Tweaked general setup tracking allocator and added logger (#11)

Co-authored-by: Zachary Levy <zachary@sunforge.is>
Reviewed-on: #11

.zed/tasks.json

@@ -70,6 +70,11 @@
     "command": "odin run draw/examples -debug -out=out/debug/draw-examples -- hellope-custom",
     "cwd": "$ZED_WORKTREE_ROOT",
   },
+  {
+    "label": "Run draw textures example",
+    "command": "odin run draw/examples -debug -out=out/debug/draw-examples -- textures",
+    "cwd": "$ZED_WORKTREE_ROOT",
+  },
   {
     "label": "Run qrcode basic example",
     "command": "odin run qrcode/examples -debug -out=out/debug/qrcode-examples -- basic",

draw/README.md

@@ -47,68 +47,107 @@ primitives and effects can be added to the library without architectural changes
 
 ### Overview: three pipelines
 
-The 2D renderer will use three GPU pipelines, split by **register pressure compatibility** and
-**render-state requirements**:
+The 2D renderer uses three GPU pipelines, split by **register pressure** (main vs effects) and
+**render-pass structure** (everything vs backdrop):
 
-1. **Main pipeline** — shapes (SDF and tessellated) and text. Low register footprint (~18–22
-   registers per thread). Runs at high GPU occupancy. Handles 90%+ of all fragments in a typical
-   frame.
+1. **Main pipeline** — shapes (SDF and tessellated), text, and textured rectangles. Low register
+   footprint (~18–24 registers per thread). Runs at full GPU occupancy on every architecture.
+   Handles 90%+ of all fragments in a typical frame.
 
 2. **Effects pipeline** — drop shadows, inner shadows, outer glow, and similar ALU-bound blur
    effects. Medium register footprint (~48–60 registers). Each effects primitive includes the base
    shape's SDF so that it can draw both the effect and the shape in a single fragment pass, avoiding
-   redundant overdraw.
+   redundant overdraw. Separated from the main pipeline to protect main-pipeline occupancy on
+   low-end hardware (see register analysis below).
 
-3. **Backdrop-effects pipeline** — frosted glass, refraction, and any effect that samples the current
-   render target as input. High register footprint (~70–80 registers) and structurally requires a
-   `CopyGPUTextureToTexture` from the render target before drawing. Separated both for register
-   pressure and because the texture-copy requirement forces a render-pass-level state change.
+3. **Backdrop pipeline** — frosted glass, refraction, and any effect that samples the current render
+   target as input. Implemented as a multi-pass sequence (downsample, separable blur, composite),
+   where each individual pass has a low-to-medium register footprint (~15–40 registers). Separated
+   from the other pipelines because it structurally requires ending the current render pass and
+   copying the render target before any backdrop-sampling fragment can execute — a command-buffer-
+   level boundary that cannot be avoided regardless of shader complexity.
 
 A typical UI frame with no effects uses 1 pipeline bind and 0 switches. A frame with drop shadows
 uses 2 pipelines and 1 switch. A frame with shadows and frosted glass uses all 3 pipelines and 2
-switches plus 1 texture copy. At ~5μs per pipeline bind on modern APIs, worst-case switching overhead
-is under 0.15% of an 8.3ms (120 FPS) frame budget.
+switches plus 1 texture copy. At ~1–5μs per pipeline bind on modern APIs, worst-case switching
+overhead is negligible relative to an 8.3ms (120 FPS) frame budget.
 
 ### Why three pipelines, not one or seven
 
 The natural question is whether we should use a single unified pipeline (fewer state changes, simpler
 code) or many per-primitive-type pipelines (no branching overhead, lean per-shader register usage).
 
-The dominant cost factor is **GPU register pressure**, not pipeline switching overhead or fragment
-shader branching. A GPU shader core has a fixed register pool shared among all concurrent threads. The
-compiler allocates registers pessimistically based on the worst-case path through the shader. If the
-shader contains both a 20-register RRect SDF and a 72-register frosted-glass blur, _every_ fragment
-— even trivial RRects — is allocated 72 registers. This directly reduces **occupancy** (the number of
-warps that can run simultaneously), which reduces the GPU's ability to hide memory latency.
+#### Main/effects split: register pressure
 
-Concrete example on a modern NVIDIA SM with 65,536 registers:
+A GPU shader core has a fixed register pool shared among all concurrent threads. The compiler
+allocates registers pessimistically based on the worst-case path through the shader. If the shader
+contains both a 20-register RRect SDF and a 48-register drop-shadow blur, _every_ fragment — even
+trivial RRects — is allocated 48 registers. This directly reduces **occupancy** (the number of
+warps/wavefronts that can run simultaneously), which reduces the GPU's ability to hide memory
+latency.
 
-| Register allocation       | Max concurrent threads | Occupancy |
-| ------------------------- | ---------------------- | --------- |
-| 20 regs (RRect only)      | 3,276                  | ~100%     |
-| 48 regs (+ drop shadow)   | 1,365                  | ~42%      |
-| 72 regs (+ frosted glass) | 910                    | ~28%      |
+Each GPU architecture has a **register cliff** — a threshold above which occupancy starts dropping.
+Below the cliff, adding registers has zero occupancy cost.
 
-For a 4K frame (3840×2160) at 1.5× overdraw (~12.4M fragments), running all fragments at 28%
-occupancy instead of 100% roughly triples fragment shading time. At 4K this is severe: if the main
-pipeline's fragment work at full occupancy takes ~2ms, a single unified shader containing the glass
-branch would push it to ~6ms — consuming 72% of the 8.3ms budget available at 120 FPS and leaving
-almost nothing for CPU work, uploads, and presentation. This is a per-frame multiplier, not a
-per-primitive cost — it applies even when the heavy branch is never taken.
+On consumer Ampere/Ada GPUs (RTX 30xx/40xx, 65,536 regs/SM, max 1,536 threads/SM, cliff at ~43 regs):
 
-The three-pipeline split groups primitives by register footprint so that:
+| Register allocation     | Reg-limited threads | Actual (hw-capped) | Occupancy |
+| ----------------------- | ------------------- | ------------------ | --------- |
+| 20 regs (main pipeline) | 3,276               | 1,536              | 100%      |
+| 32 regs                 | 2,048               | 1,536              | 100%      |
+| 48 regs (effects)       | 1,365               | 1,365              | ~89%      |
 
-- Main pipeline (~20 regs): 90%+ of fragments run at near-full occupancy.
-- Effects pipeline (~55 regs): shadow/glow fragments run at moderate occupancy; unavoidable given the
-  blur math complexity.
-- Backdrop-effects pipeline (~75 regs): glass fragments run at low occupancy; also unavoidable, and
-  structurally separated anyway by the texture-copy requirement.
+On Volta/A100 GPUs (65,536 regs/SM, max 2,048 threads/SM, cliff at ~32 regs):
 
-This avoids the register-pressure tax of a single unified shader while keeping pipeline count minimal
-(3 vs. Zed GPUI's 7). The effects that drag occupancy down are isolated to the fragments that
-actually need them.
+| Register allocation     | Reg-limited threads | Actual (hw-capped) | Occupancy |
+| ----------------------- | ------------------- | ------------------ | --------- |
+| 20 regs (main pipeline) | 3,276               | 2,048              | 100%      |
+| 32 regs                 | 2,048               | 2,048              | 100%      |
+| 48 regs (effects)       | 1,365               | 1,365              | ~67%      |
 
-**Why not per-primitive-type pipelines (GPUI's approach)?** Zed's GPUI uses 7 separate shader pairs:
+On low-end mobile (ARM Mali Bifrost/Valhall, 64 regs/thread, cliff fixed at 32 regs):
+
+| Register allocation  | Occupancy                  |
+| -------------------- | -------------------------- |
+| 0–32 regs (main)     | 100% (full thread count)   |
+| 33–64 regs (effects) | ~50% (thread count halves) |
+
+Mali's cliff at 32 registers is the binding constraint. On desktop the occupancy difference between
+20 and 48 registers is modest (89–100%); on Mali it is a hard 2× throughput reduction. The
+main/effects split protects 90%+ of a frame's fragments (shapes, text, textures) from the effects
+pipeline's register cost.
+
+For the effects pipeline's drop-shadow shader — erf-approximation blur math with several texture
+fetches — 50% occupancy on Mali roughly halves throughput. At 4K with 1.5× overdraw (~12.4M
+fragments), a single unified shader containing the shadow branch would cost ~4ms instead of ~2ms on
+low-end mobile. This is a per-frame multiplier even when the heavy branch is never taken, because the
+compiler allocates registers for the worst-case path.
+
+All main-pipeline members (SDF shapes, tessellated geometry, text, textured rectangles) cluster at
+12–24 registers — below the cliff on every architecture — so unifying them costs nothing in
+occupancy.
+
+**Note on Apple M3+ GPUs:** Apple's M3 introduces Dynamic Caching (register file virtualization),
+which allocates registers at runtime based on actual usage rather than worst-case. This weakens the
+static register-pressure argument on M3 and later, but the split remains useful for isolating blur
+ALU complexity and keeping the backdrop texture-copy out of the main render pass.
+
+#### Backdrop split: render-pass structure
+
+The backdrop pipeline (frosted glass, refraction, mirror surfaces) is separated for a structural
+reason unrelated to register pressure. Before any backdrop-sampling fragment can execute, the current
+render target must be copied to a separate texture via `CopyGPUTextureToTexture` — a command-buffer-
+level operation that requires ending the current render pass. This boundary exists regardless of
+shader complexity and cannot be optimized away.
+
+The backdrop pipeline's individual shader passes (downsample, separable blur, composite) are
+register-light (~15–40 regs each), so merging them into the effects pipeline would cause no occupancy
+problem. But the render-pass boundary makes merging structurally impossible — effects draws happen
+inside the main render pass, backdrop draws happen inside their own bracketed pass sequence.
+
+#### Why not per-primitive-type pipelines (GPUI's approach)
+
+Zed's GPUI uses 7 separate shader pairs:
 quad, shadow, underline, monochrome sprite, polychrome sprite, path, surface. This eliminates all
 branching and gives each shader minimal register usage. Three concrete costs make this approach wrong
 for our use case:
@@ -120,7 +159,7 @@ typical UI frame with 15 scissors and 3–4 primitive kinds per scissor, per-kin
 ~45–60 draw calls and pipeline binds; our unified approach produces ~15–20 draw calls and 1–5
 pipeline binds. At ~5μs each for CPU-side command encoding on modern APIs, per-kind splitting adds
 375–500μs of CPU overhead per frame — **4.5–6% of an 8.3ms (120 FPS) budget** — with no
-compensating GPU-side benefit, because the register-pressure savings within the simple-SDF tier are
+compensating GPU-side benefit, because the register-pressure savings within the simple-SDF range are
 negligible (all members cluster at 12–22 registers).
 
 **Z-order preservation forces the API to expose layers.** With a single pipeline drawing all kinds
@@ -159,10 +198,10 @@ in submission order:
   ~60 boundary warps at ~80 extra instructions each), unified divergence costs ~13μs — still 3.5×
   cheaper than the pipeline-switching alternative.
 
-The split we _do_ perform (main / effects / backdrop-effects) is motivated by register-pressure tier
-boundaries where occupancy differences are catastrophic at 4K (see numbers above). Within a tier,
-unified is strictly better by every measure: fewer draw calls, simpler Z-order, lower CPU overhead,
-and negligible GPU-side branching cost.
+The split we _do_ perform (main / effects / backdrop) is motivated by register-pressure boundaries
+and structural render-pass requirements (see analysis above). Within a pipeline, unified is
+strictly better by every measure: fewer draw calls, simpler Z-order, lower CPU overhead, and
+negligible GPU-side branching cost.
 
 **References:**
 
@@ -172,6 +211,16 @@ and negligible GPU-side branching cost.
   https://github.com/zed-industries/zed/blob/cb6fc11/crates/gpui/src/platform/mac/shaders.metal
 - NVIDIA Nsight Graphics 2024.3 documentation on active-threads-per-warp and divergence analysis:
   https://developer.nvidia.com/blog/optimize-gpu-workloads-for-graphics-applications-with-nvidia-nsight-graphics/
+- NVIDIA Ampere GPU Architecture Tuning Guide — SM specs, max warps per SM (48 for cc 8.6, 64 for
+  cc 8.0), register file size (64K), occupancy factors:
+  https://docs.nvidia.com/cuda/ampere-tuning-guide/index.html
+- NVIDIA Ada GPU Architecture Tuning Guide — SM specs, max warps per SM (48 for cc 8.9):
+  https://docs.nvidia.com/cuda/ada-tuning-guide/index.html
+- CUDA Occupancy Calculation walkthrough (register allocation granularity, worked examples):
+  https://leimao.github.io/blog/CUDA-Occupancy-Calculation/
+- Apple M3 GPU architecture — Dynamic Caching (register file virtualization) eliminates static
+  worst-case register allocation, reducing the occupancy penalty for high-register shaders:
+  https://asplos.dev/wiki/m3-chip-explainer/gpu/index.html
 
 ### Why fragment shader branching is safe in this design
 
@@ -442,25 +491,40 @@ Wallace's variant) and vger-rs.
 - Vello's implementation of blurred rounded rectangle as a gradient type:
   https://github.com/linebender/vello/pull/665
 
-### Backdrop-effects pipeline
+### Backdrop pipeline
 
-The backdrop-effects pipeline handles effects that sample the current render target as input: frosted
-glass, refraction, mirror surfaces. It is structurally separated from the effects pipeline for two
-reasons:
+The backdrop pipeline handles effects that sample the current render target as input: frosted glass,
+refraction, mirror surfaces. It is separated from the effects pipeline for a structural reason, not
+register pressure.
 
-1. **Render-state requirement.** Before any backdrop-sampling fragment can run, the current render
-   target must be copied to a separate texture via `CopyGPUTextureToTexture`. This is a command-
-   buffer-level operation that cannot happen mid-render-pass. The copy naturally creates a pipeline
-   boundary.
+**Render-pass boundary.** Before any backdrop-sampling fragment can run, the current render target
+must be copied to a separate texture via `CopyGPUTextureToTexture`. This is a command-buffer-level
+operation that cannot happen mid-render-pass. The copy naturally creates a pipeline boundary that no
+amount of shader optimization can eliminate — it is a fundamental requirement of sampling a surface
+while also writing to it.
 
-2. **Register pressure.** Backdrop-sampling shaders read from a texture with Gaussian kernel weights
-   (multiple texture fetches per fragment), pushing register usage to ~70–80. Including this in the
-   effects pipeline would reduce occupancy for all shadow/glow fragments from ~30% to ~20%, costing
-   measurable throughput on the common case.
+**Multi-pass implementation.** Backdrop effects are implemented as separable multi-pass sequences
+(downsample → horizontal blur → vertical blur → composite), following the standard approach used by
+iOS `UIVisualEffectView`, Android `RenderEffect`, and Flutter's `BackdropFilter`. Each individual
+pass has a low-to-medium register footprint (~15–40 registers), well within the main pipeline's
+occupancy range. The multi-pass approach avoids the monolithic 70+ register shader that a single-pass
+Gaussian blur would require, making backdrop effects viable on low-end mobile GPUs (including
+Mali-G31 and VideoCore VI) where per-thread register limits are tight.
 
