader uses smoothstep(-h, h, d)
-	_:            f32,
-}
-
-Shape_Params :: struct #raw_union {
-	rrect:    RRect_Params,
-	ngon:     NGon_Params,
-	ellipse:  Ellipse_Params,
-	ring_arc: Ring_Arc_Params,
-	raw:      [8]f32,
-}
-#assert(size_of(Shape_Params) == 32)
-
-// GPU-side storage for 2-color gradient parameters and/or outline parameters.
-// Packed into 16 bytes. Independent from uv_rect — texture and outline can coexist.
-// The shader reads gradient_color and outline_color via unpackUnorm4x8.
-// gradient_dir_sc stores the pre-computed gradient direction as (cos, sin) in f16 pair
-// via unpackHalf2x16. outline_packed stores outline_width as f16 via unpackHalf2x16.
-Gradient_Outline :: struct {
-	gradient_color:  Color, //  0: end (linear) or outer (radial) gradient color
-	outline_color:   Color, //  4: outline band color
-	gradient_dir_sc: u32, //  8: packed f16 pair: low = cos(angle), high = sin(angle) — pre-computed gradient direction
-	outline_packed:  u32, // 12: packed f16 pair: low = outline_width (f16, physical pixels), high = reserved
-}
-#assert(size_of(Gradient_Outline) == 16)
-
-// GPU layout: 96 bytes, std430-compatible. The shader declares this as a storage buffer struct.
-// The low byte of `flags` encodes the Shape_Kind (0 = tessellated, 1-4 = SDF kinds).
-// Bits 8-15 encode Shape_Flags (Textured, Gradient, Gradient_Radial, Outline, Rotated, Arc_Narrow, Arc_Wide).
-// rotation_sc stores pre-computed sin/cos of the rotation angle as a packed f16 pair,
-// avoiding per-pixel trigonometry in the fragment shader. Only read when .Rotated is set.
-//
-// Named Base_2D_Primitive (not just Primitive) to disambiguate from Backdrop_Primitive in
-// backdrop.odin. The two pipelines have unrelated GPU layouts and unrelated fragment-shader
-// contracts; pairing each with its own primitive type keeps cross-references unambiguous
-// when grepping the codebase.
-Base_2D_Primitive :: struct {
-	bounds:      [4]f32, //  0: min_x, min_y, max_x, max_y (world-space, pre-DPI)
-	color:       Color, // 16: u8x4, fill color / gradient start color / texture tint
-	flags:       u32, // 20: low byte = Shape_Kind, bits 8+ = Shape_Flags
-	rotation_sc: u32, // 24: packed f16 pair: low = sin(angle), high = cos(angle). Requires .Rotated flag.
-	_pad:        f32, // 28: reserved for future use
-	params:      Shape_Params, // 32: per-kind shape parameters (raw union, 32 bytes)
-	uv_rect:     [4]f32, // 64: texture UV coordinates (u_min, v_min, u_max, v_max). Read when .Textured.
-	effects:     Gradient_Outline, // 80: gradient and/or outline parameters. Read when .Gradient and/or .Outline.
-}
-#assert(size_of(Base_2D_Primitive) == 96)
-
-// Pack shape kind and flags into the Base_2D_Primitive.flags field. The low byte encodes the
-// Shape_Kind (which also serves as the SDF mode marker — kind > 0 means SDF path). The
-// tessellated path leaves the field at 0 (Solid kind, set by vertex shader zero-initialization).
-pack_kind_flags :: #force_inline proc(kind: Shape_Kind, flags: Shape_Flags) -> u32 {
-	return u32(kind) | (u32(transmute(u8)flags) << 8)
-}
-
-// Pack two f16 values into a single u32 for GPU consumption via unpackHalf2x16.
-// Used to pack gradient_dir_sc (cos/sin) and outline_packed (width/reserved) in Gradient_Outline.
-pack_f16_pair :: #force_inline proc(low, high: f16) -> u32 {
-	return u32(transmute(u16)low) | (u32(transmute(u16)high) << 16)
-}
-
-Pipeline_2D_Base :: struct {
-	sdl_pipeline:     ^sdl.GPUGraphicsPipeline,
-	vertex_buffer:    Buffer,
-	index_buffer:     Buffer,
-	unit_quad_buffer: ^sdl.GPUBuffer,
-	primitive_buffer: Buffer,
-	white_texture:    ^sdl.GPUTexture,
-	sampler:          ^sdl.GPUSampler,
-}
-
-// MSAA is not supported by levlib (see init's doc comment in draw.odin); the PSO is hard-wired
-// to single-sample. SDF text and shapes provide analytical AA via smoothstep; tessellated user
-// geometry is not anti-aliased.
-@(private)
-create_pipeline_2d_base :: proc(
-	device: ^sdl.GPUDevice,
-	window: ^sdl.Window,
-) -> (
-	pipeline: Pipeline_2D_Base,
-	ok: bool,
-) {
-	// On failure, clean up any partially-created resources
-	defer if !ok {
-		if pipeline.sampler != nil do sdl.ReleaseGPUSampler(device, pipeline.sampler)
-		if pipeline.white_texture != nil do sdl.ReleaseGPUTexture(device, pipeline.white_texture)
-		if pipeline.unit_quad_buffer != nil do sdl.ReleaseGPUBuffer(device, pipeline.unit_quad_buffer)
-		if pipeline.primitive_buffer.gpu != nil do destroy_buffer(device, &pipeline.primitive_buffer)
-		if pipeline.index_buffer.gpu != nil do destroy_buffer(device, &pipeline.index_buffer)
-		if pipeline.vertex_buffer.gpu != nil do destroy_buffer(device, &pipeline.vertex_buffer)
-		if pipeline.sdl_pipeline != nil do sdl.ReleaseGPUGraphicsPipeline(device, pipeline.sdl_pipeline)
-	}
-
-	active_shader_formats := sdl.GetGPUShaderFormats(device)
-	if PLATFORM_SHADER_FORMAT_FLAG not_in active_shader_formats {
-		log.errorf(
-			"draw: no embedded shader matches active GPU formats; this build supports %v but device reports %v",
-			PLATFORM_SHADER_FORMAT,
-			active_shader_formats,
-		)
-		return pipeline, false
-	}
-
-	log.debug("Loaded", len(BASE_VERT_2D_RAW), "vert bytes")
-	log.debug("Loaded", len(BASE_FRAG_2D_RAW), "frag bytes")
-
-	vert_info := sdl.GPUShaderCreateInfo {
-		code_size           = len(BASE_VERT_2D_RAW),
-		code                = raw_data(BASE_VERT_2D_RAW),
-		entrypoint          = SHADER_ENTRY,
-		format              = {PLATFORM_SHADER_FORMAT_FLAG},
-		stage               = .VERTEX,
-		num_uniform_buffers = 1,
-		num_storage_buffers = 1,
-	}
-
-	frag_info := sdl.GPUShaderCreateInfo {
-		code_size    = len(BASE_FRAG_2D_RAW),
-		code         = raw_data(BASE_FRAG_2D_RAW),
-		entrypoint   = SHADER_ENTRY,
-		format       = {PLATFORM_SHADER_FORMAT_FLAG},
-		stage        = .FRAGMENT,
-		num_samplers = 1,
-	}
-
-	vert_shader := sdl.CreateGPUShader(device, vert_info)
-	if vert_shader == nil {
-		log.errorf("Could not create draw vertex shader: %s", sdl.GetError())
-		return pipeline, false
-	}
-
-	frag_shader := sdl.CreateGPUShader(device, frag_info)
-	if frag_shader == nil {
-		sdl.ReleaseGPUShader(device, vert_shader)
-		log.errorf("Could not create draw fragment shader: %s", sdl.GetError())
-		return pipeline, false
-	}
-
-	vertex_attributes: [3]sdl.GPUVertexAttribute = {
-		// position (GLSL location 0)
-		sdl.GPUVertexAttribute{buffer_slot = 0, location = 0, format = .FLOAT2, offset = 0},
-		// uv (GLSL location 1)
-		sdl.GPUVertexAttribute{buffer_slot = 0, location = 1, format = .FLOAT2, offset = size_of([2]f32)},
-		// color (GLSL location 2, u8x4 normalized to float by GPU)
-		sdl.GPUVertexAttribute{buffer_slot = 0, location = 2, format = .UBYTE4_NORM, offset = size_of([2]f32) * 2},
-	}
-
-	pipeline_info := sdl.GPUGraphicsPipelineCreateInfo {
-		vertex_shader = vert_shader,
-		fragment_shader = frag_shader,
-		primitive_type = .TRIANGLELIST,
-		multisample_state = sdl.GPUMultisampleState{sample_count = ._1},
-		target_info = sdl.GPUGraphicsPipelineTargetInfo {
-			color_target_descriptions = &sdl.GPUColorTargetDescription {
-				format = sdl.GetGPUSwapchainTextureFormat(device, window),
-				// Premultiplied-alpha blending: src outputs RGB pre-multiplied by alpha,
-				// so src factor is ONE (not SRC_ALPHA). This eliminates the per-pixel
-				// divide in the outline path and is the standard blend mode used by
-				// Skia, Flutter, and GPUI.
-				blend_state = sdl.GPUColorTargetBlendState {
-					enable_blend = true,
-					enable_color_write_mask = true,
-					src_color_blendfactor = .ONE,
-					dst_color_blendfactor = .ONE_MINUS_SRC_ALPHA,
-					color_blend_op = .ADD,
-					src_alpha_blendfactor = .ONE,
-					dst_alpha_blendfactor = .ONE_MINUS_SRC_ALPHA,
-					alpha_blend_op = .ADD,
-					color_write_mask = sdl.GPUColorComponentFlags{.R, .G, .B, .A},
-				},
-			},
-			num_color_targets         = 1,
-		},
-		vertex_input_state = sdl.GPUVertexInputState {
-			vertex_buffer_descriptions = &sdl.GPUVertexBufferDescription {
-				slot = 0,
-				input_rate = .VERTEX,
-				pitch = size_of(Vertex),
-			},
-			num_vertex_buffers = 1,
-			vertex_attributes = raw_data(vertex_attributes[:]),
-			num_vertex_attributes = 3,
-		},
-	}
-
-	pipeline.sdl_pipeline = sdl.CreateGPUGraphicsPipeline(device, pipeline_info)
-	// Shaders are no longer needed regardless of pipeline creation success
-	sdl.ReleaseGPUShader(device, vert_shader)
-	sdl.ReleaseGPUShader(device, frag_shader)
-	if pipeline.sdl_pipeline == nil {
-		log.errorf("Failed to create draw graphics pipeline: %s", sdl.GetError())
-		return pipeline, false
-	}
-
-	// Create vertex buffer
-	vert_buf_ok: bool
-	pipeline.vertex_buffer, vert_buf_ok = create_buffer(
-		device,
-		size_of(Vertex) * BUFFER_INIT_SIZE,
-		sdl.GPUBufferUsageFlags{.VERTEX},
-	)
-	if !vert_buf_ok do return pipeline, false
-
-	// Create index buffer (used by text)
-	idx_buf_ok: bool
-	pipeline.index_buffer, idx_buf_ok = create_buffer(
-		device,
-		size_of(c.int) * BUFFER_INIT_SIZE,
-		sdl.GPUBufferUsageFlags{.INDEX},
-	)
-	if !idx_buf_ok do return pipeline, false
-
-	// Create primitive storage buffer (used by SDF instanced drawing)
-	prim_buf_ok: bool
-	pipeline.primitive_buffer, prim_buf_ok = create_buffer(
-		device,
-		size_of(Base_2D_Primitive) * BUFFER_INIT_SIZE,
-		sdl.GPUBufferUsageFlags{.GRAPHICS_STORAGE_READ},
-	)
-	if !prim_buf_ok do return pipeline, false
-
-	// Create static 6-vertex unit quad buffer (two triangles, TRIANGLELIST)
-	pipeline.unit_quad_buffer = sdl.CreateGPUBuffer(
-		device,
-		sdl.GPUBufferCreateInfo{usage = {.VERTEX}, size = 6 * size_of(Vertex)},
-	)
-	if pipeline.unit_quad_buffer == nil {
-		log.errorf("Failed to create unit quad buffer: %s", sdl.GetError())
-		return pipeline, false
-	}
-
-	// Create 1x1 white pixel texture
-	pipeline.white_texture = sdl.CreateGPUTexture(
-		device,
-		sdl.GPUTextureCreateInfo {
-			type = .D2,
-			format = .R8G8B8A8_UNORM,
-			usage = {.SAMPLER},
-			width = 1,
-			height = 1,
-			layer_count_or_depth = 1,
-			num_levels = 1,
-			sample_count = ._1,
-		},
-	)
-	if pipeline.white_texture == nil {
-		log.errorf("Failed to create white pixel texture: %s", sdl.GetError())
-		return pipeline, false
-	}
-
-	// Upload white pixel and unit quad data in a single command buffer
-	white_pixel := Color{255, 255, 255, 255}
-	white_transfer_buf := sdl.CreateGPUTransferBuffer(
-		device,
-		sdl.GPUTransferBufferCreateInfo{usage = .UPLOAD, size = size_of(white_pixel)},
-	)
-	if white_transfer_buf == nil {
-		log.errorf("Failed to create white pixel transfer buffer: %s", sdl.GetError())
-		return pipeline, false
-	}
-	defer sdl.ReleaseGPUTransferBuffer(device, white_transfer_buf)
-
-	white_ptr := sdl.MapGPUTransferBuffer(device, white_transfer_buf, false)
-	if white_ptr == nil {
-		log.errorf("Failed to map white pixel transfer buffer: %s", sdl.GetError())
-		return pipeline, false
-	}
-	mem.copy(white_ptr, &white_pixel, size_of(white_pixel))
-	sdl.UnmapGPUTransferBuffer(device, white_transfer_buf)
-
-	quad_verts := [6]Vertex {
-		{position = {0, 0}},
-		{position = {1, 0}},
-		{position = {0, 1}},
-		{position = {0, 1}},
-		{position = {1, 0}},
-		{position = {1, 1}},
-	}
-	quad_transfer_buf := sdl.CreateGPUTransferBuffer(
-		device,
-		sdl.GPUTransferBufferCreateInfo{usage = .UPLOAD, size = size_of(quad_verts)},
-	)
-	if quad_transfer_buf == nil {
-		log.errorf("Failed to create unit quad transfer buffer: %s", sdl.GetError())
-		return pipeline, false
-	}
-	defer sdl.ReleaseGPUTransferBuffer(device, quad_transfer_buf)
-
-	quad_ptr := sdl.MapGPUTransferBuffer(device, quad_transfer_buf, false)
-	if quad_ptr == nil {
-		log.errorf("Failed to map unit quad transfer buffer: %s", sdl.GetError())
-		return pipeline, false
-	}
-	mem.copy(quad_ptr, &quad_verts, size_of(quad_verts))
-	sdl.UnmapGPUTransferBuffer(device, quad_transfer_buf)
-
-	upload_cmd_buffer := sdl.AcquireGPUCommandBuffer(device)
-	if upload_cmd_buffer == nil {
-		log.errorf("Failed to acquire command buffer for init upload: %s", sdl.GetError())
-		return pipeline, false
-	}
-	upload_pass := sdl.BeginGPUCopyPass(upload_cmd_buffer)
-
-	sdl.UploadToGPUTexture(
-		upload_pass,
-		sdl.GPUTextureTransferInfo{transfer_buffer = white_transfer_buf},
-		sdl.GPUTextureRegion{texture = pipeline.white_texture, w = 1, h = 1, d = 1},
-		false,
-	)
-
-	sdl.UploadToGPUBuffer(
-		upload_pass,
-		sdl.GPUTransferBufferLocation{transfer_buffer = quad_transfer_buf},
-		sdl.GPUBufferRegion{buffer = pipeline.unit_quad_buffer, offset = 0, size = size_of(quad_verts)},
-		false,
-	)
-
-	sdl.EndGPUCopyPass(upload_pass)
-	if !sdl.SubmitGPUCommandBuffer(upload_cmd_buffer) {
-		log.errorf("Failed to submit init upload command buffer: %s", sdl.GetError())
-		return pipeline, false
-	}
-
-	log.debug("White pixel texture and unit quad buffer created and uploaded")
-
-	// Create sampler (shared by shapes and text)
-	pipeline.sampler = sdl.CreateGPUSampler(
-		device,
-		sdl.GPUSamplerCreateInfo {
-			min_filter = .LINEAR,
-			mag_filter = .LINEAR,
-			mipmap_mode = .LINEAR,
-			address_mode_u = .CLAMP_TO_EDGE,
-			address_mode_v = .CLAMP_TO_EDGE,
-			address_mode_w = .CLAMP_TO_EDGE,
-		},
-	)
-	if pipeline.sampler == nil {
-		log.errorf("Could not create GPU sampler: %s", sdl.GetError())
-		return pipeline, false
-	}
-
-	log.debug("Done creating unified draw pipeline")
-	return pipeline, true
-}
-
-@(private)
-upload :: proc(device: ^sdl.GPUDevice, pass: ^sdl.GPUCopyPass) {
-	// Upload vertices (shapes then text into one buffer)
-	shape_vert_count := u32(len(GLOB.tmp_shape_verts))
-	text_vert_count := u32(len(GLOB.tmp_text_verts))
-	total_vert_count := shape_vert_count + text_vert_count
-
-	if total_vert_count > 0 {
-		total_vert_size := total_vert_count * size_of(Vertex)
-		shape_vert_size := shape_vert_count * size_of(Vertex)
-		text_vert_size := text_vert_count * size_of(Vertex)
-
-		grow_buffer_if_needed(
-			device,
-			&GLOB.pipeline_2d_base.vertex_buffer,
-			total_vert_size,
-			sdl.GPUBufferUsageFlags{.VERTEX},
-		)
-
-		vert_array := sdl.MapGPUTransferBuffer(device, GLOB.pipeline_2d_base.vertex_buffer.transfer, false)
-		if vert_array == nil {
-			log.panicf("Failed to map vertex transfer buffer: %s", sdl.GetError())
-		}
-		if shape_vert_size > 0 {
-			mem.copy(vert_array, raw_data(GLOB.tmp_shape_verts), int(shape_vert_size))
-		}
-		if text_vert_size > 0 {
-			mem.copy(
-				rawptr(uintptr(vert_array) + uintptr(shape_vert_size)),
-				raw_data(GLOB.tmp_text_verts),
-				int(text_vert_size),
-			)
-		}
-		sdl.UnmapGPUTransferBuffer(device, GLOB.pipeline_2d_base.vertex_buffer.transfer)
-
-		sdl.UploadToGPUBuffer(
-			pass,
-			sdl.GPUTransferBufferLocation{transfer_buffer = GLOB.pipeline_2d_base.vertex_buffer.transfer},
-			sdl.GPUBufferRegion{buffer = GLOB.pipeline_2d_base.vertex_buffer.gpu, offset = 0, size = total_vert_size},
-			false,
-		)
-	}
-
-	// Upload text indices
-	index_count := u32(len(GLOB.tmp_text_indices))
-	if index_count > 0 {
-		index_size := index_count * size_of(c.int)
-
-		grow_buffer_if_needed(
-			device,
-			&GLOB.pipeline_2d_base.index_buffer,
-			index_size,
-			sdl.GPUBufferUsageFlags{.INDEX},
-		)
-
-		idx_array := sdl.MapGPUTransferBuffer(device, GLOB.pipeline_2d_base.index_buffer.transfer, false)
-		if idx_array == nil {
-			log.panicf("Failed to map index transfer buffer: %s", sdl.GetError())
-		}
-		mem.copy(idx_array, raw_data(GLOB.tmp_text_indices), int(index_size))
-		sdl.UnmapGPUTransferBuffer(device, GLOB.pipeline_2d_base.index_buffer.transfer)
-
-		sdl.UploadToGPUBuffer(
-			pass,
-			sdl.GPUTransferBufferLocation{transfer_buffer = GLOB.pipeline_2d_base.index_buffer.transfer},
-			sdl.GPUBufferRegion{buffer = GLOB.pipeline_2d_base.index_buffer.gpu, offset = 0, size = index_size},
-			false,
-		)
-	}
-
-	// Upload SDF primitives
-	prim_count := u32(len(GLOB.tmp_primitives))
-	if prim_count > 0 {
-		prim_size := prim_count * size_of(Base_2D_Primitive)
-
-		grow_buffer_if_needed(
-			device,
-			&GLOB.pipeline_2d_base.primitive_buffer,
-			prim_size,
-			sdl.GPUBufferUsageFlags{.GRAPHICS_STORAGE_READ},
-		)
-
-		prim_array := sdl.MapGPUTransferBuffer(device, GLOB.pipeline_2d_base.primitive_buffer.transfer, false)
-		if prim_array == nil {
-			log.panicf("Failed to map primitive transfer buffer: %s", sdl.GetError())
-		}
-		mem.copy(prim_array, raw_data(GLOB.tmp_primitives), int(prim_size))
-		sdl.UnmapGPUTransferBuffer(device, GLOB.pipeline_2d_base.primitive_buffer.transfer)
-
-		sdl.UploadToGPUBuffer(
-			pass,
-			sdl.GPUTransferBufferLocation{transfer_buffer = GLOB.pipeline_2d_base.primitive_buffer.transfer},
-			sdl.GPUBufferRegion{buffer = GLOB.pipeline_2d_base.primitive_buffer.gpu, offset = 0, size = prim_size},
-			false,
-		)
-	}
-}
-
-@(private)
-draw_layer :: proc(
-	device: ^sdl.GPUDevice,
-	window: ^sdl.Window,
-	cmd_buffer: ^sdl.GPUCommandBuffer,
-	render_texture: ^sdl.GPUTexture,
-	swapchain_width: u32,
-	swapchain_height: u32,
-	clear_color: [4]f32,
-	layer: ^Layer,
-) {
-	if layer.sub_batch_len == 0 {
-		if !GLOB.cleared {
-			pass := sdl.BeginGPURenderPass(
-				cmd_buffer,
-				&sdl.GPUColorTargetInfo {
-					texture = render_texture,
-					clear_color = sdl.FColor{clear_color[0], clear_color[1], clear_color[2], clear_color[3]},
-					load_op = .CLEAR,
-					store_op = .STORE,
-				},
-				1,
-				nil,
-			)
-			sdl.EndGPURenderPass(pass)
-			GLOB.cleared = true
-		}
-		return
-	}
-
-	bracket_start_abs := find_first_backdrop_in_layer(layer)
-	layer_end_abs := int(layer.sub_batch_start + layer.sub_batch_len)
-
-	if bracket_start_abs < 0 {
-		// Fast path: no backdrop in this layer; render the whole sub-batch range in one pass.
-		render_layer_sub_batch_range(
-			cmd_buffer,
-			render_texture,
-			swapchain_width,
-			swapchain_height,
-			clear_color,
-			layer,
-			int(layer.sub_batch_start),
-			layer_end_abs,
-		)
-		return
-	}
-
-	// Bracketed layer: Pass A → backdrop bracket → Pass B.