-The backdrop-effects pipeline binds a secondary sampler pointing at the captured backdrop texture. When
-no backdrop effects are present in a frame, this pipeline is never bound and the texture copy never
-happens — zero cost.
+**Bracketed execution.** All backdrop draws in a frame share a single bracketed region of the command
+buffer: end the current render pass, copy the render target, execute all backdrop sub-passes, then
+resume normal drawing. The entry/exit cost (texture copy + render-pass break) is paid once per frame
+regardless of how many backdrop effects are visible. When no backdrop effects are present, the bracket
+is never entered and the texture copy never happens — zero cost.
+
+**Why not split the backdrop sub-passes into separate pipelines?** The individual passes range from
+~15 to ~40 registers, which does cross Mali's 32-register cliff. However, the register-pressure argument
+that justifies the main/effects split does not apply here. The main/effects split protects the
+_common path_ (90%+ of frame fragments) from the uncommon path's register cost. Inside the backdrop
+pipeline there is no common-vs-uncommon distinction — if backdrop effects are active, every sub-pass
+runs; if not, none run. The backdrop pipeline either executes as a complete unit or not at all.
+Additionally, backdrop effects cover a small fraction of the frame's total fragments (~5% at typical
+UI scales), so the occupancy variation within the bracket has negligible impact on frame time.
 
 ### Vertex layout
 
@@ -483,19 +547,21 @@ The `Primitive` struct for SDF shapes lives in the storage buffer, not in vertex
 
 ```
 Primitive :: struct {
-    kind:   Shape_Kind,     //  0: enum u8
-    flags:  Shape_Flags,    //  1: bit_set[Shape_Flag; u8]
-    _pad:   u16,            //  2: reserved
-    bounds: [4]f32,         //  4: min_x, min_y, max_x, max_y
-    color:  Color,          // 20: u8x4
-    _pad2:  [3]u8,          // 24: alignment
-    params: Shape_Params,   // 28: raw union, 32 bytes
+    bounds:     [4]f32,         //  0: min_x, min_y, max_x, max_y
+    color:      Color,          // 16: u8x4, unpacked in shader via unpackUnorm4x8
+    kind_flags: u32,            // 20: (kind as u32) | (flags as u32 << 8)
+    rotation:   f32,            // 24: shader self-rotation in radians
+    _pad:       f32,            // 28: alignment
+    params:     Shape_Params,   // 32: raw union, 32 bytes (two vec4s of shape-specific data)
+    uv_rect:    [4]f32,         // 64: texture UV sub-region (u_min, v_min, u_max, v_max)
 }
-// Total: 60 bytes (padded to 64 for GPU alignment)
+// Total: 80 bytes (std430 aligned)
 ```
 
 `Shape_Params` is a `#raw_union` with named variants per shape kind (`rrect`, `circle`, `segment`,
-etc.), ensuring type safety on the CPU side and zero-cost reinterpretation on the GPU side.
+etc.), ensuring type safety on the CPU side and zero-cost reinterpretation on the GPU side. The
+`uv_rect` field is used by textured SDF primitives (Shape_Flag.Textured); non-textured primitives
+leave it zeroed.
 
 ### Draw submission order
 
@@ -506,7 +572,7 @@ Within each scissor region, draws are issued in submission order to preserve the
 2. Bind **main pipeline, tessellated mode** → draw all queued tessellated vertices (non-indexed for
    shapes, indexed for text). Pipeline state unchanged from today.
 3. Bind **main pipeline, SDF mode** → draw all queued SDF primitives (instanced, one draw call).
-4. If backdrop effects are present: copy render target, bind **backdrop-effects pipeline** → draw
+4. If backdrop effects are present: copy render target, bind **backdrop pipeline** → draw
    backdrop primitives.
 
 The exact ordering within a scissor may be refined based on actual Z-ordering requirements. The key
@@ -539,12 +605,180 @@ changes.
 - Valve's original SDF text rendering paper (SIGGRAPH 2007):
   https://steamcdn-a.akamaihd.net/apps/valve/2007/SIGGRAPH2007_AlphaTestedMagnification.pdf
 
+### Textures
+
+Textures plug into the existing main pipeline — no additional GPU pipeline, no shader rewrite. The
+work is a resource layer (registration, upload, sampling, lifecycle) plus two textured-draw procs
+that route into the existing tessellated and SDF paths respectively.
+
+#### Why draw owns registered textures
+
+A texture's GPU resource (the `^sdl.GPUTexture`, transfer buffer, shader resource view) is created
+and destroyed by draw. The user provides raw bytes and a descriptor at registration time; draw
+uploads synchronously and returns an opaque `Texture_Id` handle. The user can free their CPU-side
+bytes immediately after `register_texture` returns.
+
+This follows the model used by the RAD Debugger's render layer (`src/render/render_core.h` in
+EpicGamesExt/raddebugger, MIT license), where `r_tex2d_alloc` takes `(kind, size, format, data)`
+and returns an opaque handle that the renderer owns and releases. The single-owner model eliminates
+an entire class of lifecycle bugs (double-free, use-after-free across subsystems, unclear cleanup
+responsibility) that dual-ownership designs introduce.
+
+If advanced interop is ever needed (e.g., a future 3D pipeline or compute shader sharing the same
+GPU texture), the clean extension is a borrowed-reference accessor (`get_gpu_texture(id)`) that
+returns the underlying handle without transferring ownership. This is purely additive and does not
+require changing the registration API.
+
+#### Why `Texture_Kind` exists
+
+`Texture_Kind` (Static / Dynamic / Stream) is a driver hint for update frequency, adopted from the
+RAD Debugger's `R_ResourceKind`. It maps directly to SDL3 GPU usage patterns:
+
+- **Static**: uploaded once, never changes. Covers QR codes, decoded PNGs, icons — the 90% case.
+- **Dynamic**: updatable via `update_texture_region`. Covers font atlas growth, procedural updates.
+- **Stream**: frequent full re-uploads. Covers video playback, per-frame procedural generation.
+
+This costs one byte in the descriptor and lets the backend pick optimal memory placement without a
+future API change.
+
+#### Why samplers are per-draw, not per-texture
+
+A sampler describes how to filter and address a texture during sampling — nearest vs bilinear, clamp
+vs repeat. This is a property of the _draw_, not the texture. The same QR code texture should be
+sampled with `Nearest_Clamp` when displayed at native resolution but could reasonably be sampled
+with `Linear_Clamp` in a zoomed-out thumbnail. The same icon atlas might be sampled with
+`Nearest_Clamp` for pixel art or `Linear_Clamp` for smooth scaling.
+
+The RAD Debugger follows this pattern: `R_BatchGroup2DParams` carries `tex_sample_kind` alongside
+the texture handle, chosen per batch group at draw time. We do the same — `Sampler_Preset` is a
+parameter on the draw procs, not a field on `Texture_Desc`.
+
+Internally, draw keeps a small pool of pre-created `^sdl.GPUSampler` objects (one per preset,
+lazily initialized). Sub-batch coalescing keys on `(kind, texture_id, sampler_preset)` — draws
+with the same texture but different samplers produce separate draw calls, which is correct.
+
+#### Textured draw procs
+
+Textured rectangles route through the existing SDF path via `draw.rectangle_texture` and
+`draw.rectangle_texture_corners`, mirroring `draw.rectangle` and `draw.rectangle_corners` exactly —
+same parameters, same naming — with the color parameter replaced by a texture ID plus an optional
+tint.
+
+An earlier iteration of this design considered a separate tessellated `draw.texture` proc for
+"simple" fullscreen quads, on the theory that the tessellated path's lower register count (~16 regs
+vs ~24 for the SDF textured branch) would improve occupancy at large fragment counts. Applying the
+register-pressure analysis from the pipeline-strategy section above shows this is wrong: both 16 and
+24 registers are well below the register cliff (~43 regs on consumer Ampere/Ada, ~32 on Volta/A100),
+so both run at 100% occupancy. The remaining ALU difference (~15 extra instructions for the SDF
+evaluation) amounts to ~20μs at 4K — below noise. Meanwhile, splitting into a separate pipeline
+would add ~1–5μs per pipeline bind on the CPU side per scissor, matching or exceeding the GPU-side
+savings. Within the main pipeline, unified remains strictly better.
+
+The naming convention follows the existing shape API: `rectangle_texture` and
+`rectangle_texture_corners` sit alongside `rectangle` and `rectangle_corners`, mirroring the
+`rectangle_gradient` / `circle_gradient` pattern where the shape is the primary noun and the
+modifier (gradient, texture) is secondary. This groups related procs together in autocomplete
+(`rectangle_*`) and reads as natural English ("draw a rectangle with a texture").
+
+Future per-shape texture variants (`circle_texture`, `ellipse_texture`, `polygon_texture`) are
+reserved by this naming convention and require only a `Shape_Flag.Textured` bit plus a small
+per-shape UV mapping function in the fragment shader. These are additive.
+
+#### What SDF anti-aliasing does and does not do for textured draws
+
+The SDF path anti-aliases the **shape's outer silhouette** — rounded-corner edges, rotated edges,
+stroke outlines. It does not anti-alias or sharpen the texture content. Inside the shape, fragments
+sample through the chosen `Sampler_Preset`, and image quality is whatever the sampler produces from
+the source texels. A low-resolution texture displayed at a large size shows bilinear blur regardless
+of which draw proc is used. This matches the current text-rendering model, where glyph sharpness
+depends on how closely the display size matches the SDL_ttf atlas's rasterized size.
+
+#### Fit modes are a computation layer, not a renderer concept
+
+Standard image-fit behaviors (stretch, fill/cover, fit/contain, tile, center) are expressed as UV
+sub-region computations on top of the `uv_rect` parameter that both textured-draw procs accept. The
+renderer has no knowledge of fit modes — it samples whatever UV region it is given.
+
+A `fit_params` helper computes the appropriate `uv_rect`, sampler preset, and (for letterbox/fit
+mode) shrunken inner rect from a `Fit_Mode` enum, the target rect, and the texture's pixel size.
+Users who need custom UV control (sprite atlas sub-regions, UV animation, nine-patch slicing) skip
+the helper and compute `uv_rect` directly. This keeps the renderer primitive minimal while making
+the common cases convenient.
+
+#### Deferred release
+
+`unregister_texture` does not immediately release the GPU texture. It queues the slot for release at
+the end of the current frame, after `SubmitGPUCommandBuffer` has handed work to the GPU. This
+prevents a race condition where a texture is freed while the GPU is still sampling from it in an
+already-submitted command buffer. The same deferred-release pattern is applied to `clear_text_cache`
+and `clear_text_cache_entry`, fixing a pre-existing latent bug where destroying a cached
+`^sdl_ttf.Text` mid-frame could free an atlas texture still referenced by in-flight draw batches.
+
+This pattern is standard in production renderers — the RAD Debugger's `r_tex2d_release` queues
+textures onto a free list that is processed in `r_end_frame`, not at the call site.
+
+#### Clay integration
+
+Clay's `RenderCommandType.Image` is handled by dereferencing `imageData: rawptr` as a pointer to a
+`Clay_Image_Data` struct containing a `Texture_Id`, `Fit_Mode`, and tint color. Routing mirrors the
+existing rectangle handling: zero `cornerRadius` dispatches to `draw.texture` (tessellated), nonzero
+dispatches to `draw.rectangle_texture_corners` (SDF). A `fit_params` call computes UVs from the fit
+mode before dispatch.
+
+#### Deferred features
+
+The following are plumbed in the descriptor but not implemented in phase 1:
+
+- **Mipmaps**: `Texture_Desc.mip_levels` field exists; generation via SDL3 deferred.
+- **Compressed formats**: `Texture_Desc.format` accepts BC/ASTC; upload path deferred.
+- **Render-to-texture**: `Texture_Desc.usage` accepts `.COLOR_TARGET`; render-pass refactor deferred.
+- **3D textures, arrays, cube maps**: `Texture_Desc.type` and `depth_or_layers` fields exist.
+- **Additional samplers**: anisotropic, trilinear, clamp-to-border — additive enum values.
+- **Atlas packing**: internal optimization for sub-batch coalescing; invisible to callers.
+- **Per-shape texture variants**: `circle_texture`, `ellipse_texture`, etc. — reserved by naming.
+
+**References:**
+
+- RAD Debugger render layer (ownership model, deferred release, sampler-at-draw-time):
+  https://github.com/EpicGamesExt/raddebugger — `src/render/render_core.h`, `src/render/d3d11/render_d3d11.c`
+- Casey Muratori, Handmade Hero day 472 — texture handling as a renderer-owned resource concern,
+  atlases as a separate layer above the renderer.
+
 ## 3D rendering
 
 3D pipeline architecture is under consideration and will be documented separately. The current
 expectation is that 3D rendering will use dedicated pipelines (separate from the 2D pipelines)
 sharing GPU resources (textures, samplers, command buffer lifecycle) with the 2D renderer.
 