-	// See README.md § "Backdrop pipeline" for the full ordering semantics.
-	render_layer_sub_batch_range(
-		cmd_buffer,
-		render_texture,
-		swapchain_width,
-		swapchain_height,
-		clear_color,
-		layer,
-		int(layer.sub_batch_start),
-		bracket_start_abs,
-	)
-
-	run_backdrop_bracket(cmd_buffer, layer, swapchain_width, swapchain_height)
-
-	// Pass B: render the [bracket_start_abs, layer_end_abs) range. .Backdrop sub-batches in
-	// this range are dispatched by the bracket above and ignored here (the .Backdrop case in
-	// the inner switch is a no-op). LOAD is implied because Pass A or the bracket's V-
-	// composite has already touched render_texture.
-	render_layer_sub_batch_range(
-		cmd_buffer,
-		render_texture,
-		swapchain_width,
-		swapchain_height,
-		clear_color,
-		layer,
-		bracket_start_abs,
-		layer_end_abs,
-	)
-}
-
-// Render a sub-range of a layer's sub-batches in a single render pass. Iterates the layer's
-// scissors and walks each scissor's sub-batches, dispatching by kind. The `range_start_abs`
-// and `range_end_abs` parameters are absolute indices into GLOB.tmp_sub_batches; only sub-
-// batches within `[range_start_abs, range_end_abs)` are drawn.
-//
-// .Backdrop sub-batches in the range are always silently skipped — they are dispatched by
-// run_backdrop_bracket, not here. The empty .Backdrop case in the inner switch enforces this.
-//
-// Render-pass setup mirrors the original draw_layer: clear-or-load based on GLOB.cleared,
-// pipeline + storage + index buffer bound up front, then per-batch state tracking. After this
-// proc returns, GLOB.cleared is guaranteed true.
-//
-// If the range is empty after filtering (no eligible sub-batches at all), this proc still
-// honors the no-clear-yet contract by issuing a clear-only pass when needed; otherwise it
-// returns without opening a render pass.
-@(private)
-render_layer_sub_batch_range :: proc(
-	cmd_buffer: ^sdl.GPUCommandBuffer,
-	render_texture: ^sdl.GPUTexture,
-	swapchain_width: u32,
-	swapchain_height: u32,
-	clear_color: [4]f32,
-	layer: ^Layer,
-	range_start_abs: int,
-	range_end_abs: int,
-) {
-	if range_start_abs >= range_end_abs {
-		// Empty range. If we still owe a clear, do a clear-only pass; otherwise nothing to do.
-		if !GLOB.cleared {
-			pass := sdl.BeginGPURenderPass(
-				cmd_buffer,
-				&sdl.GPUColorTargetInfo {
-					texture = render_texture,
-					clear_color = sdl.FColor{clear_color[0], clear_color[1], clear_color[2], clear_color[3]},
-					load_op = .CLEAR,
-					store_op = .STORE,
-				},
-				1,
-				nil,
-			)
-			sdl.EndGPURenderPass(pass)
-			GLOB.cleared = true
-		}
-		return
-	}
-
-	render_pass := sdl.BeginGPURenderPass(
-		cmd_buffer,
-		&sdl.GPUColorTargetInfo {
-			texture = render_texture,
-			clear_color = sdl.FColor{clear_color[0], clear_color[1], clear_color[2], clear_color[3]},
-			load_op = GLOB.cleared ? .LOAD : .CLEAR,
-			store_op = .STORE,
-		},
-		1,
-		nil,
-	)
-	GLOB.cleared = true
-
-	sdl.BindGPUGraphicsPipeline(render_pass, GLOB.pipeline_2d_base.sdl_pipeline)
-
-	// Bind storage buffer (read by vertex shader in SDF mode)
-	sdl.BindGPUVertexStorageBuffers(
-		render_pass,
-		0,
-		([^]^sdl.GPUBuffer)(&GLOB.pipeline_2d_base.primitive_buffer.gpu),
-		1,
-	)
-
-	// Always bind index buffer — harmless if no indexed draws are issued
-	sdl.BindGPUIndexBuffer(
-		render_pass,
-		sdl.GPUBufferBinding{buffer = GLOB.pipeline_2d_base.index_buffer.gpu, offset = 0},
-		._32BIT,
-	)
-
-	// Shorthand aliases for frequently-used pipeline resources
-	main_vert_buf := GLOB.pipeline_2d_base.vertex_buffer.gpu
-	unit_quad := GLOB.pipeline_2d_base.unit_quad_buffer
-	white_texture := GLOB.pipeline_2d_base.white_texture
-	sampler := GLOB.pipeline_2d_base.sampler
-	width := f32(swapchain_width)
-	height := f32(swapchain_height)
-
-	// Initial GPU state: tessellated mode, main vertex buffer, no atlas bound yet
-	push_globals(cmd_buffer, width, height, .Tessellated)
-	sdl.BindGPUVertexBuffers(render_pass, 0, &sdl.GPUBufferBinding{buffer = main_vert_buf, offset = 0}, 1)
-
-	current_mode: Draw_Mode = .Tessellated
-	current_vert_buf := main_vert_buf
-	current_atlas: ^sdl.GPUTexture
-	current_sampler := sampler
-
-	// Text vertices live after shape vertices in the GPU vertex buffer
-	text_vertex_gpu_base := u32(len(GLOB.tmp_shape_verts))
-
-	for &scissor in GLOB.scissors[layer.scissor_start:][:layer.scissor_len] {
-		// Intersect this scissor's sub-batch span with the requested range.
-		scissor_start := int(scissor.sub_batch_start)
-		scissor_end := scissor_start + int(scissor.sub_batch_len)
-		effective_start := max(scissor_start, range_start_abs)
-		effective_end := min(scissor_end, range_end_abs)
-		if effective_start >= effective_end do continue
-
-		sdl.SetGPUScissor(render_pass, scissor.bounds)
-
-		for abs_idx in effective_start ..< effective_end {
-			batch := &GLOB.tmp_sub_batches[abs_idx]
-			switch batch.kind {
-			case .Tessellated:
-				if current_mode != .Tessellated {
-					push_globals(cmd_buffer, width, height, .Tessellated)
-					current_mode = .Tessellated
-				}
-				if current_vert_buf != main_vert_buf {
-					sdl.BindGPUVertexBuffers(render_pass, 0, &sdl.GPUBufferBinding{buffer = main_vert_buf, offset = 0}, 1)
-					current_vert_buf = main_vert_buf
-				}
-				// Determine texture and sampler for this batch
-				batch_texture: ^sdl.GPUTexture = white_texture
-				batch_sampler: ^sdl.GPUSampler = sampler
-				if batch.texture_id != INVALID_TEXTURE {
-					if bound_texture := texture_gpu_handle(batch.texture_id); bound_texture != nil {
-						batch_texture = bound_texture
-					}
-					batch_sampler = get_sampler(batch.sampler)
-				}
-				if current_atlas != batch_texture || current_sampler != batch_sampler {
-					sdl.BindGPUFragmentSamplers(
-						render_pass,
-						0,
-						&sdl.GPUTextureSamplerBinding{texture = batch_texture, sampler = batch_sampler},
-						1,
-					)
-					current_atlas = batch_texture
-					current_sampler = batch_sampler
-				}
-				sdl.DrawGPUPrimitives(render_pass, batch.count, 1, batch.offset, 0)
-
-			case .Text:
-				if current_mode != .Tessellated {
-					push_globals(cmd_buffer, width, height, .Tessellated)
-					current_mode = .Tessellated
-				}
-				if current_vert_buf != main_vert_buf {
-					sdl.BindGPUVertexBuffers(render_pass, 0, &sdl.GPUBufferBinding{buffer = main_vert_buf, offset = 0}, 1)
-					current_vert_buf = main_vert_buf
-				}
-				text_batch := &GLOB.tmp_text_batches[batch.offset]
-				if current_atlas != text_batch.atlas_texture {
-					sdl.BindGPUFragmentSamplers(
-						render_pass,
-						0,
-						&sdl.GPUTextureSamplerBinding{texture = text_batch.atlas_texture, sampler = sampler},
-						1,
-					)
-					current_atlas = text_batch.atlas_texture
-				}
-				sdl.DrawGPUIndexedPrimitives(
-					render_pass,
-					text_batch.index_count,
-					1,
-					text_batch.index_start,
-					i32(text_vertex_gpu_base + text_batch.vertex_start),
-					0,
-				)
-
-			case .SDF:
-				if current_mode != .SDF {
-					push_globals(cmd_buffer, width, height, .SDF)
-					current_mode = .SDF
-				}
-				if current_vert_buf != unit_quad {
-					sdl.BindGPUVertexBuffers(render_pass, 0, &sdl.GPUBufferBinding{buffer = unit_quad, offset = 0}, 1)
-					current_vert_buf = unit_quad
-				}
-				// Determine texture and sampler for this batch
-				batch_texture: ^sdl.GPUTexture = white_texture
-				batch_sampler: ^sdl.GPUSampler = sampler
-				if batch.texture_id != INVALID_TEXTURE {
-					if bound_texture := texture_gpu_handle(batch.texture_id); bound_texture != nil {
-						batch_texture = bound_texture
-					}
-					batch_sampler = get_sampler(batch.sampler)
-				}
-				if current_atlas != batch_texture || current_sampler != batch_sampler {
-					sdl.BindGPUFragmentSamplers(
-						render_pass,
-						0,
-						&sdl.GPUTextureSamplerBinding{texture = batch_texture, sampler = batch_sampler},
-						1,
-					)
-					current_atlas = batch_texture
-					current_sampler = batch_sampler
-				}
-				sdl.DrawGPUPrimitives(render_pass, 6, batch.count, 0, batch.offset)
-
-			case .Backdrop:
-			// Always a no-op here. Backdrop sub-batches are dispatched by run_backdrop_bracket;
-			// when this proc encounters one (only possible in Pass B, since Pass A and the no-
-			// backdrop fast path both stop their range before any .Backdrop index), we skip it.
-			}
-		}
-	}
-
-	sdl.EndGPURenderPass(render_pass)
-}
-
-destroy_pipeline_2d_base :: proc(device: ^sdl.GPUDevice, pipeline: ^Pipeline_2D_Base) {
-	destroy_buffer(device, &pipeline.vertex_buffer)
-	destroy_buffer(device, &pipeline.index_buffer)
-	destroy_buffer(device, &pipeline.primitive_buffer)
-	if pipeline.unit_quad_buffer != nil {
-		sdl.ReleaseGPUBuffer(device, pipeline.unit_quad_buffer)
-	}
-	sdl.ReleaseGPUTexture(device, pipeline.white_texture)
-	sdl.ReleaseGPUSampler(device, pipeline.sampler)
-	sdl.ReleaseGPUGraphicsPipeline(device, pipeline.sdl_pipeline)
-}

draw/shaders/generated/backdrop_blur.vert.metal

@@ -52,7 +52,7 @@ struct Uniforms
     float2 _pad0;
 };
 
-struct Backdrop_Primitive
+struct Gaussian_Blur_Primitive
 {
     float4 bounds;
     float4 radii;
@@ -61,7 +61,7 @@ struct Backdrop_Primitive
     uint color;
 };
 
-struct Backdrop_Primitive_1
+struct Gaussian_Blur_Primitive_1
 {
     float4 bounds;
     float4 radii;
@@ -70,9 +70,9 @@ struct Backdrop_Primitive_1
     uint color;
 };
 
-struct Backdrop_Primitives
+struct Gaussian_Blur_Primitives
 {
-    Backdrop_Primitive_1 primitives[1];
+    Gaussian_Blur_Primitive_1 primitives[1];
 };
 
 constant spvUnsafeArray<float2, 6> _97 = spvUnsafeArray<float2, 6>({ float2(0.0), float2(1.0, 0.0), float2(0.0, 1.0), float2(0.0, 1.0), float2(1.0, 0.0), float2(1.0) });
@@ -87,7 +87,7 @@ struct main0_out
     float4 gl_Position [[position]];
 };
 
-vertex main0_out main0(constant Uniforms& _13 [[buffer(0)]], const device Backdrop_Primitives& _69 [[buffer(1)]], uint gl_VertexIndex [[vertex_id]], uint gl_InstanceIndex [[instance_id]])
+vertex main0_out main0(constant Uniforms& _13 [[buffer(0)]], const device Gaussian_Blur_Primitives& _69 [[buffer(1)]], uint gl_VertexIndex [[vertex_id]], uint gl_InstanceIndex [[instance_id]])
 {
     main0_out out = {};
     if (_13.mode == 0u)
@@ -102,7 +102,7 @@ vertex main0_out main0(constant Uniforms& _13 [[buffer(0)]], const device Backdr
     }
     else
     {
-        Backdrop_Primitive p;
+        Gaussian_Blur_Primitive p;
         p.bounds = _69.primitives[int(gl_InstanceIndex)].bounds;
         p.radii = _69.primitives[int(gl_InstanceIndex)].radii;
         p.half_size = _69.primitives[int(gl_InstanceIndex)].half_size;

draw/shaders/generated/base_2d.vert.metal

@@ -10,7 +10,7 @@ struct Uniforms
     uint mode;
 };
 
-struct Base_2D_Primitive
+struct Core_2D_Primitive
 {
     float4 bounds;
     uint color;
@@ -23,7 +23,7 @@ struct Base_2D_Primitive
     uint4 effects;
 };
 
-struct Base_2D_Primitive_1
+struct Core_2D_Primitive_1
 {
     float4 bounds;
     uint color;
@@ -36,9 +36,9 @@ struct Base_2D_Primitive_1
     uint4 effects;
 };
 
-struct Base_2D_Primitives
+struct Core_2D_Primitives
 {
-    Base_2D_Primitive_1 primitives[1];
+    Core_2D_Primitive_1 primitives[1];
 };
 
 struct main0_out
@@ -60,7 +60,7 @@ struct main0_in
     float4 v_color [[attribute(2)]];
 };
 
-vertex main0_out main0(main0_in in [[stage_in]], constant Uniforms& _12 [[buffer(0)]], const device Base_2D_Primitives& _75 [[buffer(1)]], uint gl_InstanceIndex [[instance_id]])
+vertex main0_out main0(main0_in in [[stage_in]], constant Uniforms& _12 [[buffer(0)]], const device Core_2D_Primitives& _75 [[buffer(1)]], uint gl_InstanceIndex [[instance_id]])
 {
     main0_out out = {};
     if (_12.mode == 0u)
@@ -76,7 +76,7 @@ vertex main0_out main0(main0_in in [[stage_in]], constant Uniforms& _12 [[buffer
     }
     else
     {
-        Base_2D_Primitive p;
+        Core_2D_Primitive p;
         p.bounds = _75.primitives[int(gl_InstanceIndex)].bounds;
         p.color = _75.primitives[int(gl_InstanceIndex)].color;
         p.flags = _75.primitives[int(gl_InstanceIndex)].flags;

draw/shaders/source/backdrop_blur.vert

@@ -3,7 +3,7 @@
 // Unified backdrop blur vertex shader.
 // Handles both the 1D separable blur passes (fullscreen triangle, mode 0; used for
 // BOTH the H-pass and V-pass) and the composite pass (instanced unit-quad over
-// Backdrop_Primitive storage buffer, mode 1) for the second PSO of the backdrop bracket.
+// Gaussian_Blur_Primitive storage buffer, mode 1) for the second PSO of the backdrop bracket.
 // The first PSO (downsample) uses backdrop_fullscreen.vert.
 //
 // No vertex buffer for either mode. Mode 0 uses gl_VertexIndex 0..2 for a single
@@ -33,7 +33,7 @@ layout(location = 4) flat out float f_half_feather;
 
 // --- Uniforms (set 1) ---
 // Backdrop pipeline's own uniform block — distinct from the main pipeline's
-// Vertex_Uniforms. `mode` selects between H-blur (0) and V-composite (1).
+// Vertex_Uniforms_2D. `mode` selects between H-blur (0) and V-composite (1).
 layout(set = 1, binding = 0) uniform Uniforms {
     mat4 projection;
     float dpi_scale;
@@ -41,18 +41,18 @@ layout(set = 1, binding = 0) uniform Uniforms {
     vec2 _pad0;
 };
 
-// --- Backdrop primitive storage buffer (set 0) ---
+// --- Gaussian blur primitive storage buffer (set 0) ---
 // 48 bytes, std430-natural layout (no implicit padding). vec4 members are
 // front-loaded so their 16-byte alignment is satisfied without holes; the
 // vec2 and scalar tail packs tight to land the struct at a clean 48-byte
 // stride (a multiple of 16, so the array stride needs no rounding either).
-// Field semantics match the CPU-side Backdrop_Primitive declared in
+// Field semantics match the CPU-side Gaussian_Blur_Primitive declared in
 // levlib/draw/backdrop.odin; keep both in sync.
 //
-// Backdrop primitives are tint-only: outline is intentionally absent. Specialized
+// Gaussian blur primitives are tint-only: outline is intentionally absent. Specialized
 // edge effects (e.g. liquid-glass-style refraction outlines) would be a dedicated
 // primitive type with its own pipeline rather than a flag bit here.
-struct Backdrop_Primitive {
+struct Gaussian_Blur_Primitive {
     vec4 bounds; //  0-15: min_xy, max_xy (world-space)
     vec4 radii; // 16-31: per-corner radii (physical px)
     vec2 half_size; // 32-39: RRect half extents (physical px)
@@ -60,8 +60,8 @@ struct Backdrop_Primitive {
     uint color; // 44-47: tint, packed RGBA u8x4
 };
 
-layout(std430, set = 0, binding = 0) readonly buffer Backdrop_Primitives {
+layout(std430, set = 0, binding = 0) readonly buffer Gaussian_Blur_Primitives {
-    Backdrop_Primitive primitives[];
+    Gaussian_Blur_Primitive primitives[];
 };
 
 void main() {
@@ -82,8 +82,8 @@ void main() {
         f_radii = vec4(0.0);
         f_half_feather = 0.0;
     } else {
-        // ---- Mode 1: V-composite instanced unit-quad over Backdrop_Primitive ----
+        // ---- Mode 1: V-composite instanced unit-quad over Gaussian_Blur_Primitive ----
-        Backdrop_Primitive p = primitives[gl_InstanceIndex];
+        Gaussian_Blur_Primitive p = primitives[gl_InstanceIndex];
 
         // Unit-quad corners for TRIANGLELIST (2 triangles, 6 vertices):
         //   index 0 -> (0,0)   index 3 -> (0,1)

draw/shaders/source/backdrop_downsample.frag

@@ -26,8 +26,8 @@
 // working-texture coords (work_region_phys / factor), clamped to the texture bounds.
 
 layout(set = 3, binding = 0) uniform Uniforms {
-    vec2 inv_source_size;     // 1.0 / source_texture pixel dimensions
+    vec2 inv_source_size; // 1.0 / source_texture pixel dimensions
-    uint downsample_factor;   // 1, 2, 4, 8, or 16
+    uint downsample_factor; // 1, 2, 4, 8, or 16
     uint _pad0;
 };
 
@@ -55,13 +55,13 @@ void main() {
         // bilinear level), giving a 4-tap = 16-source-pixel uniform sample of the block.
         float off = float(downsample_factor) * 0.25;
         vec2 uv_tl = (src_block_center + vec2(-off, -off)) * inv_source_size;
-        vec2 uv_tr = (src_block_center + vec2( off, -off)) * inv_source_size;
+        vec2 uv_tr = (src_block_center + vec2(off, -off)) * inv_source_size;
-        vec2 uv_bl = (src_block_center + vec2(-off,  off)) * inv_source_size;
+        vec2 uv_bl = (src_block_center + vec2(-off, off)) * inv_source_size;
-        vec2 uv_br = (src_block_center + vec2( off,  off)) * inv_source_size;
+        vec2 uv_br = (src_block_center + vec2(off, off)) * inv_source_size;
         vec4 c = texture(source_tex, uv_tl)
-               + texture(source_tex, uv_tr)
+                + texture(source_tex, uv_tr)
-               + texture(source_tex, uv_bl)
+                + texture(source_tex, uv_bl)
-               + texture(source_tex, uv_br);
+                + texture(source_tex, uv_br);
         out_color = c * 0.25;
     }
 }

draw/shaders/source/base_2d.vert

@@ -23,10 +23,10 @@ layout(set = 1, binding = 0) uniform Uniforms {
 };
 