+## Multi-window support
+
+The renderer currently assumes a single window via the global `GLOB` state. Multi-window support is
+deferred but anticipated. When revisited, the RAD Debugger's bucket + pass-list model
+(`src/draw/draw.h`, `src/draw/draw.c` in EpicGamesExt/raddebugger) is worth studying as a reference.
+
+RAD separates draw submission from rendering via **buckets**. A `DR_Bucket` is an explicit handle
+that accumulates an ordered list of render passes (`R_PassList`). The user creates a bucket, pushes
+it onto a thread-local stack, issues draw calls (which target the top-of-stack bucket), then submits
+the bucket to a specific window. Multiple buckets can exist simultaneously — one per window, or one
+per UI panel that gets composited into a parent bucket via `dr_sub_bucket`. Implicit draw parameters
+(clip rect, 2D transform, sampler mode, transparency) are managed via push/pop stacks scoped to each
+bucket, so different windows can have independent clip and transform state without interference.
+
+The key properties this gives RAD:
+
+- **Per-window isolation.** Each window builds its own bucket with its own pass list and state stacks.
+  No global contention.
+- **Thread-parallel building.** Each thread has its own draw context and arena. Multiple threads can
+  build buckets concurrently, then submit them to the render backend sequentially.
+- **Compositing.** A pre-built bucket (e.g., a tooltip or overlay) can be injected into another
+  bucket with a transform applied, without rebuilding its draw calls.
+
+For our library, the likely adaptation would be replacing the single `GLOB` with a per-window draw
+context that users create and pass to `begin`/`end`, while keeping the explicit-parameter draw call
+style rather than adopting RAD's implicit state stacks. Texture and sampler resources would remain
+global (shared across windows), with only the per-frame staging buffers and layer/scissor state
+becoming per-context.
+
 ## Building shaders
 
 GLSL shader sources live in `shaders/source/`. Compiled outputs (SPIR-V and Metal Shading Language)

draw/draw.odin

@@ -63,15 +63,17 @@ Rectangle :: struct {
 }
 
 Sub_Batch_Kind :: enum u8 {
-	Shapes, // non-indexed, white texture, mode 0
+	Shapes, // non-indexed, white texture or user texture, mode 0
 	Text, // indexed, atlas texture, mode 0
-	SDF, // instanced unit quad, white texture, mode 1
+	SDF, // instanced unit quad, white texture or user texture, mode 1
 }
 
 Sub_Batch :: struct {
-	kind:   Sub_Batch_Kind,
-	offset: u32, // Shapes: vertex offset; Text: text_batch index; SDF: primitive index
-	count:  u32, // Shapes: vertex count; Text: always 1; SDF: primitive count
+	kind:       Sub_Batch_Kind,
+	offset:     u32, // Shapes: vertex offset; Text: text_batch index; SDF: primitive index
+	count:      u32, // Shapes: vertex count; Text: always 1; SDF: primitive count
+	texture_id: Texture_Id,
+	sampler:    Sampler_Preset,
 }
 
 Layer :: struct {
@@ -95,35 +97,60 @@ Scissor :: struct {
 GLOB: Global
 
 Global :: struct {
-	odin_context:      runtime.Context,
-	pipeline_2d_base:  Pipeline_2D_Base,
-	text_cache:        Text_Cache,
-	layers:            [dynamic]Layer,
-	scissors:          [dynamic]Scissor,
-	tmp_shape_verts:   [dynamic]Vertex,
-	tmp_text_verts:    [dynamic]Vertex,
-	tmp_text_indices:  [dynamic]c.int,
-	tmp_text_batches:  [dynamic]TextBatch,
-	tmp_primitives:    [dynamic]Primitive,
-	tmp_sub_batches:   [dynamic]Sub_Batch,
-	tmp_uncached_text: [dynamic]^sdl_ttf.Text, // Uncached TTF_Text objects to destroy after end()
-	clay_memory:       [^]u8,
-	msaa_texture:      ^sdl.GPUTexture,
-	curr_layer_index:  uint,
-	max_layers:        int,
-	max_scissors:      int,
-	max_shape_verts:   int,
-	max_text_verts:    int,
-	max_text_indices:  int,
-	max_text_batches:  int,
-	max_primitives:    int,
-	max_sub_batches:   int,
-	dpi_scaling:       f32,
-	msaa_width:        u32,
-	msaa_height:       u32,
-	sample_count:      sdl.GPUSampleCount,
-	clay_z_index:      i16,
-	cleared:           bool,
+	// -- Per-frame staging (hottest — touched by every prepare/upload/clear cycle) --
+	tmp_shape_verts:          [dynamic]Vertex, // Tessellated shape vertices staged for GPU upload.
+	tmp_text_verts:           [dynamic]Vertex, // Text vertices 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_primitives:           [dynamic]Primitive, // SDF primitives staged for GPU storage buffer upload.
+	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.
+	layers:                   [dynamic]Layer, // Draw layers, each with its own scissor stack.
+	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.
+	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.
+	cleared:                  bool, // Whether the render target has been cleared this frame.
+
+	// -- Pipeline (accessed every draw_layer call) --
+	pipeline_2d_base:         Pipeline_2D_Base, // The unified 2D GPU pipeline (shaders, buffers, samplers).
+	device:                   ^sdl.GPUDevice, // GPU device handle, stored at init.
+	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_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_free_list:        [dynamic]u32, // Recycled slot indices available for reuse.
+
+	// -- MSAA (once per frame in end()) --
+	msaa_texture:             ^sdl.GPUTexture, // Intermediate render target for multi-sample resolve.
+	msaa_width:               u32, // Cached width to detect when MSAA texture needs recreation.
+	msaa_height:              u32, // Cached height to detect when MSAA texture needs recreation.
+	sample_count:             sdl.GPUSampleCount, // Sample count chosen at init (._1 means MSAA disabled).
+
+	// -- Clay (once per frame in prepare_clay_batch) --
+	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.
+
+	// -- Resize tracking (cold — checked once per frame in resize_global) --
+	max_layers:               int, // High-water marks for dynamic array shrink heuristic.
+	max_scissors:             int,
+	max_shape_verts:          int,
+	max_text_verts:           int,
+	max_text_indices:         int,
+	max_text_batches:         int,
+	max_primitives:           int,
+	max_sub_batches:          int,
+
+	// -- Init-only (coldest — set once at init, never written again) --
+	odin_context:             runtime.Context, // Odin context captured at init for use in callbacks.
 }
 
 Init_Options :: struct {
@@ -168,22 +195,30 @@ init :: proc(
 	}
 
 	GLOB = Global {
-		layers            = make([dynamic]Layer, 0, INITIAL_LAYER_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_text_verts    = make([dynamic]Vertex, 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_primitives    = make([dynamic]Primitive, 0, BUFFER_INIT_SIZE, allocator = allocator),
-		tmp_sub_batches   = make([dynamic]Sub_Batch, 0, BUFFER_INIT_SIZE, allocator = allocator),
-		tmp_uncached_text = 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),
-		sample_count      = resolved_sample_count,
-		pipeline_2d_base  = pipeline,
-		text_cache        = text_cache,
+		layers                   = make([dynamic]Layer, 0, INITIAL_LAYER_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_text_verts           = make([dynamic]Vertex, 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_primitives           = make([dynamic]Primitive, 0, BUFFER_INIT_SIZE, allocator = allocator),
+		tmp_sub_batches          = make([dynamic]Sub_Batch, 0, BUFFER_INIT_SIZE, allocator = allocator),
+		tmp_uncached_text        = make([dynamic]^sdl_ttf.Text, 0, 16, allocator = allocator),
+		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),
+		sample_count             = resolved_sample_count,
+		pipeline_2d_base         = pipeline,
+		text_cache               = text_cache,
 	}
+
+	// Reserve slot 0 for INVALID_TEXTURE
+	append(&GLOB.texture_slots, Texture_Slot{})
 	log.debug("Window DPI scaling:", GLOB.dpi_scaling)
 	arena := clay.CreateArenaWithCapacityAndMemory(min_memory_size, GLOB.clay_memory)
 	window_width, window_height: c.int
@@ -230,12 +265,23 @@ destroy :: proc(device: ^sdl.GPUDevice, allocator := context.allocator) {
 	if GLOB.msaa_texture != nil {
 		sdl.ReleaseGPUTexture(device, GLOB.msaa_texture)
 	}
+	process_pending_texture_releases()
+	destroy_all_textures()
+	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_base(device, &GLOB.pipeline_2d_base)
 	destroy_text_cache()
 }
 
 // Internal
 clear_global :: proc() {
+	// Process deferred texture releases from the previous frame
+	process_pending_texture_releases()
+	// Process deferred text releases from the previous frame
+	for ttf_text in GLOB.pending_text_releases do sdl_ttf.DestroyText(ttf_text)
+	clear(&GLOB.pending_text_releases)
+
 	GLOB.curr_layer_index = 0
 	GLOB.clay_z_index = 0
 	GLOB.cleared = false
@@ -265,6 +311,7 @@ measure_text_clay :: proc "c" (
 	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())
@@ -454,15 +501,24 @@ append_or_extend_sub_batch :: proc(
 	kind: Sub_Batch_Kind,
 	offset: u32,
 	count: u32,
+	texture_id: Texture_Id = INVALID_TEXTURE,
+	sampler: Sampler_Preset = .Linear_Clamp,
 ) {
 	if scissor.sub_batch_len > 0 {
 		last := &GLOB.tmp_sub_batches[scissor.sub_batch_start + scissor.sub_batch_len - 1]
-		if last.kind == kind && kind != .Text && last.offset + last.count == offset {
+		if last.kind == kind &&
+		   kind != .Text &&
+		   last.offset + last.count == offset &&
+		   last.texture_id == texture_id &&
+		   last.sampler == sampler {
 			last.count += count
 			return
 		}
 	}
-	append(&GLOB.tmp_sub_batches, Sub_Batch{kind = kind, offset = offset, count = count})
+	append(
+		&GLOB.tmp_sub_batches,
+		Sub_Batch{kind = kind, offset = offset, count = count, texture_id = texture_id, sampler = sampler},
+	)
 	scissor.sub_batch_len += 1
 	layer.sub_batch_len += 1
 }
@@ -502,6 +558,7 @@ prepare_clay_batch :: proc(
 	mouse_wheel_delta: [2]f32,
 	frame_time: f32 = 0,
 	custom_draw: Custom_Draw = nil,
+	temp_allocator := context.temp_allocator,
 ) {
 	mouse_pos: [2]f32
 	mouse_flags := sdl.GetMouseState(&mouse_pos.x, &mouse_pos.y)
@@ -541,7 +598,8 @@ prepare_clay_batch :: proc(
 		case clay.RenderCommandType.Text:
 			render_data := render_command.renderData.text
 			txt := string(render_data.stringContents.chars[:render_data.stringContents.length])
-			c_text := strings.clone_to_cstring(txt, context.temp_allocator)
+			c_text := strings.clone_to_cstring(txt, temp_allocator)
+			defer delete(c_text, temp_allocator)
 			// Clay render-command IDs are derived via Clay's internal HashNumber (Jenkins-family)
 			// and namespaced with .Clay so they can never collide with user-provided custom text IDs.
 			sdl_text := cache_get_or_update(
@@ -551,6 +609,46 @@ prepare_clay_batch :: proc(
 			)
 			prepare_text(layer, Text{sdl_text, {bounds.x, bounds.y}, color_from_clay(render_data.textColor)})
 		case clay.RenderCommandType.Image:
+			render_data := render_command.renderData.image
+			if render_data.imageData == nil do continue
+			img_data := (^Clay_Image_Data)(render_data.imageData)^
+			cr := render_data.cornerRadius
+			radii := [4]f32{cr.topLeft, cr.topRight, cr.bottomRight, cr.bottomLeft}
+
+			// Background color behind the image (Clay allows it)
+			bg := color_from_clay(render_data.backgroundColor)
+			if bg[3] > 0 {
+				if radii == {0, 0, 0, 0} {
+					rectangle(layer, bounds, bg)
+				} else {
+					rectangle_corners(layer, bounds, radii, bg)
+				}
+			}
+
+			// Compute fit UVs
+			uv, sampler, inner := fit_params(img_data.fit, bounds, img_data.texture_id)
+
+			// Draw the image — route by cornerRadius
+			if radii == {0, 0, 0, 0} {
+				rectangle_texture(
+					layer,
+					inner,
+					img_data.texture_id,
+					tint = img_data.tint,
+					uv_rect = uv,
+					sampler = sampler,
+				)
+			} else {
+				rectangle_texture_corners(
+					layer,
+					inner,
+					radii,
+					img_data.texture_id,
+					tint = img_data.tint,
+					uv_rect = uv,
+					sampler = sampler,
+				)
+			}
 		case clay.RenderCommandType.ScissorStart:
 			if bounds.width == 0 || bounds.height == 0 do continue
 

draw/draw_qr/draw_qr.odin

@@ -0,0 +1,175 @@
+package draw_qr
+
+import draw ".."
+import "../../qrcode"
+
+// Returns the number of bytes to_texture will write for the given encoded
+// QR buffer. Equivalent to size*size*4 where size = qrcode.get_size(qrcode_buf).
+texture_size :: #force_inline proc(qrcode_buf: []u8) -> int {
+	size := qrcode.get_size(qrcode_buf)
+	return size * size * 4
+}
+
+// Decodes an encoded QR buffer into tightly-packed RGBA pixel data written to
+// texture_buf. No allocations, no GPU calls. Returns the Texture_Desc the
+// caller should pass to draw.register_texture alongside texture_buf.
+//
+// Returns ok=false when:
+//   - qrcode_buf is invalid (qrcode.get_size returns 0).
+//   - texture_buf is smaller than to_texture_size(qrcode_buf).
+@(require_results)
+to_texture :: proc(
+	qrcode_buf: []u8,
+	texture_buf: []u8,
+	dark: draw.Color = draw.BLACK,
+	light: draw.Color = draw.WHITE,
+) -> (
+	desc: draw.Texture_Desc,
+	ok: bool,
+) {
+	size := qrcode.get_size(qrcode_buf)
+	if size == 0 do return {}, false
+	if len(texture_buf) < size * size * 4 do return {}, false
+
+	for y in 0 ..< size {
+		for x in 0 ..< size {
+			i := (y * size + x) * 4
+			c := dark if qrcode.get_module(qrcode_buf, x, y) else light
+			texture_buf[i + 0] = c[0]
+			texture_buf[i + 1] = c[1]
+			texture_buf[i + 2] = c[2]
+			texture_buf[i + 3] = c[3]
+		}
+	}
+
+	return draw.Texture_Desc {
+			width = u32(size),
+			height = u32(size),
+			depth_or_layers = 1,
+			type = .D2,
+			format = .R8G8B8A8_UNORM,
+			usage = {.SAMPLER},
+			mip_levels = 1,
+			kind = .Static,
+		},
+		true
+}
+
+// Allocates pixel buffer via temp_allocator, decodes qrcode_buf into it, and
+// registers with the GPU. The pixel allocation is freed before return.
+//
+// Returns ok=false when:
+//   - qrcode_buf is invalid (qrcode.get_size returns 0).
+//   - temp_allocator fails to allocate the pixel buffer.
+//   - GPU texture registration fails.
+@(require_results)
+register_texture_from_raw :: proc(
+	qrcode_buf: []u8,
+	dark: draw.Color = draw.BLACK,
+	light: draw.Color = draw.WHITE,
+	temp_allocator := context.temp_allocator,
+) -> (
+	texture: draw.Texture_Id,
+	ok: bool,
+) {
+	tex_size := texture_size(qrcode_buf)
+	if tex_size == 0 do return draw.INVALID_TEXTURE, false
+
+	pixels, alloc_err := make([]u8, tex_size, temp_allocator)
+	if alloc_err != nil do return draw.INVALID_TEXTURE, false
+	defer delete(pixels, temp_allocator)
+
+	desc := to_texture(qrcode_buf, pixels, dark, light) or_return
+	return draw.register_texture(desc, pixels)
+}
+
+// Encodes text as a QR Code and registers the result as an RGBA texture.
+//
+// Returns ok=false when:
+//   - temp_allocator fails to allocate.
+//   - The text cannot fit in any version within [min_version, max_version] at the given ECL.
+//   - GPU texture registration fails.
+@(require_results)
+register_texture_from_text :: proc(
+	text: string,
+	ecl: qrcode.Ecc = .Low,
+	min_version: int = qrcode.VERSION_MIN,
+	max_version: int = qrcode.VERSION_MAX,
+	mask: Maybe(qrcode.Mask) = nil,
+	boost_ecl: bool = true,
+	dark: draw.Color = draw.BLACK,
+	light: draw.Color = draw.WHITE,
+	temp_allocator := context.temp_allocator,
+) -> (
+	texture: draw.Texture_Id,
+	ok: bool,
+) {
+	qrcode_buf, alloc_err := make([]u8, qrcode.buffer_len_for_version(max_version), temp_allocator)
+	if alloc_err != nil do return draw.INVALID_TEXTURE, false
+	defer delete(qrcode_buf, temp_allocator)
+
+	qrcode.encode_auto(
+		text,
+		qrcode_buf,
+		ecl,
+		min_version,
+		max_version,
+		mask,
+		boost_ecl,
+		temp_allocator,
+	) or_return
+
+	return register_texture_from_raw(qrcode_buf, dark, light, temp_allocator)
+}
+
+// Encodes arbitrary binary data as a QR Code and registers the result as an RGBA texture.
+//
+// Returns ok=false when:
+//   - temp_allocator fails to allocate.
+//   - The payload cannot fit in any version within [min_version, max_version] at the given ECL.
+//   - GPU texture registration fails.
+@(require_results)
+register_texture_from_binary :: proc(
+	bin_data: []u8,
+	ecl: qrcode.Ecc = .Low,
+	min_version: int = qrcode.VERSION_MIN,
+	max_version: int = qrcode.VERSION_MAX,
+	mask: Maybe(qrcode.Mask) = nil,
+	boost_ecl: bool = true,
+	dark: draw.Color = draw.BLACK,
+	light: draw.Color = draw.WHITE,
+	temp_allocator := context.temp_allocator,
+) -> (
+	texture: draw.Texture_Id,
+	ok: bool,
+) {
+	qrcode_buf, alloc_err := make([]u8, qrcode.buffer_len_for_version(max_version), temp_allocator)
+	if alloc_err != nil do return draw.INVALID_TEXTURE, false
+	defer delete(qrcode_buf, temp_allocator)
+
+	qrcode.encode_auto(
+		bin_data,
+		qrcode_buf,
+		ecl,
+		min_version,
+		max_version,
+		mask,
+		boost_ecl,
+		temp_allocator,
+	) or_return
+
+	return register_texture_from_raw(qrcode_buf, dark, light, temp_allocator)
+}
+
+register_texture_from :: proc {
+	register_texture_from_text,
+	register_texture_from_binary
+}
+
+// Default fit=.Fit preserves the QR's square aspect; override as needed.
+clay_image :: #force_inline proc(
+	texture: draw.Texture_Id,
+	tint: draw.Color = draw.WHITE,
+) -> draw.Clay_Image_Data {
+	return draw.clay_image_data(texture, fit = .Fit, tint = tint)
+}

draw/examples/examples.odin

@@ -1,19 +1,18 @@
 package examples
 
 import "core:fmt"
+import "core:log"
 import "core:mem"
 import "core:os"
 
 main :: proc() {
-	//----- Tracking allocator ----------------------------------
+	//----- General setup ----------------------------------
 	{
-		tracking_temp_allocator := false
 		// Temp
 		track_temp: mem.Tracking_Allocator
-		if tracking_temp_allocator {
-			mem.tracking_allocator_init(&track_temp, context.temp_allocator)
-			context.temp_allocator = mem.tracking_allocator(&track_temp)
-		}
+		mem.tracking_allocator_init(&track_temp, context.temp_allocator)
+		context.temp_allocator = mem.tracking_allocator(&track_temp)
+
 		// Default
 		track: mem.Tracking_Allocator
 		mem.tracking_allocator_init(&track, context.allocator)
@@ -22,18 +21,10 @@ main :: proc() {
 		// This could be fine for some global state or it could be a memory leak.
 		defer {
 			// Temp allocator
-			if tracking_temp_allocator {
-				if len(track_temp.allocation_map) > 0 {
-					fmt.eprintf("=== %v allocations not freed - temp allocator: ===\n", len(track_temp.allocation_map))
-					for _, entry in track_temp.allocation_map {
-						fmt.eprintf("- %v bytes @ %v\n", entry.size, entry.location)
-					}
-				}
-				if len(track_temp.bad_free_array) > 0 {
-					fmt.eprintf("=== %v incorrect frees - temp allocator: ===\n", len(track_temp.bad_free_array))
-					for entry in track_temp.bad_free_array {
-						fmt.eprintf("- %p @ %v\n", entry.memory, entry.location)
-					}
+			if len(track_temp.bad_free_array) > 0 {
+				fmt.eprintf("=== %v incorrect frees - temp allocator: ===\n", len(track_temp.bad_free_array))
+				for entry in track_temp.bad_free_array {
+					fmt.eprintf("- %p @ %v\n", entry.memory, entry.location)
 				}
 				mem.tracking_allocator_destroy(&track_temp)
 			}
@@ -52,12 +43,15 @@ main :: proc() {
 			}
 			mem.tracking_allocator_destroy(&track)
 		}
+		// Logger
+		context.logger = log.create_console_logger()
+		defer log.destroy_console_logger(context.logger)
 	}
 
 	args := os.args
 	if len(args) < 2 {
 		fmt.eprintln("Usage: examples <example_name>")
-		fmt.eprintln("Available examples: hellope-shapes, hellope-text, hellope-clay, hellope-custom")
+		fmt.eprintln("Available examples: hellope-shapes, hellope-text, hellope-clay, hellope-custom, textures")
 		os.exit(1)
 	}
 
@@ -66,9 +60,10 @@ main :: proc() {
 	case "hellope-custom": hellope_custom()
 	case "hellope-shapes": hellope_shapes()
 	case "hellope-text": hellope_text()
+	case "textures": textures()
 	case:
 		fmt.eprintf("Unknown example: %v\n", args[1])
-		fmt.eprintln("Available examples: hellope-shapes, hellope-text, hellope-clay, hellope-custom")
+		fmt.eprintln("Available examples: hellope-shapes, hellope-text, hellope-clay, hellope-custom, textures")
 		os.exit(1)
 	}
 }

draw/examples/hellope.odin

@@ -78,10 +78,11 @@ hellope_shapes :: proc() {
 		draw.ellipse(base_layer, {410, 340}, 50, 30, {255, 200, 50, 255}, rotation = spin_angle)
 
 		// Circle orbiting a point (moon orbiting planet)
+		// Convention B: center = pivot point (planet), origin = offset from moon center to pivot.
+		// Moon's visual center at rotation=0: planet_pos - origin = (100, 450) - (0, 40) = (100, 410).
 		planet_pos := [2]f32{100, 450}
-		moon_pos := planet_pos + {0, -40}
 		draw.circle(base_layer, planet_pos, 8, {200, 200, 200, 255}) // planet (stationary)
-		draw.circle(base_layer, moon_pos, 5, {100, 150, 255, 255}, origin = {0, 40}, rotation = spin_angle) // moon orbiting
+		draw.circle(base_layer, planet_pos, 5, {100, 150, 255, 255}, origin = {0, 40}, rotation = spin_angle) // moon orbiting
 
 		// Ring arc rotating in place
 		draw.ring(base_layer, {250, 450}, 15, 30, 0, 270, {100, 100, 220, 255}, rotation = spin_angle)

draw/examples/textures.odin

@@ -0,0 +1,272 @@
+package examples
+
+import "../../draw"
+import "../../draw/draw_qr"
+import "core:os"
+import sdl "vendor:sdl3"
+
+textures :: proc() {
+	if !sdl.Init({.VIDEO}) do os.exit(1)
+	window := sdl.CreateWindow("Textures", 800, 600, {.HIGH_PIXEL_DENSITY})
+	gpu := sdl.CreateGPUDevice(draw.PLATFORM_SHADER_FORMAT, true, nil)
+	if !sdl.ClaimWindowForGPUDevice(gpu, window) do os.exit(1)
+	if !draw.init(gpu, window) do os.exit(1)
+	JETBRAINS_MONO_REGULAR = draw.register_font(JETBRAINS_MONO_REGULAR_RAW)
+
+	FONT_SIZE :: u16(14)
+	LABEL_OFFSET :: f32(8) // gap between item and its label
+
+	//----- Texture registration ----------------------------------
+
+	checker_size :: 8
+	checker_pixels: [checker_size * checker_size * 4]u8
+	for y in 0 ..< checker_size {
+		for x in 0 ..< checker_size {
+			i := (y * checker_size + x) * 4
+			is_dark := ((x + y) % 2) == 0
+			val: u8 = 40 if is_dark else 220
+			checker_pixels[i + 0] = val // R
+			checker_pixels[i + 1] = val / 2 // G — slight color tint
+			checker_pixels[i + 2] = val // B
+			checker_pixels[i + 3] = 255 // A
+		}
+	}
+	checker_texture, _ := draw.register_texture(
+		draw.Texture_Desc {
+			width = checker_size,
+			height = checker_size,
+			depth_or_layers = 1,
+			type = .D2,
+			format = .R8G8B8A8_UNORM,
+			usage = {.SAMPLER},
+			mip_levels = 1,
+		},
+		checker_pixels[:],
+	)
+	defer draw.unregister_texture(checker_texture)
+
+	stripe_w :: 16
+	stripe_h :: 8
+	stripe_pixels: [stripe_w * stripe_h * 4]u8
+	for y in 0 ..< stripe_h {
+		for x in 0 ..< stripe_w {
+			i := (y * stripe_w + x) * 4
+			stripe_pixels[i + 0] = u8(x * 255 / (stripe_w - 1)) // R gradient left→right
+			stripe_pixels[i + 1] = u8(y * 255 / (stripe_h - 1)) // G gradient top→bottom
+			stripe_pixels[i + 2] = 128 // B constant
+			stripe_pixels[i + 3] = 255 // A
+		}
+	}
+	stripe_texture, _ := draw.register_texture(
+		draw.Texture_Desc {
+			width = stripe_w,
+			height = stripe_h,
+			depth_or_layers = 1,
+			type = .D2,
+			format = .R8G8B8A8_UNORM,
+			usage = {.SAMPLER},
+			mip_levels = 1,
+		},
+		stripe_pixels[:],
+	)
+	defer draw.unregister_texture(stripe_texture)
+
+	qr_texture, _ := draw_qr.register_texture_from("https://x.com/miiilato/status/1880241066471051443")
+	defer draw.unregister_texture(qr_texture)
+
+	spin_angle: f32 = 0
+
+	//----- Draw loop ----------------------------------
+
+	for {
+		defer free_all(context.temp_allocator)
+		ev: sdl.Event
+		for sdl.PollEvent(&ev) {
+			if ev.type == .QUIT do return
+		}
+		spin_angle += 1
+
+		base_layer := draw.begin({width = 800, height = 600})
+
+		// Background
+		draw.rectangle(base_layer, {0, 0, 800, 600}, {30, 30, 30, 255})
+
+		//----- Row 1: Sampler presets (y=30) ----------------------------------
+
+		ROW1_Y :: f32(30)
+		ITEM_SIZE :: f32(120)
+		COL1 :: f32(30)
+		COL2 :: f32(180)
+		COL3 :: f32(330)
+		COL4 :: f32(480)
+
+		// Nearest (sharp pixel edges)
+		draw.rectangle_texture(
+			base_layer,
+			{COL1, ROW1_Y, ITEM_SIZE, ITEM_SIZE},
+			checker_texture,
+			sampler = .Nearest_Clamp,
+		)
+		draw.text(
+			base_layer,
+			"Nearest",
+			{COL1, ROW1_Y + ITEM_SIZE + LABEL_OFFSET},
+			JETBRAINS_MONO_REGULAR,
+			FONT_SIZE,
+			color = draw.WHITE,
+		)
+
+		// Linear (bilinear blur)
+		draw.rectangle_texture(
+			base_layer,
+			{COL2, ROW1_Y, ITEM_SIZE, ITEM_SIZE},
+			checker_texture,
+			sampler = .Linear_Clamp,
+		)
+		draw.text(
+			base_layer,
+			"Linear",
+			{COL2, ROW1_Y + ITEM_SIZE + LABEL_OFFSET},
+			JETBRAINS_MONO_REGULAR,
+			FONT_SIZE,
+			color = draw.WHITE,
+		)
+
+		// Tiled (4x repeat)
+		draw.rectangle_texture(
+			base_layer,
+			{COL3, ROW1_Y, ITEM_SIZE, ITEM_SIZE},
+			checker_texture,
+			sampler = .Nearest_Repeat,
+			uv_rect = {0, 0, 4, 4},
+		)
+		draw.text(
+			base_layer,
+			"Tiled 4x",
+			{COL3, ROW1_Y + ITEM_SIZE + LABEL_OFFSET},
+			JETBRAINS_MONO_REGULAR,
+			FONT_SIZE,
+			color = draw.WHITE,
+		)
+
+		//----- Row 2: Sampler presets (y=190) ----------------------------------
+
+		ROW2_Y :: f32(190)
+
+		// QR code (RGBA texture with baked colors, nearest sampling)
+		draw.rectangle(base_layer, {COL1, ROW2_Y, ITEM_SIZE, ITEM_SIZE}, {255, 255, 255, 255}) // white bg
+		draw.rectangle_texture(
+			base_layer,
+			{COL1, ROW2_Y, ITEM_SIZE, ITEM_SIZE},
+			qr_texture,
+			sampler = .Nearest_Clamp,
+		)
+		draw.text(
+			base_layer,
+			"QR Code",
+			{COL1, ROW2_Y + ITEM_SIZE + LABEL_OFFSET},
+			JETBRAINS_MONO_REGULAR,
+			FONT_SIZE,
+			color = draw.WHITE,
+		)
+
+		// Rounded corners
+		draw.rectangle_texture(
+			base_layer,
+			{COL2, ROW2_Y, ITEM_SIZE, ITEM_SIZE},
+			checker_texture,
+			sampler = .Nearest_Clamp,
+			roundness = 0.3,
+		)
+		draw.text(
+			base_layer,
+			"Rounded",
+			{COL2, ROW2_Y + ITEM_SIZE + LABEL_OFFSET},
+			JETBRAINS_MONO_REGULAR,
+			FONT_SIZE,
+			color = draw.WHITE,
+		)
+
+		// Rotating
+		rot_rect := draw.Rectangle{COL3, ROW2_Y, ITEM_SIZE, ITEM_SIZE}
+		draw.rectangle_texture(
+			base_layer,
+			rot_rect,
+			checker_texture,
+			sampler = .Nearest_Clamp,
+			origin = draw.center_of(rot_rect),
+			rotation = spin_angle,
+		)
+		draw.text(
+			base_layer,
+			"Rotating",
+			{COL3, ROW2_Y + ITEM_SIZE + LABEL_OFFSET},
+			JETBRAINS_MONO_REGULAR,
+			FONT_SIZE,
+			color = draw.WHITE,
+		)
+
+		//----- Row 3: Fit modes + Per-corner radii (y=360) ----------------------------------
+
+		ROW3_Y :: f32(360)
+		FIT_SIZE :: f32(120) // square target rect
+
+		// Stretch
+		uv_s, sampler_s, inner_s := draw.fit_params(.Stretch, {COL1, ROW3_Y, FIT_SIZE, FIT_SIZE}, stripe_texture)
+		draw.rectangle(base_layer, {COL1, ROW3_Y, FIT_SIZE, FIT_SIZE}, {60, 60, 60, 255}) // bg
+		draw.rectangle_texture(base_layer, inner_s, stripe_texture, uv_rect = uv_s, sampler = sampler_s)
+		draw.text(
+			base_layer,
+			"Stretch",
+			{COL1, ROW3_Y + FIT_SIZE + LABEL_OFFSET},
+			JETBRAINS_MONO_REGULAR,
+			FONT_SIZE,
+			color = draw.WHITE,
+		)
+
+		// Fill (center-crop)
+		uv_f, sampler_f, inner_f := draw.fit_params(.Fill, {COL2, ROW3_Y, FIT_SIZE, FIT_SIZE}, stripe_texture)
+		draw.rectangle(base_layer, {COL2, ROW3_Y, FIT_SIZE, FIT_SIZE}, {60, 60, 60, 255})
+		draw.rectangle_texture(base_layer, inner_f, stripe_texture, uv_rect = uv_f, sampler = sampler_f)
+		draw.text(
+			base_layer,
+			"Fill",
+			{COL2, ROW3_Y + FIT_SIZE + LABEL_OFFSET},
+			JETBRAINS_MONO_REGULAR,
+			FONT_SIZE,
+			color = draw.WHITE,
+		)
+
+		// Fit (letterbox)
+		uv_ft, sampler_ft, inner_ft := draw.fit_params(.Fit, {COL3, ROW3_Y, FIT_SIZE, FIT_SIZE}, stripe_texture)
+		draw.rectangle(base_layer, {COL3, ROW3_Y, FIT_SIZE, FIT_SIZE}, {60, 60, 60, 255}) // visible margin bg
+		draw.rectangle_texture(base_layer, inner_ft, stripe_texture, uv_rect = uv_ft, sampler = sampler_ft)
+		draw.text(
+			base_layer,
+			"Fit",
+			{COL3, ROW3_Y + FIT_SIZE + LABEL_OFFSET},
+			JETBRAINS_MONO_REGULAR,
+			FONT_SIZE,
+			color = draw.WHITE,
+		)
+
+		// Per-corner radii
+		draw.rectangle_texture_corners(
+			base_layer,
+			{COL4, ROW3_Y, FIT_SIZE, FIT_SIZE},
+			{20, 0, 20, 0},
+			checker_texture,
+			sampler = .Nearest_Clamp,
+		)
+		draw.text(
+			base_layer,
+			"Per-corner",
+			{COL4, ROW3_Y + FIT_SIZE + LABEL_OFFSET},
+			JETBRAINS_MONO_REGULAR,
+			FONT_SIZE,
+			color = draw.WHITE,
+		)
+
+		draw.end(gpu, window)
+	}
+}