 // ---------- SDF primitive storage buffer ----------
-// Mirrors the CPU-side Base_2D_Primitive in pipeline_2d_base.odin. Named with the
+// Mirrors the CPU-side Core_2D_Primitive in core_2d.odin. Named with the
-// pipeline prefix so a project-wide grep on the type name matches both the GLSL
+// subsystem prefix so a project-wide grep on the type name matches both the GLSL
 // declaration and the Odin declaration.
-struct Base_2D_Primitive {
+struct Core_2D_Primitive {
     vec4 bounds; // 0-15
     uint color; // 16-19
     uint flags; // 20-23
@@ -38,8 +38,8 @@ struct Base_2D_Primitive {
     uvec4 effects; // 80-95: gradient/outline parameters (read when .Gradient/.Outline)
 };
 
-layout(std430, set = 0, binding = 0) readonly buffer Base_2D_Primitives {
+layout(std430, set = 0, binding = 0) readonly buffer Core_2D_Primitives {
-    Base_2D_Primitive primitives[];
+    Core_2D_Primitive primitives[];
 };
 
 // ---------- Entry point ----------
@@ -57,7 +57,7 @@ void main() {
         gl_Position = projection * vec4(v_position * dpi_scale, 0.0, 1.0);
     } else {
         // ---- Mode 1: SDF instanced quads ----
-        Base_2D_Primitive p = primitives[gl_InstanceIndex];
+        Core_2D_Primitive p = primitives[gl_InstanceIndex];
 
         vec2 corner = v_position; // unit quad corners: (0,0)-(1,1)
         vec2 world_pos = mix(p.bounds.xy, p.bounds.zw, corner);