draw/pipeline_2d_base.odin

@@ -35,6 +35,7 @@ Shape_Kind :: enum u8 {
 
 Shape_Flag :: enum u8 {
 	Stroke,
+	Textured,
 }
 
 Shape_Flags :: bit_set[Shape_Flag;u8]
@@ -106,9 +107,10 @@ Primitive :: struct {
 	rotation:   f32, // 24: shader self-rotation in radians (used by RRect, Ellipse)
 	_pad:       f32, // 28: alignment to vec4 boundary
 	params:     Shape_Params, // 32: two vec4s of shape params
+	uv_rect:    [4]f32, // 64: u_min, v_min, u_max, v_max (default {0,0,1,1})
 }
 
-#assert(size_of(Primitive) == 64)
+#assert(size_of(Primitive) == 80)
 
 pack_kind_flags :: #force_inline proc(kind: Shape_Kind, flags: Shape_Flags) -> u32 {
 	return u32(kind) | (u32(transmute(u8)flags) << 8)
@@ -566,6 +568,7 @@ draw_layer :: proc(
 	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))
@@ -584,14 +587,24 @@ draw_layer :: proc(
 					sdl.BindGPUVertexBuffers(render_pass, 0, &sdl.GPUBufferBinding{buffer = main_vert_buf, offset = 0}, 1)
 					current_vert_buf = main_vert_buf
 				}
-				if current_atlas != white_texture {
+				// 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 = white_texture, sampler = sampler},
+						&sdl.GPUTextureSamplerBinding{texture = batch_texture, sampler = batch_sampler},
 						1,
 					)
-					current_atlas = white_texture
+					current_atlas = batch_texture
+					current_sampler = batch_sampler
 				}
 				sdl.DrawGPUPrimitives(render_pass, batch.count, 1, batch.offset, 0)
 
@@ -632,14 +645,24 @@ draw_layer :: proc(
 					sdl.BindGPUVertexBuffers(render_pass, 0, &sdl.GPUBufferBinding{buffer = unit_quad, offset = 0}, 1)
 					current_vert_buf = unit_quad
 				}
-				if current_atlas != white_texture {
+				// 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 = white_texture, sampler = sampler},
+						&sdl.GPUTextureSamplerBinding{texture = batch_texture, sampler = batch_sampler},
 						1,
 					)
-					current_atlas = white_texture
+					current_atlas = batch_texture
+					current_sampler = batch_sampler
 				}
 				sdl.DrawGPUPrimitives(render_pass, 6, batch.count, 0, batch.offset)
 			}

draw/shaders/generated/base_2d.frag.metal

@@ -25,6 +25,7 @@ struct main0_in
     float4 f_params2 [[user(locn3)]];
     uint f_kind_flags [[user(locn4)]];
     float f_rotation [[user(locn5), flat]];
+    float4 f_uv_rect [[user(locn6), flat]];
 };
 
 static inline __attribute__((always_inline))
@@ -69,6 +70,12 @@ float sdf_stroke(thread const float& d, thread const float& stroke_width)
     return abs(d) - (stroke_width * 0.5);
 }
 
+static inline __attribute__((always_inline))
+float sdf_alpha(thread const float& d, thread const float& soft)
+{
+    return 1.0 - smoothstep(-soft, soft, d);
+}
+
 static inline __attribute__((always_inline))
 float sdCircle(thread const float2& p, thread const float& r)
 {
@@ -127,12 +134,6 @@ float sdSegment(thread const float2& p, thread const float2& a, thread const flo
     return length(pa - (ba * h));
 }
 
-static inline __attribute__((always_inline))
-float sdf_alpha(thread const float& d, thread const float& soft)
-{
-    return 1.0 - smoothstep(-soft, soft, d);
-}
-
 fragment main0_out main0(main0_in in [[stage_in]], texture2d<float> tex [[texture(0)]], sampler texSmplr [[sampler(0)]])
 {
     main0_out out = {};
@@ -169,6 +170,25 @@ fragment main0_out main0(main0_in in [[stage_in]], texture2d<float> tex [[textur
             float param_6 = stroke_px;
             d = sdf_stroke(param_5, param_6);
         }
+        float4 shape_color = in.f_color;
+        if ((flags & 2u) != 0u)
+        {
+            float2 p_for_uv = in.f_local_or_uv;
+            if (in.f_rotation != 0.0)
+            {
+                float2 param_7 = p_for_uv;
+                float param_8 = in.f_rotation;
+                p_for_uv = apply_rotation(param_7, param_8);
+            }
+            float2 local_uv = ((p_for_uv / b) * 0.5) + float2(0.5);
+            float2 uv = mix(in.f_uv_rect.xy, in.f_uv_rect.zw, local_uv);
+            shape_color *= tex.sample(texSmplr, uv);
+        }
+        float param_9 = d;
+        float param_10 = soft;
+        float alpha = sdf_alpha(param_9, param_10);
+        out.out_color = float4(shape_color.xyz, shape_color.w * alpha);
+        return out;
     }
     else
     {
@@ -177,14 +197,14 @@ fragment main0_out main0(main0_in in [[stage_in]], texture2d<float> tex [[textur
             float radius = in.f_params.x;
             soft = fast::max(in.f_params.y, 1.0);
             float stroke_px_1 = in.f_params.z;
-            float2 param_7 = in.f_local_or_uv;
-            float param_8 = radius;
-            d = sdCircle(param_7, param_8);
+            float2 param_11 = in.f_local_or_uv;
+            float param_12 = radius;
+            d = sdCircle(param_11, param_12);
             if ((flags & 1u) != 0u)
             {
-                float param_9 = d;
-                float param_10 = stroke_px_1;
-                d = sdf_stroke(param_9, param_10);
+                float param_13 = d;
+                float param_14 = stroke_px_1;
+                d = sdf_stroke(param_13, param_14);
             }
         }
         else
@@ -197,19 +217,19 @@ fragment main0_out main0(main0_in in [[stage_in]], texture2d<float> tex [[textur
                 float2 p_local_1 = in.f_local_or_uv;
                 if (in.f_rotation != 0.0)
                 {
-                    float2 param_11 = p_local_1;
-                    float param_12 = in.f_rotation;
-                    p_local_1 = apply_rotation(param_11, param_12);
+                    float2 param_15 = p_local_1;
+                    float param_16 = in.f_rotation;
+                    p_local_1 = apply_rotation(param_15, param_16);
                 }
-                float2 param_13 = p_local_1;
-                float2 param_14 = ab;
-                float _560 = sdEllipse(param_13, param_14);
-                d = _560;
+                float2 param_17 = p_local_1;
+                float2 param_18 = ab;
+                float _616 = sdEllipse(param_17, param_18);
+                d = _616;
                 if ((flags & 1u) != 0u)
                 {
-                    float param_15 = d;
-                    float param_16 = stroke_px_2;
-                    d = sdf_stroke(param_15, param_16);
+                    float param_19 = d;
+                    float param_20 = stroke_px_2;
+                    d = sdf_stroke(param_19, param_20);
                 }
             }
             else
@@ -220,10 +240,10 @@ fragment main0_out main0(main0_in in [[stage_in]], texture2d<float> tex [[textur
                     float2 b_1 = in.f_params.zw;
                     float width = in.f_params2.x;
                     soft = fast::max(in.f_params2.y, 1.0);
-                    float2 param_17 = in.f_local_or_uv;
-                    float2 param_18 = a;
-                    float2 param_19 = b_1;
-                    d = sdSegment(param_17, param_18, param_19) - (width * 0.5);
+                    float2 param_21 = in.f_local_or_uv;
+                    float2 param_22 = a;
+                    float2 param_23 = b_1;
+                    d = sdSegment(param_21, param_22, param_23) - (width * 0.5);
                 }
                 else
                 {
@@ -243,16 +263,16 @@ fragment main0_out main0(main0_in in [[stage_in]], texture2d<float> tex [[textur
                         }
                         float ang_start = mod(start_rad, 6.283185482025146484375);
                         float ang_end = mod(end_rad, 6.283185482025146484375);
-                        float _654;
+                        float _710;
                         if (ang_end > ang_start)
                         {
-                            _654 = float((angle >= ang_start) && (angle <= ang_end));
+                            _710 = float((angle >= ang_start) && (angle <= ang_end));
                         }
                         else
                         {
-                            _654 = float((angle >= ang_start) || (angle <= ang_end));
+                            _710 = float((angle >= ang_start) || (angle <= ang_end));
                         }
-                        float in_arc = _654;
+                        float in_arc = _710;
                         if (abs(ang_end - ang_start) >= 6.282185077667236328125)
                         {
                             in_arc = 1.0;
@@ -277,9 +297,9 @@ fragment main0_out main0(main0_in in [[stage_in]], texture2d<float> tex [[textur
                             d = (length(p) * cos(bn)) - radius_1;
                             if ((flags & 1u) != 0u)
                             {
-                                float param_20 = d;
-                                float param_21 = stroke_px_3;
-                                d = sdf_stroke(param_20, param_21);
+                                float param_24 = d;
+                                float param_25 = stroke_px_3;
+                                d = sdf_stroke(param_24, param_25);
                             }
                         }
                     }
@@ -287,10 +307,9 @@ fragment main0_out main0(main0_in in [[stage_in]], texture2d<float> tex [[textur
             }
         }
     }
-    float param_22 = d;
-    float param_23 = soft;
-    float alpha = sdf_alpha(param_22, param_23);
-    out.out_color = float4(in.f_color.xyz, in.f_color.w * alpha);
+    float param_26 = d;
+    float param_27 = soft;
+    float alpha_1 = sdf_alpha(param_26, param_27);
+    out.out_color = float4(in.f_color.xyz, in.f_color.w * alpha_1);
     return out;
 }
-

draw/shaders/generated/base_2d.vert.metal

@@ -19,6 +19,7 @@ struct Primitive
     float _pad;
     float4 params;
     float4 params2;
+    float4 uv_rect;
 };
 
 struct Primitive_1
@@ -30,6 +31,7 @@ struct Primitive_1
     float _pad;
     float4 params;
     float4 params2;
+    float4 uv_rect;
 };
 
 struct Primitives
@@ -45,6 +47,7 @@ struct main0_out
     float4 f_params2 [[user(locn3)]];
     uint f_kind_flags [[user(locn4)]];
     float f_rotation [[user(locn5)]];
+    float4 f_uv_rect [[user(locn6)]];
     float4 gl_Position [[position]];
 };
 
@@ -55,7 +58,7 @@ struct main0_in
     float4 v_color [[attribute(2)]];
 };
 