draw/shapes.odin

@@ -1,765 +0,0 @@
-package draw
-
-import "core:math"
-
-// ----- Internal helpers ----
-
-// Internal
-extrude_line :: proc(
-	start, end_pos: Vec2,
-	thickness: f32,
-	color: Color,
-	vertices: []Vertex,
-	offset: int,
-) -> int {
-	direction := end_pos - start
-	delta_x := direction[0]
-	delta_y := direction[1]
-	length := math.sqrt(delta_x * delta_x + delta_y * delta_y)
-	if length < 0.0001 do return 0
-
-	scale := thickness / (2 * length)
-	perpendicular := Vec2{-delta_y * scale, delta_x * scale}
-
-	p0 := start + perpendicular
-	p1 := start - perpendicular
-	p2 := end_pos - perpendicular
-	p3 := end_pos + perpendicular
-
-	vertices[offset + 0] = solid_vertex(p0, color)
-	vertices[offset + 1] = solid_vertex(p1, color)
-	vertices[offset + 2] = solid_vertex(p2, color)
-	vertices[offset + 3] = solid_vertex(p0, color)
-	vertices[offset + 4] = solid_vertex(p2, color)
-	vertices[offset + 5] = solid_vertex(p3, color)
-
-	return 6
-}
-
-// Create a vertex for solid-color shape drawing (no texture, UV defaults to zero).
-// Color is premultiplied: the tessellated fragment shader passes it through directly
-// and the blend state is ONE, ONE_MINUS_SRC_ALPHA.
-solid_vertex :: proc(position: Vec2, color: Color) -> Vertex {
-	return Vertex{position = position, color = premultiply_color(color)}
-}
-
-emit_rectangle :: proc(x, y, width, height: f32, color: Color, vertices: []Vertex, offset: int) {
-	vertices[offset + 0] = solid_vertex({x, y}, color)
-	vertices[offset + 1] = solid_vertex({x + width, y}, color)
-	vertices[offset + 2] = solid_vertex({x + width, y + height}, color)
-	vertices[offset + 3] = solid_vertex({x, y}, color)
-	vertices[offset + 4] = solid_vertex({x + width, y + height}, color)
-	vertices[offset + 5] = solid_vertex({x, y + height}, color)
-}
-
-// Internal — submit an SDF primitive with optional texture binding.
-// The texture-aware counterpart of `draw.prepare_sdf_primitive`; lets shape procs route a
-// texture_id and sampler into the sub-batch without growing the public API.
-@(private)
-prepare_sdf_primitive_ex :: proc(
-	layer: ^Layer,
-	prim: Base_2D_Primitive,
-	texture_id: Texture_Id = INVALID_TEXTURE,
-	sampler: Sampler_Preset = DFT_SAMPLER,
-) {
-	offset := u32(len(GLOB.tmp_primitives))
-	append(&GLOB.tmp_primitives, prim)
-	scissor := &GLOB.scissors[layer.scissor_start + layer.scissor_len - 1]
-	append_or_extend_sub_batch(scissor, layer, .SDF, offset, 1, texture_id, sampler)
-}
-
-// Internal — resolve Texture_Fill zero-initialized fields to their defaults.
-// Odin structs zero-initialize; Color{} and Rectangle{} are all-zero which is not a
-// useful tint or UV rect. This proc substitutes sensible defaults for zero values.
-@(private)
-resolve_texture_defaults :: #force_inline proc(
-	tf: Texture_Fill,
-) -> (
-	tint: Color,
-	uv: Rectangle,
-	sampler: Sampler_Preset,
-) {
-	tint = tf.tint == Color{} ? DFT_TINT : tf.tint
-	uv = tf.uv_rect == Rectangle{} ? DFT_UV_RECT : tf.uv_rect
-	sampler = tf.sampler
-	return
-}
-
-//Internal
-//
-// Compute the visual center of a center-parametrized shape after applying
-// Convention B origin semantics: `center` is where the origin-point lands in
-// world space; the visual center is offset by -origin and then rotated around
-// the landing point.
-//   visual_center = center + R(θ) · (-origin)
-// When θ=0: visual_center = center - origin (pure positioning shift).
-// When origin={0,0}: visual_center = center (no change).
-compute_pivot_center :: proc(center: Vec2, origin: Vec2, sin_angle, cos_angle: f32) -> Vec2 {
-	if origin == {0, 0} do return center
-	return(
-		center +
-		{cos_angle * (-origin.x) - sin_angle * (-origin.y), sin_angle * (-origin.x) + cos_angle * (-origin.y)} \
-	)
-}
-
-// Compute the AABB half-extents of a rectangle with half-size (half_width, half_height) rotated by the given cos/sin.
-rotated_aabb_half_extents :: proc(half_width, half_height, cos_angle, sin_angle: f32) -> [2]f32 {
-	cos_abs := abs(cos_angle)
-	sin_abs := abs(sin_angle)
-	return {half_width * cos_abs + half_height * sin_abs, half_width * sin_abs + half_height * cos_abs}
-}
-
-// Pack sin/cos into the Base_2D_Primitive.rotation_sc field as two f16 values.
-pack_rotation_sc :: #force_inline proc(sin_angle, cos_angle: f32) -> u32 {
-	return pack_f16_pair(f16(sin_angle), f16(cos_angle))
-}
-
-
-// Internal
-//
-// Build an RRect Base_2D_Primitive with bounds, params, and rotation computed from rectangle geometry.
-// The caller sets color, flags, and uv fields on the returned primitive before submitting.
-build_rrect_primitive :: proc(
-	rect: Rectangle,
-	radii: Rectangle_Radii,
-	origin: Vec2,
-	rotation: f32,
-	feather_px: f32,
-) -> Base_2D_Primitive {
-	max_radius := min(rect.width, rect.height) * 0.5
-	clamped_top_left := clamp(radii.top_left, 0, max_radius)
-	clamped_top_right := clamp(radii.top_right, 0, max_radius)
-	clamped_bottom_right := clamp(radii.bottom_right, 0, max_radius)
-	clamped_bottom_left := clamp(radii.bottom_left, 0, max_radius)
-
-	half_feather := feather_px * 0.5
-	padding := half_feather / GLOB.dpi_scaling
-	dpi_scale := GLOB.dpi_scaling
-
-	half_width := rect.width * 0.5
-	half_height := rect.height * 0.5
-	center_x := rect.x + half_width - origin.x
-	center_y := rect.y + half_height - origin.y
-	sin_angle: f32 = 0
-	cos_angle: f32 = 1
-	has_rotation := false
-
-	if needs_transform(origin, rotation) {
-		rotation_radians := math.to_radians(rotation)
-		sin_angle, cos_angle = math.sincos(rotation_radians)
-		has_rotation = rotation != 0
-		transform := build_pivot_rotation_sc({rect.x + origin.x, rect.y + origin.y}, origin, cos_angle, sin_angle)
-		new_center := apply_transform(transform, {half_width, half_height})
-		center_x = new_center.x
-		center_y = new_center.y
-	}
-
-	bounds_half_width, bounds_half_height := half_width, half_height
-	if has_rotation {
-		expanded := rotated_aabb_half_extents(half_width, half_height, cos_angle, sin_angle)
-		bounds_half_width = expanded.x
-		bounds_half_height = expanded.y
-	}
-
-	prim := Base_2D_Primitive {
-		bounds      = {
-			center_x - bounds_half_width - padding,
-			center_y - bounds_half_height - padding,
-			center_x + bounds_half_width + padding,
-			center_y + bounds_half_height + padding,
-		},
-		rotation_sc = has_rotation ? pack_rotation_sc(sin_angle, cos_angle) : 0,
-	}
-	prim.params.rrect = RRect_Params {
-		half_size    = {half_width * dpi_scale, half_height * dpi_scale},
-		radii        = {
-			clamped_bottom_right * dpi_scale,
-			clamped_top_right * dpi_scale,
-			clamped_bottom_left * dpi_scale,
-			clamped_top_left * dpi_scale,
-		},
-		half_feather = half_feather,
-	}
-	return prim
-}
-
-// Internal
-//
-// Build an RRect Base_2D_Primitive for a circle (fully-rounded square RRect).
-// The caller sets color, flags, and uv fields on the returned primitive before submitting.
-build_circle_primitive :: proc(
-	center: Vec2,
-	radius: f32,
-	origin: Vec2,
-	rotation: f32,
-	feather_px: f32,
-) -> Base_2D_Primitive {
-	half_feather := feather_px * 0.5
-	padding := half_feather / GLOB.dpi_scaling
-	dpi_scale := GLOB.dpi_scaling
-
-	actual_center := center
-	if origin != {0, 0} {
-		sin_a, cos_a := math.sincos(math.to_radians(rotation))
-		actual_center = compute_pivot_center(center, origin, sin_a, cos_a)
-	}
-
-	prim := Base_2D_Primitive {
-		bounds = {
-			actual_center.x - radius - padding,
-			actual_center.y - radius - padding,
-			actual_center.x + radius + padding,
-			actual_center.y + radius + padding,
-		},
-	}
-	scaled_radius := radius * dpi_scale
-	prim.params.rrect = RRect_Params {
-		half_size    = {scaled_radius, scaled_radius},
-		radii        = {scaled_radius, scaled_radius, scaled_radius, scaled_radius},
-		half_feather = half_feather,
-	}
-	return prim
-}
-
-// Internal
-//
-// Build an Ellipse Base_2D_Primitive with bounds, params, and rotation computed from ellipse geometry.
-// The caller sets color, flags, and uv fields on the returned primitive before submitting.
-build_ellipse_primitive :: proc(
-	center: Vec2,
-	radius_horizontal, radius_vertical: f32,
-	origin: Vec2,
-	rotation: f32,
-	feather_px: f32,
-) -> Base_2D_Primitive {
-	half_feather := feather_px * 0.5
-	padding := half_feather / GLOB.dpi_scaling
-	dpi_scale := GLOB.dpi_scaling
-
-	actual_center := center
-	sin_angle: f32 = 0
-	cos_angle: f32 = 1
-	has_rotation := false
-
-	if needs_transform(origin, rotation) {
-		rotation_radians := math.to_radians(rotation)
-		sin_angle, cos_angle = math.sincos(rotation_radians)
-		actual_center = compute_pivot_center(center, origin, sin_angle, cos_angle)
-		has_rotation = rotation != 0
-	}
-
-	bound_horizontal, bound_vertical := radius_horizontal, radius_vertical
-	if has_rotation {
-		expanded := rotated_aabb_half_extents(radius_horizontal, radius_vertical, cos_angle, sin_angle)
-		bound_horizontal = expanded.x
-		bound_vertical = expanded.y
-	}
-
-	prim := Base_2D_Primitive {
-		bounds      = {
-			actual_center.x - bound_horizontal - padding,
-			actual_center.y - bound_vertical - padding,
-			actual_center.x + bound_horizontal + padding,
-			actual_center.y + bound_vertical + padding,
-		},
-		rotation_sc = has_rotation ? pack_rotation_sc(sin_angle, cos_angle) : 0,
-	}
-	prim.params.ellipse = Ellipse_Params {
-		radii        = {radius_horizontal * dpi_scale, radius_vertical * dpi_scale},
-		half_feather = half_feather,
-	}
-	return prim
-}
-
-// Internal
-//
-// Build an NGon Base_2D_Primitive with bounds, params, and rotation computed from polygon geometry.
-// The caller sets color, flags, and uv fields on the returned primitive before submitting.
-build_polygon_primitive :: proc(
-	center: Vec2,
-	sides: int,
-	radius: f32,
-	origin: Vec2,
-	rotation: f32,
-	feather_px: f32,
-) -> Base_2D_Primitive {
-	half_feather := feather_px * 0.5
-	padding := half_feather / GLOB.dpi_scaling
-	dpi_scale := GLOB.dpi_scaling
-
-	actual_center := center
-	if origin != {0, 0} && rotation != 0 {
-		sin_a, cos_a := math.sincos(math.to_radians(rotation))
-		actual_center = compute_pivot_center(center, origin, sin_a, cos_a)
-	}
-
-	rotation_radians := math.to_radians(rotation)
-	sin_rot, cos_rot := math.sincos(rotation_radians)
-
-	prim := Base_2D_Primitive {
-		bounds      = {
-			actual_center.x - radius - padding,
-			actual_center.y - radius - padding,
-			actual_center.x + radius + padding,
-			actual_center.y + radius + padding,
-		},
-		rotation_sc = rotation != 0 ? pack_rotation_sc(sin_rot, cos_rot) : 0,
-	}
-	prim.params.ngon = NGon_Params {
-		radius       = radius * math.cos(math.PI / f32(sides)) * dpi_scale,
-		sides        = f32(sides),
-		half_feather = half_feather,
-	}
-	return prim
-}
-
-// Internal
-//
-// Build a Ring_Arc Base_2D_Primitive with bounds and params computed from ring/arc geometry.
-// Pre-computes the angular boundary normals on the CPU so the fragment shader needs
-// no per-pixel sin/cos. The radial SDF uses max(inner-r, r-outer) which correctly
-// handles pie slices (inner_radius = 0) and full rings.
-// The caller sets color, flags, and uv fields on the returned primitive before submitting.
-build_ring_arc_primitive :: proc(
-	center: Vec2,
-	inner_radius, outer_radius: f32,
-	start_angle: f32,
-	end_angle: f32,
-	origin: Vec2,
-	rotation: f32,
-	feather_px: f32,
-) -> (
-	Base_2D_Primitive,
-	Shape_Flags,
-) {
-	half_feather := feather_px * 0.5
-	padding := half_feather / GLOB.dpi_scaling
-	dpi_scale := GLOB.dpi_scaling
-
-	actual_center := center
-	rotation_offset: f32 = 0
-	if needs_transform(origin, rotation) {
-		sin_a, cos_a := math.sincos(math.to_radians(rotation))
-		actual_center = compute_pivot_center(center, origin, sin_a, cos_a)
-		rotation_offset = math.to_radians(rotation)
-	}
-
-	start_rad := math.to_radians(start_angle) + rotation_offset
-	end_rad := math.to_radians(end_angle) + rotation_offset
-
-	// Normalize arc span to [0, 2π]
-	arc_span := end_rad - start_rad
-	if arc_span < 0 {
-		arc_span += 2 * math.PI
-	}
-
-	// Pre-compute edge normals and arc flags on CPU — no per-pixel trig needed.
-	// arc_flags: {} = full ring, {.Arc_Narrow} = span ≤ π (intersect), {.Arc_Wide} = span > π (union)
-	arc_flags: Shape_Flags = {}
-	normal_start: [2]f32 = {}
-	normal_end: [2]f32 = {}
-
-	if arc_span < 2 * math.PI - 0.001 {
-		sin_start, cos_start := math.sincos(start_rad)
-		sin_end, cos_end := math.sincos(end_rad)
-		normal_start = {sin_start, -cos_start}
-		normal_end = {-sin_end, cos_end}
-		arc_flags = arc_span <= math.PI ? {.Arc_Narrow} : {.Arc_Wide}
-	}
-
-	prim := Base_2D_Primitive {
-		bounds = {
-			actual_center.x - outer_radius - padding,
-			actual_center.y - outer_radius - padding,
-			actual_center.x + outer_radius + padding,
-			actual_center.y + outer_radius + padding,
-		},
-	}
-	prim.params.ring_arc = Ring_Arc_Params {
-		inner_radius = inner_radius * dpi_scale,
-		outer_radius = outer_radius * dpi_scale,
-		normal_start = normal_start,
-		normal_end   = normal_end,
-		half_feather = half_feather,
-	}
-	return prim, arc_flags
-}
-
-// Apply brush fill and outline to a primitive, then submit it.
-// Dispatches to the correct sub-batch based on the Brush variant.
-// All parameters (outline_width) are in logical pixels, matching the rest of the public API.
-// The helper converts to physical pixels for GPU packing internally.
-@(private)
-apply_brush_and_outline :: proc(