-vertex main0_out main0(main0_in in [[stage_in]], constant Uniforms& _12 [[buffer(0)]], const device Primitives& _72 [[buffer(1)]], uint gl_InstanceIndex [[instance_id]])
+vertex main0_out main0(main0_in in [[stage_in]], constant Uniforms& _12 [[buffer(0)]], const device Primitives& _74 [[buffer(1)]], uint gl_InstanceIndex [[instance_id]])
 {
     main0_out out = {};
     if (_12.mode == 0u)
@@ -66,18 +69,20 @@ vertex main0_out main0(main0_in in [[stage_in]], constant Uniforms& _12 [[buffer
         out.f_params2 = float4(0.0);
         out.f_kind_flags = 0u;
         out.f_rotation = 0.0;
+        out.f_uv_rect = float4(0.0, 0.0, 1.0, 1.0);
         out.gl_Position = _12.projection * float4(in.v_position * _12.dpi_scale, 0.0, 1.0);
     }
     else
     {
         Primitive p;
-        p.bounds = _72.primitives[int(gl_InstanceIndex)].bounds;
-        p.color = _72.primitives[int(gl_InstanceIndex)].color;
-        p.kind_flags = _72.primitives[int(gl_InstanceIndex)].kind_flags;
-        p.rotation = _72.primitives[int(gl_InstanceIndex)].rotation;
-        p._pad = _72.primitives[int(gl_InstanceIndex)]._pad;
-        p.params = _72.primitives[int(gl_InstanceIndex)].params;
-        p.params2 = _72.primitives[int(gl_InstanceIndex)].params2;
+        p.bounds = _74.primitives[int(gl_InstanceIndex)].bounds;
+        p.color = _74.primitives[int(gl_InstanceIndex)].color;
+        p.kind_flags = _74.primitives[int(gl_InstanceIndex)].kind_flags;
+        p.rotation = _74.primitives[int(gl_InstanceIndex)].rotation;
+        p._pad = _74.primitives[int(gl_InstanceIndex)]._pad;
+        p.params = _74.primitives[int(gl_InstanceIndex)].params;
+        p.params2 = _74.primitives[int(gl_InstanceIndex)].params2;
+        p.uv_rect = _74.primitives[int(gl_InstanceIndex)].uv_rect;
         float2 corner = in.v_position;
         float2 world_pos = mix(p.bounds.xy, p.bounds.zw, corner);
         float2 center = (p.bounds.xy + p.bounds.zw) * 0.5;
@@ -87,8 +92,8 @@ vertex main0_out main0(main0_in in [[stage_in]], constant Uniforms& _12 [[buffer
         out.f_params2 = p.params2;
         out.f_kind_flags = p.kind_flags;
         out.f_rotation = p.rotation;
+        out.f_uv_rect = p.uv_rect;
         out.gl_Position = _12.projection * float4(world_pos * _12.dpi_scale, 0.0, 1.0);
     }
     return out;
 }
-

draw/shaders/source/base_2d.frag

@@ -7,6 +7,7 @@ layout(location = 2) in vec4 f_params;
 layout(location = 3) in vec4 f_params2;
 layout(location = 4) flat in uint f_kind_flags;
 layout(location = 5) flat in float f_rotation;
+layout(location = 6) flat in vec4 f_uv_rect;
 
 // --- Output ---
 layout(location = 0) out vec4 out_color;
@@ -130,6 +131,23 @@ void main() {
 
         d = sdRoundedBox(p_local, b, r);
         if ((flags & 1u) != 0u) d = sdf_stroke(d, stroke_px);
+
+        // Texture sampling for textured SDF primitives
+        vec4 shape_color = f_color;
+        if ((flags & 2u) != 0u) {
+            // Compute UV from local position and half_size
+            vec2 p_for_uv = f_local_or_uv;
+            if (f_rotation != 0.0) {
+                p_for_uv = apply_rotation(p_for_uv, f_rotation);
+            }
+            vec2 local_uv = p_for_uv / b * 0.5 + 0.5;
+            vec2 uv = mix(f_uv_rect.xy, f_uv_rect.zw, local_uv);
+            shape_color *= texture(tex, uv);
+        }
+
+        float alpha = sdf_alpha(d, soft);
+        out_color = vec4(shape_color.rgb, shape_color.a * alpha);
+        return;
     }
     else if (kind == 2u) {
         // Circle — rotationally symmetric, no rotation needed

draw/shaders/source/base_2d.vert

@@ -12,6 +12,7 @@ layout(location = 2) out vec4 f_params;
 layout(location = 3) out vec4 f_params2;
 layout(location = 4) flat out uint f_kind_flags;
 layout(location = 5) flat out float f_rotation;
+layout(location = 6) flat out vec4 f_uv_rect;
 
 // ---------- Uniforms (single block — avoids spirv-cross reordering on Metal) ----------
 layout(set = 1, binding = 0) uniform Uniforms {
@@ -29,6 +30,7 @@ struct Primitive {
     float _pad; // 28-31: alignment padding
     vec4 params; // 32-47: shape params part 1
     vec4 params2; // 48-63: shape params part 2
+    vec4 uv_rect; // 64-79: u_min, v_min, u_max, v_max
 };
 
 layout(std430, set = 0, binding = 0) readonly buffer Primitives {
@@ -45,6 +47,7 @@ void main() {
         f_params2 = vec4(0.0);
         f_kind_flags = 0u;
         f_rotation = 0.0;
+        f_uv_rect = vec4(0.0, 0.0, 1.0, 1.0);
 
         gl_Position = projection * vec4(v_position * dpi_scale, 0.0, 1.0);
     } else {
@@ -61,6 +64,7 @@ void main() {
         f_params2 = p.params2;
         f_kind_flags = p.kind_flags;
         f_rotation = p.rotation;
+        f_uv_rect = p.uv_rect;
 
         gl_Position = projection * vec4(world_pos * dpi_scale, 0.0, 1.0);
     }

draw/shapes.odin

@@ -68,6 +68,19 @@ emit_rectangle :: proc(x, y, width, height: f32, color: Color, vertices: []Verte
 	vertices[offset + 5] = solid_vertex({x, y + height}, color)
 }
 
+@(private = "file")
+prepare_sdf_primitive_textured :: proc(
+	layer: ^Layer,
+	prim: Primitive,
+	texture_id: Texture_Id,
+	sampler: Sampler_Preset,
+) {
+	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)
+}
+
 // ----- Drawing functions ----
 
 pixel :: proc(layer: ^Layer, pos: [2]f32, color: Color) {
@@ -83,6 +96,7 @@ rectangle_gradient :: proc(
 	temp_allocator := context.temp_allocator,
 ) {
 	vertices := make([]Vertex, 6, temp_allocator)
+	defer delete(vertices, temp_allocator)
 
 	corner_top_left := [2]f32{rect.x, rect.y}
 	corner_top_right := [2]f32{rect.x + rect.width, rect.y}
@@ -115,6 +129,7 @@ circle_sector :: proc(
 
 	vertex_count := segment_count * 3
 	vertices := make([]Vertex, vertex_count, temp_allocator)
+	defer delete(vertices, temp_allocator)
 
 	start_radians := math.to_radians(start_angle)
 	end_radians := math.to_radians(end_angle)
@@ -167,6 +182,7 @@ circle_gradient :: proc(
 
 	vertex_count := segment_count * 3
 	vertices := make([]Vertex, vertex_count, temp_allocator)
+	defer delete(vertices, temp_allocator)
 
 	step_angle := math.TAU / f32(segment_count)
 
@@ -238,6 +254,7 @@ triangle_lines :: proc(
 	temp_allocator := context.temp_allocator,
 ) {
 	vertices := make([]Vertex, 18, temp_allocator)
+	defer delete(vertices, temp_allocator)
 	write_offset := 0
 
 	if !needs_transform(origin, rotation) {
@@ -273,6 +290,7 @@ triangle_fan :: proc(
 	triangle_count := len(points) - 2
 	vertex_count := triangle_count * 3
 	vertices := make([]Vertex, vertex_count, temp_allocator)
+	defer delete(vertices, temp_allocator)
 
 	if !needs_transform(origin, rotation) {
 		for i in 1 ..< len(points) - 1 {
@@ -312,6 +330,7 @@ triangle_strip :: proc(
 	triangle_count := len(points) - 2
 	vertex_count := triangle_count * 3
 	vertices := make([]Vertex, vertex_count, temp_allocator)
+	defer delete(vertices, temp_allocator)
 
 	if !needs_transform(origin, rotation) {
 		for i in 0 ..< triangle_count {
@@ -352,17 +371,20 @@ triangle_strip :: proc(
 
 // ----- SDF drawing functions ----
 
-// Compute new center position after rotating a center-parametrized shape
-// around a pivot point. The pivot is at (center + origin) in world space.
+// 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).
 @(private = "file")
 compute_pivot_center :: proc(center: [2]f32, origin: [2]f32, rotation_deg: f32) -> [2]f32 {
 	if origin == {0, 0} do return center
 	theta := math.to_radians(rotation_deg)
 	cos_angle, sin_angle := math.cos(theta), math.sin(theta)
-	// pivot = center + origin; new_center = pivot + R(θ) * (center - pivot)
 	return(
 		center +
-		origin +
 		{cos_angle * (-origin.x) - sin_angle * (-origin.y), sin_angle * (-origin.x) + cos_angle * (-origin.y)} \
 	)
 }
@@ -378,6 +400,13 @@ rotated_aabb_half_extents :: proc(half_width, half_height, rotation_radians: f32
 // Draw a filled rectangle via SDF (analytical anti-aliasing at all orientations).
 // `roundness` is a 0–1 fraction controlling uniform corner rounding — 0 is sharp, 1 is fully rounded.
 // For per-corner pixel-precise rounding, use `rectangle_corners` instead.
+//
+// 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.
+//   When `origin = center_of_rectangle(rect)`, `rect.x, rect.y` is the visual center.
+//   Rotation always occurs around the anchor point.
 rectangle :: proc(
 	layer: ^Layer,
 	rect: Rectangle,
@@ -394,6 +423,7 @@ rectangle :: proc(
 // Draw a stroked rectangle via SDF (analytical anti-aliasing at all orientations).
 // `roundness` is a 0–1 fraction controlling uniform corner rounding — 0 is sharp, 1 is fully rounded.
 // For per-corner pixel-precise rounding, use `rectangle_corners_lines` instead.
+// Origin semantics: see `rectangle`.
 rectangle_lines :: proc(
 	layer: ^Layer,
 	rect: Rectangle,
@@ -409,6 +439,7 @@ rectangle_lines :: proc(
 }
 
 // Draw a rectangle with per-corner rounding radii via SDF.
+// Origin semantics: see `rectangle`.
 rectangle_corners :: proc(
 	layer: ^Layer,
 	rect: Rectangle,
@@ -430,12 +461,12 @@ rectangle_corners :: proc(
 	half_width := rect.width * 0.5
 	half_height := rect.height * 0.5
 	rotation_radians: f32 = 0
-	center_x := rect.x + half_width
-	center_y := rect.y + half_height
+	center_x := rect.x + half_width - origin.x
+	center_y := rect.y + half_height - origin.y
 
 	if needs_transform(origin, rotation) {
 		rotation_radians = math.to_radians(rotation)
-		transform := build_pivot_rotation({rect.x, rect.y}, origin, rotation)
+		transform := build_pivot_rotation({rect.x + origin.x, rect.y + origin.y}, origin, rotation)
 		new_center := apply_transform(transform, {half_width, half_height})
 		center_x = new_center.x
 		center_y = new_center.y
@@ -474,6 +505,7 @@ rectangle_corners :: proc(
 }
 
 // Draw a stroked rectangle with per-corner rounding radii via SDF.
+// Origin semantics: see `rectangle`.
 rectangle_corners_lines :: proc(
 	layer: ^Layer,
 	rect: Rectangle,
@@ -496,12 +528,12 @@ rectangle_corners_lines :: proc(
 	half_width := rect.width * 0.5
 	half_height := rect.height * 0.5
 	rotation_radians: f32 = 0
-	center_x := rect.x + half_width
-	center_y := rect.y + half_height
+	center_x := rect.x + half_width - origin.x
+	center_y := rect.y + half_height - origin.y
 
 	if needs_transform(origin, rotation) {
 		rotation_radians = math.to_radians(rotation)
-		transform := build_pivot_rotation({rect.x, rect.y}, origin, rotation)
+		transform := build_pivot_rotation({rect.x + origin.x, rect.y + origin.y}, origin, rotation)
 		new_center := apply_transform(transform, {half_width, half_height})
 		center_x = new_center.x
 		center_y = new_center.y
@@ -539,7 +571,114 @@ rectangle_corners_lines :: proc(
 	prepare_sdf_primitive(layer, prim)
 }
 
+// Draw a rectangle with a texture fill via SDF. Supports rounded corners via `roundness`,
+// rotation, and analytical anti-aliasing on the shape silhouette.
+// Origin semantics: see `rectangle`.
+rectangle_texture :: proc(
+	layer: ^Layer,
+	rect: Rectangle,
+	id: Texture_Id,
+	tint: Color = WHITE,
+	uv_rect: Rectangle = {0, 0, 1, 1},
+	sampler: Sampler_Preset = .Linear_Clamp,
+	roundness: f32 = 0,
+	origin: [2]f32 = {0, 0},
+	rotation: f32 = 0,
+	soft_px: f32 = 1.0,
+) {
+	cr := min(rect.width, rect.height) * clamp(roundness, 0, 1) * 0.5
+	rectangle_texture_corners(
+		layer,
+		rect,
+		{cr, cr, cr, cr},
+		id,
+		tint,
+		uv_rect,
+		sampler,
+		origin,
+		rotation,
+		soft_px,
+	)
+}
+
+// Draw a rectangle with a texture fill and per-corner rounding radii via SDF.
+// Origin semantics: see `rectangle`.
+rectangle_texture_corners :: proc(
+	layer: ^Layer,
+	rect: Rectangle,
+	radii: [4]f32,
+	id: Texture_Id,
+	tint: Color = WHITE,
+	uv_rect: Rectangle = {0, 0, 1, 1},
+	sampler: Sampler_Preset = .Linear_Clamp,
+	origin: [2]f32 = {0, 0},
+	rotation: f32 = 0,
+	soft_px: f32 = 1.0,
+) {
+	max_radius := min(rect.width, rect.height) * 0.5
+	top_left := clamp(radii[0], 0, max_radius)
+	top_right := clamp(radii[1], 0, max_radius)
+	bottom_right := clamp(radii[2], 0, max_radius)
+	bottom_left := clamp(radii[3], 0, max_radius)
+
+	padding := soft_px / GLOB.dpi_scaling
+	dpi_scale := GLOB.dpi_scaling
+
+	half_width := rect.width * 0.5
+	half_height := rect.height * 0.5
+	rotation_radians: f32 = 0
+	center_x := rect.x + half_width - origin.x
+	center_y := rect.y + half_height - origin.y
+
+	if needs_transform(origin, rotation) {
+		rotation_radians = math.to_radians(rotation)
+		transform := build_pivot_rotation({rect.x + origin.x, rect.y + origin.y}, origin, rotation)
+		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 rotation_radians != 0 {
+		expanded := rotated_aabb_half_extents(half_width, half_height, rotation_radians)
+		bounds_half_width = expanded.x
+		bounds_half_height = expanded.y
+	}
+
+	prim := 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,
+		},
+		color      = tint,
+		kind_flags = pack_kind_flags(.RRect, {.Textured}),
+		rotation   = rotation_radians,
+		uv_rect    = {uv_rect.x, uv_rect.y, uv_rect.width, uv_rect.height},
+	}
+	prim.params.rrect = RRect_Params {
+		half_size = {half_width * dpi_scale, half_height * dpi_scale},
+		radii     = {
+			top_right * dpi_scale,
+			bottom_right * dpi_scale,
+			top_left * dpi_scale,
+			bottom_left * dpi_scale,
+		},
+		soft_px   = soft_px,
+		stroke_px = 0,
+	}
+	prepare_sdf_primitive_textured(layer, prim, id, sampler)
+}
+
 // Draw a filled circle via SDF.
+//
+// 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: [2]f32,
@@ -576,6 +715,7 @@ circle :: proc(
 }
 
 // Draw a stroked circle via SDF.
+// Origin semantics: see `circle`.
 circle_lines :: proc(
 	layer: ^Layer,
 	center: [2]f32,
@@ -613,6 +753,7 @@ circle_lines :: proc(
 }
 
 // Draw a filled ellipse via SDF.
+// Origin semantics: see `circle`.
 ellipse :: proc(
 	layer: ^Layer,
 	center: [2]f32,
@@ -659,6 +800,7 @@ ellipse :: proc(
 }
 
 // Draw a stroked ellipse via SDF.
+// Origin semantics: see `circle`.
 ellipse_lines :: proc(
 	layer: ^Layer,
 	center: [2]f32,
@@ -709,6 +851,7 @@ ellipse_lines :: proc(
 }
 
 // Draw a filled ring arc via SDF.
+// Origin semantics: see `circle`.
 ring :: proc(
 	layer: ^Layer,
 	center: [2]f32,
@@ -751,6 +894,7 @@ ring :: proc(
 }
 
 // Draw stroked ring arc outlines via SDF.
+// Origin semantics: see `circle`.
 ring_lines :: proc(
 	layer: ^Layer,
 	center: [2]f32,

draw/text.odin

@@ -139,6 +139,7 @@ text :: proc(
 	temp_allocator := context.temp_allocator,
 ) {
 	c_str := strings.clone_to_cstring(text_string, temp_allocator)
+	defer delete(c_str, temp_allocator)
 
 	sdl_text: ^sdl_ttf.Text
 	cached := false
@@ -180,6 +181,7 @@ measure_text :: proc(
 	allocator := context.temp_allocator,
 ) -> [2]f32 {
 	c_str := strings.clone_to_cstring(text_string, allocator)
+	defer delete(c_str, allocator)
 	width, height: c.int
 	if !sdl_ttf.GetStringSize(get_font(font_id, font_size), c_str, 0, &width, &height) {
 		log.panicf("Failed to measure text: %s", sdl.GetError())
@@ -244,7 +246,7 @@ bottom_right_of_text :: proc(text_string: string, font_id: Font_Id, font_size: u
 // After calling this, subsequent text draws with an `id` will re-create their cache entries.
 clear_text_cache :: proc() {
 	for _, sdl_text in GLOB.text_cache.cache {
-		sdl_ttf.DestroyText(sdl_text)
+		append(&GLOB.pending_text_releases, sdl_text)
 	}
 	clear(&GLOB.text_cache.cache)
 }
@@ -257,7 +259,7 @@ clear_text_cache_entry :: proc(id: u32) {
 	key := Cache_Key{id, .Custom}
 	sdl_text, ok := GLOB.text_cache.cache[key]
 	if ok {
-		sdl_ttf.DestroyText(sdl_text)
+		append(&GLOB.pending_text_releases, sdl_text)
 		delete_key(&GLOB.text_cache.cache, key)
 	}
 }

draw/textures.odin

@@ -0,0 +1,414 @@
+package draw
+
+import "core:log"
+import "core:mem"
+import sdl "vendor:sdl3"
+
+Texture_Id :: distinct u32
+INVALID_TEXTURE :: Texture_Id(0) // Slot 0 is reserved/unused
+
+Texture_Kind :: enum u8 {
+	Static, // Uploaded once, never changes (QR codes, decoded PNGs, icons)
+	Dynamic, // Updatable via update_texture_region
+	Stream, // Frequent full re-uploads (video, procedural)
+}
+
+Sampler_Preset :: enum u8 {
+	Nearest_Clamp,
+	Linear_Clamp,
+	Nearest_Repeat,
+	Linear_Repeat,
+}
+
+SAMPLER_PRESET_COUNT :: 4
+
+Fit_Mode :: enum u8 {
+	Stretch, // Fill rect, may distort aspect ratio (default)
+	Fit, // Preserve aspect, letterbox (may leave margins)
+	Fill, // Preserve aspect, center-crop (may crop edges)
+	Tile, // Repeat at native texture size
+	Center, // 1:1 pixel size, centered, no scaling
+}
+
+Texture_Desc :: struct {
+	width:           u32,
+	height:          u32,
+	depth_or_layers: u32,
+	type:            sdl.GPUTextureType,
+	format:          sdl.GPUTextureFormat,
+	usage:           sdl.GPUTextureUsageFlags,
+	mip_levels:      u32,
+	kind:            Texture_Kind,
+}
+
+// Internal slot — not exported.
+@(private)
+Texture_Slot :: struct {
+	gpu_texture: ^sdl.GPUTexture,
+	desc:        Texture_Desc,
+	generation:  u32,
+}
+
+// State stored in GLOB
+// This file references:
+//   GLOB.device                 : ^sdl.GPUDevice
+//   GLOB.texture_slots          : [dynamic]Texture_Slot
+//   GLOB.texture_free_list      : [dynamic]u32
+//   GLOB.pending_texture_releases : [dynamic]Texture_Id
+//   GLOB.samplers               : [SAMPLER_PRESET_COUNT]^sdl.GPUSampler
+
+Clay_Image_Data :: struct {
+	texture_id: Texture_Id,
+	fit:        Fit_Mode,
+	tint:       Color,
+}
+
+clay_image_data :: proc(id: Texture_Id, fit: Fit_Mode = .Stretch, tint: Color = WHITE) -> Clay_Image_Data {
+	return {texture_id = id, fit = fit, tint = tint}
+}
+
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Registration -------------
+// ---------------------------------------------------------------------------------------------------------------------
+
+// Register a texture. Draw owns the GPU resource and releases it on unregister.
+// `data` is tightly-packed row-major bytes matching desc.format.
+// The caller may free `data` immediately after this proc returns.
+@(require_results)
+register_texture :: proc(desc: Texture_Desc, data: []u8) -> (id: Texture_Id, ok: bool) {
+	device := GLOB.device
+	if device == nil {
+		log.error("register_texture called before draw.init()")
+		return INVALID_TEXTURE, false
+	}
+
+	assert(desc.width > 0, "Texture_Desc.width must be > 0")
+	assert(desc.height > 0, "Texture_Desc.height must be > 0")
+	assert(desc.depth_or_layers > 0, "Texture_Desc.depth_or_layers must be > 0")
+	assert(desc.mip_levels > 0, "Texture_Desc.mip_levels must be > 0")
+	assert(desc.usage != {}, "Texture_Desc.usage must not be empty (e.g. {.SAMPLER})")
+
+	// Create the GPU texture
+	gpu_texture := sdl.CreateGPUTexture(
+		device,
+		sdl.GPUTextureCreateInfo {
+			type = desc.type,
+			format = desc.format,
+			usage = desc.usage,
+			width = desc.width,
+			height = desc.height,
+			layer_count_or_depth = desc.depth_or_layers,
+			num_levels = desc.mip_levels,
+			sample_count = ._1,
+		},
+	)
+	if gpu_texture == nil {
+		log.errorf("Failed to create GPU texture (%dx%d): %s", desc.width, desc.height, sdl.GetError())
+		return INVALID_TEXTURE, false
+	}
+
+	// Upload pixel data via a transfer buffer
+	if len(data) > 0 {
+		data_size := u32(len(data))
+		transfer := sdl.CreateGPUTransferBuffer(
+			device,
+			sdl.GPUTransferBufferCreateInfo{usage = .UPLOAD, size = data_size},
+		)
+		if transfer == nil {
+			log.errorf("Failed to create texture transfer buffer: %s", sdl.GetError())
+			sdl.ReleaseGPUTexture(device, gpu_texture)
+			return INVALID_TEXTURE, false
+		}
+		defer sdl.ReleaseGPUTransferBuffer(device, transfer)
+
+		mapped := sdl.MapGPUTransferBuffer(device, transfer, false)
+		if mapped == nil {
+			log.errorf("Failed to map texture transfer buffer: %s", sdl.GetError())
+			sdl.ReleaseGPUTexture(device, gpu_texture)
+			return INVALID_TEXTURE, false
+		}
+		mem.copy(mapped, raw_data(data), int(data_size))
+		sdl.UnmapGPUTransferBuffer(device, transfer)
+
+		cmd_buffer := sdl.AcquireGPUCommandBuffer(device)
+		if cmd_buffer == nil {
+			log.errorf("Failed to acquire command buffer for texture upload: %s", sdl.GetError())
+			sdl.ReleaseGPUTexture(device, gpu_texture)
+			return INVALID_TEXTURE, false
+		}
+		copy_pass := sdl.BeginGPUCopyPass(cmd_buffer)
+		sdl.UploadToGPUTexture(
+			copy_pass,
+			sdl.GPUTextureTransferInfo{transfer_buffer = transfer},
+			sdl.GPUTextureRegion{texture = gpu_texture, w = desc.width, h = desc.height, d = desc.depth_or_layers},
+			false,
+		)
+		sdl.EndGPUCopyPass(copy_pass)
+		if !sdl.SubmitGPUCommandBuffer(cmd_buffer) {
+			log.errorf("Failed to submit texture upload: %s", sdl.GetError())
+			sdl.ReleaseGPUTexture(device, gpu_texture)
+			return INVALID_TEXTURE, false
+		}
+	}
+
+	// Allocate a slot (reuse from free list or append)
+	slot_index: u32
+	if len(GLOB.texture_free_list) > 0 {
+		slot_index = pop(&GLOB.texture_free_list)
+		GLOB.texture_slots[slot_index] = Texture_Slot {
+			gpu_texture = gpu_texture,
+			desc        = desc,
+			generation  = GLOB.texture_slots[slot_index].generation + 1,
+		}
+	} else {
+		slot_index = u32(len(GLOB.texture_slots))
+		append(&GLOB.texture_slots, Texture_Slot{gpu_texture = gpu_texture, desc = desc, generation = 1})
+	}
+
+	return Texture_Id(slot_index), true
+}
+
+// Queue a texture for release at the end of the current frame.
+// The GPU resource is not freed immediately — see "Deferred release" in the README.
+unregister_texture :: proc(id: Texture_Id) {
+	if id == INVALID_TEXTURE do return
+	append(&GLOB.pending_texture_releases, id)
+}
+
+// Re-upload a sub-region of a Dynamic texture.
+update_texture_region :: proc(id: Texture_Id, region: Rectangle, data: []u8) {
+	if id == INVALID_TEXTURE do return
+	slot := &GLOB.texture_slots[u32(id)]
+	if slot.gpu_texture == nil do return
+
+	device := GLOB.device
+	data_size := u32(len(data))
+	if data_size == 0 do return
+
+	transfer := sdl.CreateGPUTransferBuffer(
+		device,
+		sdl.GPUTransferBufferCreateInfo{usage = .UPLOAD, size = data_size},
+	)
+	if transfer == nil {
+		log.errorf("Failed to create transfer buffer for texture region update: %s", sdl.GetError())
+		return
+	}
+	defer sdl.ReleaseGPUTransferBuffer(device, transfer)
+
+	mapped := sdl.MapGPUTransferBuffer(device, transfer, false)
+	if mapped == nil {
+		log.errorf("Failed to map transfer buffer for texture region update: %s", sdl.GetError())
+		return
+	}
+	mem.copy(mapped, raw_data(data), int(data_size))
+	sdl.UnmapGPUTransferBuffer(device, transfer)
+
+	cmd_buffer := sdl.AcquireGPUCommandBuffer(device)
+	if cmd_buffer == nil {
+		log.errorf("Failed to acquire command buffer for texture region update: %s", sdl.GetError())
+		return
+	}
+	copy_pass := sdl.BeginGPUCopyPass(cmd_buffer)
+	sdl.UploadToGPUTexture(
+		copy_pass,
+		sdl.GPUTextureTransferInfo{transfer_buffer = transfer},
+		sdl.GPUTextureRegion {
+			texture = slot.gpu_texture,
+			x = u32(region.x),
+			y = u32(region.y),
+			w = u32(region.width),
+			h = u32(region.height),
+			d = 1,
+		},
+		false,
+	)
+	sdl.EndGPUCopyPass(copy_pass)
+	if !sdl.SubmitGPUCommandBuffer(cmd_buffer) {
+		log.errorf("Failed to submit texture region update: %s", sdl.GetError())
+	}
+}
+
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Helpers -------------
+// ---------------------------------------------------------------------------------------------------------------------
+
+// Compute UV rect, recommended sampler, and inner rect for a given fit mode.
+// `rect` is the target drawing area; `texture_id` identifies the texture whose
+// pixel dimensions are looked up via texture_size().
+// For Fit mode, `inner_rect` is smaller than `rect` (centered). For all other modes, `inner_rect == rect`.
+fit_params :: proc(
+	fit: Fit_Mode,
+	rect: Rectangle,
+	texture_id: Texture_Id,
+) -> (
+	uv_rect: Rectangle,
+	sampler: Sampler_Preset,
+	inner_rect: Rectangle,
+) {
+	size := texture_size(texture_id)
+	texture_width := f32(size.x)
+	texture_height := f32(size.y)
+	rect_width := rect.width
+	rect_height := rect.height
+	inner_rect = rect
+
+	if texture_width == 0 || texture_height == 0 || rect_width == 0 || rect_height == 0 {
+		return {0, 0, 1, 1}, .Linear_Clamp, inner_rect
+	}
+
+	texture_aspect := texture_width / texture_height
+	rect_aspect := rect_width / rect_height
+
+	switch fit {
+	case .Stretch: return {0, 0, 1, 1}, .Linear_Clamp, inner_rect
+
+	case .Fill: if texture_aspect > rect_aspect {
+				// Texture wider than rect — crop sides
+				scale := rect_aspect / texture_aspect
+				margin := (1 - scale) * 0.5
+				return {margin, 0, 1 - margin, 1}, .Linear_Clamp, inner_rect
+			} else {
+				// Texture taller than rect — crop top/bottom
+				scale := texture_aspect / rect_aspect
+				margin := (1 - scale) * 0.5
+				return {0, margin, 1, 1 - margin}, .Linear_Clamp, inner_rect
+			}
+
+	case .Fit:
+		// Preserve aspect, fit inside rect. Returns a shrunken inner_rect.
+		if texture_aspect > rect_aspect {
+			// Image wider — letterbox top/bottom
+			fit_height := rect_width / texture_aspect
+			padding := (rect_height - fit_height) * 0.5
+			inner_rect = Rectangle{rect.x, rect.y + padding, rect_width, fit_height}
+		} else {
+			// Image taller — letterbox left/right
+			fit_width := rect_height * texture_aspect
+			padding := (rect_width - fit_width) * 0.5
+			inner_rect = Rectangle{rect.x + padding, rect.y, fit_width, rect_height}
+		}
+		return {0, 0, 1, 1}, .Linear_Clamp, inner_rect
+
+	case .Tile:
+		uv_width := rect_width / texture_width
+		uv_height := rect_height / texture_height
+		return {0, 0, uv_width, uv_height}, .Linear_Repeat, inner_rect
+
+	case .Center:
+		u_half := rect_width / (2 * texture_width)
+		v_half := rect_height / (2 * texture_height)
+		return {0.5 - u_half, 0.5 - v_half, 0.5 + u_half, 0.5 + v_half}, .Nearest_Clamp, inner_rect
+	}
+
+	return {0, 0, 1, 1}, .Linear_Clamp, inner_rect
+}
+
+texture_size :: proc(id: Texture_Id) -> [2]u32 {
+	if id == INVALID_TEXTURE do return {0, 0}
+	slot := &GLOB.texture_slots[u32(id)]
+	return {slot.desc.width, slot.desc.height}
+}
+
+texture_format :: proc(id: Texture_Id) -> sdl.GPUTextureFormat {
+	if id == INVALID_TEXTURE do return .INVALID
+	return GLOB.texture_slots[u32(id)].desc.format
+}
+
+texture_kind :: proc(id: Texture_Id) -> Texture_Kind {
+	if id == INVALID_TEXTURE do return .Static
+	return GLOB.texture_slots[u32(id)].desc.kind
+}
+
+// Internal: get the raw GPU texture pointer for binding during draw.
+@(private)
+texture_gpu_handle :: proc(id: Texture_Id) -> ^sdl.GPUTexture {
+	if id == INVALID_TEXTURE do return nil
+	idx := u32(id)
+	if idx >= u32(len(GLOB.texture_slots)) do return nil
+	return GLOB.texture_slots[idx].gpu_texture
+}
+
+// Deferred release (called from draw.end / clear_global)
+@(private)
+process_pending_texture_releases :: proc() {
+	device := GLOB.device
+	for id in GLOB.pending_texture_releases {
+		idx := u32(id)
+		if idx >= u32(len(GLOB.texture_slots)) do continue
+		slot := &GLOB.texture_slots[idx]
+		if slot.gpu_texture != nil {
+			sdl.ReleaseGPUTexture(device, slot.gpu_texture)
+			slot.gpu_texture = nil
+		}
+		slot.generation += 1
+		append(&GLOB.texture_free_list, idx)
+	}
+	clear(&GLOB.pending_texture_releases)
+}
+
+@(private)
+get_sampler :: proc(preset: Sampler_Preset) -> ^sdl.GPUSampler {
+	idx := int(preset)
+	if GLOB.samplers[idx] != nil do return GLOB.samplers[idx]
+
+	// Lazily create
+	min_filter, mag_filter: sdl.GPUFilter
+	address_mode: sdl.GPUSamplerAddressMode
+
+	switch preset {
+	case .Nearest_Clamp:
+		min_filter = .NEAREST; mag_filter = .NEAREST; address_mode = .CLAMP_TO_EDGE
+	case .Linear_Clamp:
+		min_filter = .LINEAR; mag_filter = .LINEAR; address_mode = .CLAMP_TO_EDGE
+	case .Nearest_Repeat:
+		min_filter = .NEAREST; mag_filter = .NEAREST; address_mode = .REPEAT
+	case .Linear_Repeat:
+		min_filter = .LINEAR; mag_filter = .LINEAR; address_mode = .REPEAT
+	}
+
+	sampler := sdl.CreateGPUSampler(
+		GLOB.device,
+		sdl.GPUSamplerCreateInfo {
+			min_filter = min_filter,
+			mag_filter = mag_filter,
+			mipmap_mode = .LINEAR,
+			address_mode_u = address_mode,
+			address_mode_v = address_mode,
+			address_mode_w = address_mode,
+		},
+	)
+	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
+	}
+
+	GLOB.samplers[idx] = sampler
+	return sampler
+}
+
+// Internal: destroy all sampler pool entries. Called from draw.destroy().
+@(private)
+destroy_sampler_pool :: proc() {
+	device := GLOB.device
+	for &s in GLOB.samplers {
+		if s != nil {
+			sdl.ReleaseGPUSampler(device, s)
+			s = nil
+		}
+	}
+}
+
+// Internal: destroy all registered textures. Called from draw.destroy().
+@(private)
+destroy_all_textures :: proc() {
+	device := GLOB.device
+	for &slot in GLOB.texture_slots {
+		if slot.gpu_texture != nil {
+			sdl.ReleaseGPUTexture(device, slot.gpu_texture)
+			slot.gpu_texture = nil
+		}
+	}
+	delete(GLOB.texture_slots)
+	delete(GLOB.texture_free_list)
+	delete(GLOB.pending_texture_releases)
+}