-	layer: ^Layer,
-	prim: ^Base_2D_Primitive,
-	kind: Shape_Kind,
-	brush: Brush,
-	outline_color: Color,
-	outline_width: f32,
-	extra_flags: Shape_Flags = {},
-) {
-	flags: Shape_Flags = extra_flags
-
-	// Fill — determined by the Brush variant.
-	texture_id := INVALID_TEXTURE
-	sampler := DFT_SAMPLER
-
-	switch b in brush {
-	case Color: prim.color = b
-	case Linear_Gradient:
-		flags += {.Gradient}
-		prim.color = b.start_color
-		prim.effects.gradient_color = b.end_color
-		rad := math.to_radians(b.angle)
-		sin_a, cos_a := math.sincos(rad)
-		prim.effects.gradient_dir_sc = pack_f16_pair(f16(cos_a), f16(sin_a))
-	case Radial_Gradient:
-		flags += {.Gradient, .Gradient_Radial}
-		prim.color = b.inner_color
-		prim.effects.gradient_color = b.outer_color
-	case Texture_Fill:
-		flags += {.Textured}
-		tint, uv, sam := resolve_texture_defaults(b)
-		prim.color = tint
-		prim.uv_rect = {uv.x, uv.y, uv.width, uv.height}
-		texture_id = b.id
-		sampler = sam
-	}
-
-	// Outline — orthogonal to all Brush variants.
-	if outline_width > 0 {
-		flags += {.Outline}
-		prim.effects.outline_color = outline_color
-		prim.effects.outline_packed = pack_f16_pair(f16(outline_width * GLOB.dpi_scaling), 0)
-		// Expand bounds to contain the outline (bounds are in logical pixels)
-		prim.bounds[0] -= outline_width
-		prim.bounds[1] -= outline_width
-		prim.bounds[2] += outline_width
-		prim.bounds[3] += outline_width
-	}
-
-	// Set .Rotated flag if rotation_sc was populated by the build proc
-	if prim.rotation_sc != 0 {
-		flags += {.Rotated}
-	}
-
-	prim.flags = pack_kind_flags(kind, flags)
-	prepare_sdf_primitive_ex(layer, prim^, texture_id, sampler)
-}
-
-// ---------------------------------------------------------------------------------------------------------------------
-// ----- SDF Rectangle procs -----------
-// ---------------------------------------------------------------------------------------------------------------------
-
-// Draw a filled rectangle via SDF with optional per-corner rounding radii.
-// Use `uniform_radii(rect, roundness)` to compute uniform radii from a 0–1 fraction.
-//
-// Origin semantics:
-//   `origin` is a local offset from the rect's top-left corner that selects both the positioning
-//   anchor and the rotation pivot. `rect.x, rect.y` specifies where that anchor point lands in
-//   world space. When `origin = {0, 0}` (default), `rect.x, rect.y` is the top-left corner.
-//   Rotation always occurs around the anchor point.
-rectangle :: proc(
-	layer: ^Layer,
-	rect: Rectangle,
-	brush: Brush,
-	outline_color: Color = {},
-	outline_width: f32 = 0,
-	radii: Rectangle_Radii = {},
-	origin: Vec2 = {},
-	rotation: f32 = 0,
-	feather_px: f32 = DFT_FEATHER_PX,
-) {
-	prim := build_rrect_primitive(rect, radii, origin, rotation, feather_px)
-	apply_brush_and_outline(layer, &prim, .RRect, brush, outline_color, outline_width)
-}
-
-// ---------------------------------------------------------------------------------------------------------------------
-// ----- SDF Circle procs (emit RRect primitives) ------
-// ---------------------------------------------------------------------------------------------------------------------
-
-// Draw a filled circle via SDF (emitted as a fully-rounded RRect).
-//
-// Origin semantics (Convention B):
-//   `origin` is a local offset from the shape's center that selects both the positioning anchor
-//   and the rotation pivot. The `center` parameter specifies where that anchor point lands in
-//   world space. When `origin = {0, 0}` (default), `center` is the visual center.
-//   When `origin = {r, 0}`, the point `r` pixels to the right of the shape center lands at
-//   `center`, shifting the shape left by `r`.
-circle :: proc(
-	layer: ^Layer,
-	center: Vec2,
-	radius: f32,
-	brush: Brush,
-	outline_color: Color = {},
-	outline_width: f32 = 0,
-	origin: Vec2 = {},
-	rotation: f32 = 0,
-	feather_px: f32 = DFT_FEATHER_PX,
-) {
-	prim := build_circle_primitive(center, radius, origin, rotation, feather_px)
-	apply_brush_and_outline(layer, &prim, .RRect, brush, outline_color, outline_width)
-}
-
-// ---------------------------------------------------------------------------------------------------------------------
-// ----- SDF Ellipse procs (emit Ellipse primitives) ---
-// ---------------------------------------------------------------------------------------------------------------------
-
-// Draw a filled ellipse via SDF.
-// Origin semantics: see `circle`.
-ellipse :: proc(
-	layer: ^Layer,
-	center: Vec2,
-	radius_horizontal, radius_vertical: f32,
-	brush: Brush,
-	outline_color: Color = {},
-	outline_width: f32 = 0,
-	origin: Vec2 = {},
-	rotation: f32 = 0,
-	feather_px: f32 = DFT_FEATHER_PX,
-) {
-	prim := build_ellipse_primitive(center, radius_horizontal, radius_vertical, origin, rotation, feather_px)
-	apply_brush_and_outline(layer, &prim, .Ellipse, brush, outline_color, outline_width)
-}
-
-// ---------------------------------------------------------------------------------------------------------------------
-// ----- SDF Polygon procs (emit NGon primitives) ------
-// ---------------------------------------------------------------------------------------------------------------------
-
-// Draw a filled regular polygon via SDF.
-// `sides` must be >= 3. The polygon is inscribed in a circle of the given `radius`.
-// Origin semantics: see `circle`.
-polygon :: proc(
-	layer: ^Layer,
-	center: Vec2,
-	sides: int,
-	radius: f32,
-	brush: Brush,
-	outline_color: Color = {},
-	outline_width: f32 = 0,
-	origin: Vec2 = {},
-	rotation: f32 = 0,
-	feather_px: f32 = DFT_FEATHER_PX,
-) {
-	if sides < 3 do return
-
-	prim := build_polygon_primitive(center, sides, radius, origin, rotation, feather_px)
-	apply_brush_and_outline(layer, &prim, .NGon, brush, outline_color, outline_width)
-}
-
-// ---------------------------------------------------------------------------------------------------------------------
-// ----- SDF Ring / Arc procs (emit Ring_Arc primitives) ----
-// ---------------------------------------------------------------------------------------------------------------------
-
-// Draw a ring, arc, or pie slice via SDF.
-// Full ring by default. Pass start_angle/end_angle (degrees) for partial arcs.
-// Use inner_radius = 0 for pie slices (sectors).
-// Origin semantics: see `circle`.
-ring :: proc(
-	layer: ^Layer,
-	center: Vec2,
-	inner_radius, outer_radius: f32,
-	brush: Brush,
-	outline_color: Color = {},
-	outline_width: f32 = 0,
-	start_angle: f32 = 0,
-	end_angle: f32 = DFT_CIRC_END_ANGLE,
-	origin: Vec2 = {},
-	rotation: f32 = 0,
-	feather_px: f32 = DFT_FEATHER_PX,
-) {
-	prim, arc_flags := build_ring_arc_primitive(
-		center,
-		inner_radius,
-		outer_radius,
-		start_angle,
-		end_angle,
-		origin,
-		rotation,
-		feather_px,
-	)
-	apply_brush_and_outline(layer, &prim, .Ring_Arc, brush, outline_color, outline_width, arc_flags)
-}
-
-// ---------------------------------------------------------------------------------------------------------------------
-// ----- SDF Line procs (emit rotated RRect primitives) ----
-// ---------------------------------------------------------------------------------------------------------------------
-
-// Draw a line segment via SDF (emitted as a rotated capsule-shaped RRect).
-// Round caps are produced by setting corner radii equal to half the thickness.
-line :: proc(
-	layer: ^Layer,
-	start_position, end_position: Vec2,
-	brush: Brush,
-	thickness: f32 = DFT_STROKE_THICKNESS,
-	outline_color: Color = {},
-	outline_width: f32 = 0,
-	feather_px: f32 = DFT_FEATHER_PX,
-) {
-	delta_x := end_position.x - start_position.x
-	delta_y := end_position.y - start_position.y
-	seg_length := math.sqrt(delta_x * delta_x + delta_y * delta_y)
-	if seg_length < 0.0001 do return
-	rotation_radians := math.atan2(delta_y, delta_x)
-	sin_angle, cos_angle := math.sincos(rotation_radians)
-
-	center_x := (start_position.x + end_position.x) * 0.5
-	center_y := (start_position.y + end_position.y) * 0.5
-
-	half_length := seg_length * 0.5
-	half_thickness := thickness * 0.5
-	cap_radius := half_thickness
-
-	half_feather := feather_px * 0.5
-	padding := half_feather / GLOB.dpi_scaling
-	dpi_scale := GLOB.dpi_scaling
-
-	// Expand bounds for rotation
-	bounds_half := rotated_aabb_half_extents(half_length + cap_radius, half_thickness, cos_angle, sin_angle)
-
-	prim := Base_2D_Primitive {
-		bounds      = {
-			center_x - bounds_half.x - padding,
-			center_y - bounds_half.y - padding,
-			center_x + bounds_half.x + padding,
-			center_y + bounds_half.y + padding,
-		},
-		rotation_sc = pack_rotation_sc(sin_angle, cos_angle),
-	}
-	prim.params.rrect = RRect_Params {
-		half_size    = {(half_length + cap_radius) * dpi_scale, half_thickness * dpi_scale},
-		radii        = {
-			cap_radius * dpi_scale,
-			cap_radius * dpi_scale,
-			cap_radius * dpi_scale,
-			cap_radius * dpi_scale,
-		},
-		half_feather = half_feather,
-	}
-	apply_brush_and_outline(layer, &prim, .RRect, brush, outline_color, outline_width)
-}
-
-// Draw a line strip via decomposed SDF line segments.
-line_strip :: proc(
-	layer: ^Layer,
-	points: []Vec2,
-	brush: Brush,
-	thickness: f32 = DFT_STROKE_THICKNESS,
-	outline_color: Color = {},
-	outline_width: f32 = 0,
-	feather_px: f32 = DFT_FEATHER_PX,
-) {
-	if len(points) < 2 do return
-	for i in 0 ..< len(points) - 1 {
-		line(layer, points[i], points[i + 1], brush, thickness, outline_color, outline_width, feather_px)
-	}
-}
-
-
-// ---------------------------------------------------------------------------------------------------------------------
-// ----- Helpers ----------------
-// ---------------------------------------------------------------------------------------------------------------------
-
-// Returns uniform radii (all corners the same) as a fraction of the shorter side.
-// `roundness` is clamped to [0, 1]; 0 = sharp corners, 1 = fully rounded (stadium or circle).
-uniform_radii :: #force_inline proc(rect: Rectangle, roundness: f32) -> Rectangle_Radii {
-	cr := min(rect.width, rect.height) * clamp(roundness, 0, 1) * 0.5
-	return {cr, cr, cr, cr}
-}
-
-// Return Vec2 pixel offsets for use as the `origin` parameter of draw calls.
-// Composable with normal vector +/- arithmetic.
-//
-// Text anchor helpers are in text.odin (they depend on measure_text / SDL_ttf).
-
-// ----- Rectangle anchors (origin measured from rectangle's top-left) ---------------------------------------------
-
-center_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
-	return {rectangle.width * 0.5, rectangle.height * 0.5}
-}
-
-top_left_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
-	return {0, 0}
-}
-
-top_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
-	return {rectangle.width * 0.5, 0}
-}
-
-top_right_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
-	return {rectangle.width, 0}
-}
-
-left_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
-	return {0, rectangle.height * 0.5}
-}
-
-right_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
-	return {rectangle.width, rectangle.height * 0.5}
-}
-
-bottom_left_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
-	return {0, rectangle.height}
-}
-
-bottom_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
-	return {rectangle.width * 0.5, rectangle.height}
-}
-
-bottom_right_of_rectangle :: #force_inline proc(rectangle: Rectangle) -> Vec2 {
-	return {rectangle.width, rectangle.height}
-}
-
-// ----- Triangle anchors (origin measured from AABB top-left) -----------------------------------------------------
-
-center_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
-	bounds_min := Vec2{min(v1.x, v2.x, v3.x), min(v1.y, v2.y, v3.y)}
-	return (v1 + v2 + v3) / 3 - bounds_min
-}
-
-top_left_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
-	return {0, 0}
-}
-
-top_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
-	min_x := min(v1.x, v2.x, v3.x)
-	max_x := max(v1.x, v2.x, v3.x)
-	return {(max_x - min_x) * 0.5, 0}
-}
-
-top_right_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
-	min_x := min(v1.x, v2.x, v3.x)
-	max_x := max(v1.x, v2.x, v3.x)
-	return {max_x - min_x, 0}
-}
-
-left_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
-	min_y := min(v1.y, v2.y, v3.y)
-	max_y := max(v1.y, v2.y, v3.y)
-	return {0, (max_y - min_y) * 0.5}
-}
-
-right_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
-	bounds_min := Vec2{min(v1.x, v2.x, v3.x), min(v1.y, v2.y, v3.y)}
-	bounds_max := Vec2{max(v1.x, v2.x, v3.x), max(v1.y, v2.y, v3.y)}
-	return {bounds_max.x - bounds_min.x, (bounds_max.y - bounds_min.y) * 0.5}
-}
-
-bottom_left_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
-	min_y := min(v1.y, v2.y, v3.y)
-	max_y := max(v1.y, v2.y, v3.y)
-	return {0, max_y - min_y}
-}
-
-bottom_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
-	bounds_min := Vec2{min(v1.x, v2.x, v3.x), min(v1.y, v2.y, v3.y)}
-	bounds_max := Vec2{max(v1.x, v2.x, v3.x), max(v1.y, v2.y, v3.y)}
-	return {(bounds_max.x - bounds_min.x) * 0.5, bounds_max.y - bounds_min.y}
-}
-
-bottom_right_of_triangle :: #force_inline proc(v1, v2, v3: Vec2) -> Vec2 {
-	bounds_min := Vec2{min(v1.x, v2.x, v3.x), min(v1.y, v2.y, v3.y)}
-	bounds_max := Vec2{max(v1.x, v2.x, v3.x), max(v1.y, v2.y, v3.y)}
-	return bounds_max - bounds_min
-}

draw/tess/tess.odin

@@ -4,6 +4,7 @@ import "core:math"
 
 import draw ".."
 
+//INTERNAL
 SMOOTH_CIRCLE_ERROR_RATE :: 0.1
 
 auto_segments :: proc(radius: f32, arc_degrees: f32) -> int {
@@ -22,11 +23,18 @@ auto_segments :: proc(radius: f32, arc_degrees: f32) -> int {
 
 // Color is premultiplied: the tessellated fragment shader passes it through directly
 // and the blend state is ONE, ONE_MINUS_SRC_ALPHA.
-solid_vertex :: proc(position: draw.Vec2, color: draw.Color) -> draw.Vertex {
+//INTERNAL
-	return draw.Vertex{position = position, color = draw.premultiply_color(color)}
+solid_vertex :: proc(position: draw.Vec2, color: draw.Color) -> draw.Vertex_2D {
+	return draw.Vertex_2D{position = position, color = draw.premultiply_color(color)}
 }
 
-emit_rectangle :: proc(x, y, width, height: f32, color: draw.Color, vertices: []draw.Vertex, offset: int) {
+//INTERNAL
+emit_rectangle :: proc(
+	x, y, width, height: f32,
+	color: draw.Color,
+	vertices: []draw.Vertex_2D,
+	offset: int,
+) {
 	vertices[offset + 0] = solid_vertex({x, y}, color)
 	vertices[offset + 1] = solid_vertex({x + width, y}, color)
 	vertices[offset + 2] = solid_vertex({x + width, y + height}, color)
@@ -35,11 +43,12 @@ emit_rectangle :: proc(x, y, width, height: f32, color: draw.Color, vertices: []
 	vertices[offset + 5] = solid_vertex({x, y + height}, color)
 }
 
+//INTERNAL
 extrude_line :: proc(
 	start, end_pos: draw.Vec2,
 	thickness: f32,
 	color: draw.Color,
-	vertices: []draw.Vertex,
+	vertices: []draw.Vertex_2D,
 	offset: int,
 ) -> int {
 	direction := end_pos - start
@@ -69,7 +78,7 @@ extrude_line :: proc(
 // ----- Public draw -----
 
 pixel :: proc(layer: ^draw.Layer, pos: draw.Vec2, color: draw.Color) {
-	vertices: [6]draw.Vertex
+	vertices: [6]draw.Vertex_2D
 	emit_rectangle(pos[0], pos[1], 1, 1, color, vertices[:], 0)
 	draw.prepare_shape(layer, vertices[:])
 }
@@ -82,7 +91,7 @@ triangle :: proc(
 	rotation: f32 = 0,
 ) {
 	if !draw.needs_transform(origin, rotation) {
-		vertices := [3]draw.Vertex{solid_vertex(v1, color), solid_vertex(v2, color), solid_vertex(v3, color)}
+		vertices := [3]draw.Vertex_2D{solid_vertex(v1, color), solid_vertex(v2, color), solid_vertex(v3, color)}
 		draw.prepare_shape(layer, vertices[:])
 		return
 	}
@@ -91,7 +100,7 @@ triangle :: proc(
 	local_v1 := v1 - bounds_min
 	local_v2 := v2 - bounds_min
 	local_v3 := v3 - bounds_min
-	vertices := [3]draw.Vertex {
+	vertices := [3]draw.Vertex_2D {
 		solid_vertex(draw.apply_transform(transform, local_v1), color),
 		solid_vertex(draw.apply_transform(transform, local_v2), color),
 		solid_vertex(draw.apply_transform(transform, local_v3), color),
@@ -170,7 +179,7 @@ triangle_aa :: proc(
 	transparent := draw.BLANK
 
 	// 3 interior + 6 × 3 edge-quad = 21 vertices
-	vertices: [21]draw.Vertex
+	vertices: [21]draw.Vertex_2D
 
 	// Interior triangle
 	vertices[0] = solid_vertex(p0, color)
@@ -213,7 +222,7 @@ triangle_lines :: proc(
 	rotation: f32 = 0,
 	temp_allocator := context.temp_allocator,
 ) {
-	vertices := make([]draw.Vertex, 18, temp_allocator)
+	vertices := make([]draw.Vertex_2D, 18, temp_allocator)
 	defer delete(vertices, temp_allocator)
 	write_offset := 0
 
@@ -249,7 +258,7 @@ triangle_fan :: proc(
 
 	triangle_count := len(points) - 2
 	vertex_count := triangle_count * 3
-	vertices := make([]draw.Vertex, vertex_count, temp_allocator)
+	vertices := make([]draw.Vertex_2D, vertex_count, temp_allocator)
 	defer delete(vertices, temp_allocator)
 
 	if !draw.needs_transform(origin, rotation) {
@@ -289,7 +298,7 @@ triangle_strip :: proc(
 
 	triangle_count := len(points) - 2
 	vertex_count := triangle_count * 3
-	vertices := make([]draw.Vertex, vertex_count, temp_allocator)
+	vertices := make([]draw.Vertex_2D, vertex_count, temp_allocator)
 	defer delete(vertices, temp_allocator)
 
 	if !draw.needs_transform(origin, rotation) {

draw/text.odin

@@ -8,21 +8,25 @@ import sdl_ttf "vendor:sdl3/ttf"
 
 Font_Id :: u16
 
+//INTERNAL
 Font_Key :: struct {
 	id:   Font_Id,
 	size: u16,
 }
 
+//INTERNAL
 Cache_Source :: enum u8 {
 	Custom,
 	Clay,
 }
 
+//INTERNAL
 Cache_Key :: struct {
 	id:     u32,
 	source: Cache_Source,
 }
 
+//INTERNAL
 Text_Cache :: struct {
 	engine:     ^sdl_ttf.TextEngine,
 	font_bytes: [dynamic][]u8,
@@ -30,7 +34,8 @@ Text_Cache :: struct {
 	cache:      map[Cache_Key]^sdl_ttf.Text,
 }
 
-// Internal for fetching SDL TTF font pointer for rendering
+// Fetch SDL TTF font pointer for rendering.
+//INTERNAL
 get_font :: proc(id: Font_Id, size: u16) -> ^sdl_ttf.Font {
 	assert(int(id) < len(GLOB.text_cache.font_bytes), "Invalid font ID.")
 	key := Font_Key{id, size}
@@ -77,6 +82,7 @@ register_font :: proc(bytes: []u8) -> (id: Font_Id, ok: bool) #optional_ok {
 	return Font_Id(len(GLOB.text_cache.font_bytes) - 1), true
 }
 
+//INTERNAL
 Text :: struct {
 	sdl_text: ^sdl_ttf.Text,
 	position: Vec2,
@@ -89,7 +95,7 @@ Text :: struct {
 
 // Shared cache lookup/create/update logic used by both the `text` proc and the Clay render path.
 // Returns the cached (or newly created) TTF_Text pointer.
-@(private)
+//INTERNAL
 cache_get_or_update :: proc(key: Cache_Key, c_str: cstring, font: ^sdl_ttf.Font) -> ^sdl_ttf.Text {
 	existing, found := GLOB.text_cache.cache[key]
 	if !found {
@@ -268,7 +274,8 @@ clear_text_cache_entry :: proc(id: u32) {
 // ----- Internal cache lifecycle ------
 // ---------------------------------------------------------------------------------------------------------------------
 
-@(private, require_results)
+//INTERNAL
+@(require_results)
 init_text_cache :: proc(
 	device: ^sdl.GPUDevice,
 	allocator := context.allocator,
@@ -299,6 +306,7 @@ init_text_cache :: proc(
 	return text_cache, true
 }
 
+//INTERNAL
 destroy_text_cache :: proc() {
 	for _, font in GLOB.text_cache.sdl_fonts {
 		sdl_ttf.CloseFont(font)

draw/textures.odin

@@ -41,8 +41,7 @@ Texture_Desc :: struct {
 	kind:            Texture_Kind,
 }
 
-// Internal slot — not exported.
+//INTERNAL
-@(private)
 Texture_Slot :: struct {
 	gpu_texture: ^sdl.GPUTexture,
 	desc:        Texture_Desc,
@@ -319,8 +318,8 @@ texture_kind :: proc(id: Texture_Id) -> Texture_Kind {
 	return GLOB.texture_slots[u32(id)].desc.kind
 }
 
-// Internal: get the raw GPU texture pointer for binding during draw.
+// Get the raw GPU texture pointer for binding during draw.
-@(private)
+//INTERNAL
 texture_gpu_handle :: proc(id: Texture_Id) -> ^sdl.GPUTexture {
 	if id == INVALID_TEXTURE do return nil
 	idx := u32(id)
@@ -328,8 +327,8 @@ texture_gpu_handle :: proc(id: Texture_Id) -> ^sdl.GPUTexture {
 	return GLOB.texture_slots[idx].gpu_texture
 }
 
-// Deferred release (called from draw.end / clear_global)
+// Deferred release (called from end / clear_global).
-@(private)
+//INTERNAL
 process_pending_texture_releases :: proc() {
 	device := GLOB.device
 	for id in GLOB.pending_texture_releases {
@@ -346,7 +345,7 @@ process_pending_texture_releases :: proc() {
 	clear(&GLOB.pending_texture_releases)
 }
 
-@(private)
+//INTERNAL
 get_sampler :: proc(preset: Sampler_Preset) -> ^sdl.GPUSampler {
 	idx := int(preset)
 	if GLOB.samplers[idx] != nil do return GLOB.samplers[idx]
@@ -379,15 +378,15 @@ get_sampler :: proc(preset: Sampler_Preset) -> ^sdl.GPUSampler {
 	)
 	if sampler == nil {
 		log.errorf("Failed to create sampler preset %v: %s", preset, sdl.GetError())
-		return GLOB.pipeline_2d_base.sampler // fallback to existing default sampler
+		return GLOB.core_2d.sampler // fallback to existing default sampler
 	}
 
 	GLOB.samplers[idx] = sampler
 	return sampler
 }
 
-// Internal: destroy all sampler pool entries. Called from draw.destroy().
+// Destroy all sampler pool entries. Called from destroy().
-@(private)
+//INTERNAL
 destroy_sampler_pool :: proc() {
 	device := GLOB.device
 	for &s in GLOB.samplers {
@@ -398,8 +397,8 @@ destroy_sampler_pool :: proc() {
 	}
 }
 
-// Internal: destroy all registered textures. Called from draw.destroy().
+// Destroy all registered textures. Called from destroy().
-@(private)
+//INTERNAL
 destroy_all_textures :: proc() {
 	device := GLOB.device
 	for &slot in GLOB.texture_slots {