meta/main.odin

@@ -1,6 +1,8 @@
 package meta
 
 import "core:fmt"
+import "core:log"
+import "core:mem"
 import "core:os"
 
 Command :: struct {
@@ -20,6 +22,48 @@ COMMANDS :: []Command {
 }
 
 main :: proc() {
+	//----- General setup ----------------------------------
+	when ODIN_DEBUG {
+		// Temp
+		track_temp: mem.Tracking_Allocator
+		mem.tracking_allocator_init(&track_temp, context.temp_allocator)
+		context.temp_allocator = mem.tracking_allocator(&track_temp)
+
+		// Default
+		track: mem.Tracking_Allocator
+		mem.tracking_allocator_init(&track, context.allocator)
+		context.allocator = mem.tracking_allocator(&track)
+		// Log a warning about any memory that was not freed by the end of the program.
+		// This could be fine for some global state or it could be a memory leak.
+		defer {
+			// Temp allocator
+			if len(track_temp.bad_free_array) > 0 {
+				fmt.eprintf("=== %v incorrect frees - temp allocator: ===\n", len(track_temp.bad_free_array))
+				for entry in track_temp.bad_free_array {
+					fmt.eprintf("- %p @ %v\n", entry.memory, entry.location)
+				}
+				mem.tracking_allocator_destroy(&track_temp)
+			}
+			// Default allocator
+			if len(track.allocation_map) > 0 {
+				fmt.eprintf("=== %v allocations not freed - main allocator: ===\n", len(track.allocation_map))
+				for _, entry in track.allocation_map {
+					fmt.eprintf("- %v bytes @ %v\n", entry.size, entry.location)
+				}
+			}
+			if len(track.bad_free_array) > 0 {
+				fmt.eprintf("=== %v incorrect frees - main allocator: ===\n", len(track.bad_free_array))
+				for entry in track.bad_free_array {
+					fmt.eprintf("- %p @ %v\n", entry.memory, entry.location)
+				}
+			}
+			mem.tracking_allocator_destroy(&track)
+		}
+		// Logger
+		context.logger = log.create_console_logger()
+		defer log.destroy_console_logger(context.logger)
+	}
+
 	args := os.args[1:]
 
 	if len(args) == 0 {

qrcode/examples/examples.odin

@@ -1,39 +1,32 @@
 package examples
 
 import "core:fmt"
+import "core:log"
 import "core:mem"
 import "core:os"
 
 import qr ".."
 
 main :: proc() {
-	//----- Tracking allocator ----------------------------------
+	//----- General setup ----------------------------------
 	{
-		tracking_temp_allocator := false
 		// Temp
 		track_temp: mem.Tracking_Allocator
-		if tracking_temp_allocator {
-			mem.tracking_allocator_init(&track_temp, context.temp_allocator)
-			context.temp_allocator = mem.tracking_allocator(&track_temp)
-		}
+		mem.tracking_allocator_init(&track_temp, context.temp_allocator)
+		context.temp_allocator = mem.tracking_allocator(&track_temp)
+
 		// Default
 		track: mem.Tracking_Allocator
 		mem.tracking_allocator_init(&track, context.allocator)
 		context.allocator = mem.tracking_allocator(&track)
+		// Log a warning about any memory that was not freed by the end of the program.
+		// This could be fine for some global state or it could be a memory leak.
 		defer {
 			// Temp allocator
-			if tracking_temp_allocator {
-				if len(track_temp.allocation_map) > 0 {
-					fmt.eprintf("=== %v allocations not freed - temp allocator: ===\n", len(track_temp.allocation_map))
-					for _, entry in track_temp.allocation_map {
-						fmt.eprintf("- %v bytes @ %v\n", entry.size, entry.location)
-					}
-				}
-				if len(track_temp.bad_free_array) > 0 {
-					fmt.eprintf("=== %v incorrect frees - temp allocator: ===\n", len(track_temp.bad_free_array))
-					for entry in track_temp.bad_free_array {
-						fmt.eprintf("- %p @ %v\n", entry.memory, entry.location)
-					}
+			if len(track_temp.bad_free_array) > 0 {
+				fmt.eprintf("=== %v incorrect frees - temp allocator: ===\n", len(track_temp.bad_free_array))
+				for entry in track_temp.bad_free_array {
+					fmt.eprintf("- %p @ %v\n", entry.memory, entry.location)
 				}
 				mem.tracking_allocator_destroy(&track_temp)
 			}
@@ -52,6 +45,9 @@ main :: proc() {
 			}
 			mem.tracking_allocator_destroy(&track)
 		}
+		// Logger
+		context.logger = log.create_console_logger()
+		defer log.destroy_console_logger(context.logger)
 	}
 
 	args := os.args
@@ -73,57 +69,32 @@ main :: proc() {
 	}
 }
 
-// -------------------------------------------------------------------------------------------------
-// Utilities
-// -------------------------------------------------------------------------------------------------
-
-// Prints the given QR Code to the console.
-print_qr :: proc(qrcode: []u8) {
-	size := qr.get_size(qrcode)
-	border :: 4
-	for y in -border ..< size + border {
-		for x in -border ..< size + border {
-			fmt.print("##" if qr.get_module(qrcode, x, y) else "  ")
-		}
-		fmt.println()
-	}
-	fmt.println()
-}
-
-// -------------------------------------------------------------------------------------------------
-// Demo: Basic
-// -------------------------------------------------------------------------------------------------
-
 // Creates a single QR Code, then prints it to the console.
 basic :: proc() {
 	text :: "Hello, world!"
 	ecl :: qr.Ecc.Low
 
 	qrcode: [qr.BUFFER_LEN_MAX]u8
-	ok := qr.encode(text, qrcode[:], ecl)
+	ok := qr.encode_auto(text, qrcode[:], ecl)
 	if ok do print_qr(qrcode[:])
 }
 
-// -------------------------------------------------------------------------------------------------
-// Demo: Variety
-// -------------------------------------------------------------------------------------------------
-
 // Creates a variety of QR Codes that exercise different features of the library.
 variety :: proc() {
 	qrcode: [qr.BUFFER_LEN_MAX]u8
 
 	{ 	// Numeric mode encoding (3.33 bits per digit)
-		ok := qr.encode("314159265358979323846264338327950288419716939937510", qrcode[:], qr.Ecc.Medium)
+		ok := qr.encode_auto("314159265358979323846264338327950288419716939937510", qrcode[:], qr.Ecc.Medium)
 		if ok do print_qr(qrcode[:])
 	}
 
 	{ 	// Alphanumeric mode encoding (5.5 bits per character)
-		ok := qr.encode("DOLLAR-AMOUNT:$39.87 PERCENTAGE:100.00% OPERATIONS:+-*/", qrcode[:], qr.Ecc.High)
+		ok := qr.encode_auto("DOLLAR-AMOUNT:$39.87 PERCENTAGE:100.00% OPERATIONS:+-*/", qrcode[:], qr.Ecc.High)
 		if ok do print_qr(qrcode[:])
 	}
 
 	{ 	// Unicode text as UTF-8
-		ok := qr.encode(
+		ok := qr.encode_auto(
 			"\xE3\x81\x93\xE3\x82\x93\xE3\x81\xAB\xE3\x81\xA1wa\xE3\x80\x81" +
 			"\xE4\xB8\x96\xE7\x95\x8C\xEF\xBC\x81\x20\xCE\xB1\xCE\xB2\xCE\xB3\xCE\xB4",
 			qrcode[:],
@@ -133,7 +104,7 @@ variety :: proc() {
 	}
 
 	{ 	// Moderately large QR Code using longer text (from Lewis Carroll's Alice in Wonderland)
-		ok := qr.encode(
+		ok := qr.encode_auto(
 			"Alice was beginning to get very tired of sitting by her sister on the bank, " +
 			"and of having nothing to do: once or twice she had peeped into the book her sister was reading, " +
 			"but it had no pictures or conversations in it, 'and what is the use of a book,' thought Alice " +
@@ -148,10 +119,6 @@ variety :: proc() {
 	}
 }
 
-// -------------------------------------------------------------------------------------------------
-// Demo: Segment
-// -------------------------------------------------------------------------------------------------
-
 // Creates QR Codes with manually specified segments for better compactness.
 segment :: proc() {
 	qrcode: [qr.BUFFER_LEN_MAX]u8
@@ -163,7 +130,7 @@ segment :: proc() {
 		// Encode as single text (auto mode selection)
 		{
 			concat :: silver0 + silver1
-			ok := qr.encode(concat, qrcode[:], qr.Ecc.Low)
+			ok := qr.encode_auto(concat, qrcode[:], qr.Ecc.Low)
 			if ok do print_qr(qrcode[:])
 		}
 
@@ -172,7 +139,7 @@ segment :: proc() {
 			seg_buf0: [qr.BUFFER_LEN_MAX]u8
 			seg_buf1: [qr.BUFFER_LEN_MAX]u8
 			segs := [2]qr.Segment{qr.make_alphanumeric(silver0, seg_buf0[:]), qr.make_numeric(silver1, seg_buf1[:])}
-			ok := qr.encode(segs[:], qr.Ecc.Low, qrcode[:])
+			ok := qr.encode_auto(segs[:], qr.Ecc.Low, qrcode[:])
 			if ok do print_qr(qrcode[:])
 		}
 	}
@@ -185,7 +152,7 @@ segment :: proc() {
 		// Encode as single text (auto mode selection)
 		{
 			concat :: golden0 + golden1 + golden2
-			ok := qr.encode(concat, qrcode[:], qr.Ecc.Low)
+			ok := qr.encode_auto(concat, qrcode[:], qr.Ecc.Low)
 			if ok do print_qr(qrcode[:])
 		}
 
@@ -201,7 +168,7 @@ segment :: proc() {
 				qr.make_numeric(golden1, seg_buf1[:]),
 				qr.make_alphanumeric(golden2, seg_buf2[:]),
 			}
-			ok := qr.encode(segs[:], qr.Ecc.Low, qrcode[:])
+			ok := qr.encode_auto(segs[:], qr.Ecc.Low, qrcode[:])
 			if ok do print_qr(qrcode[:])
 		}
 	}
@@ -219,7 +186,7 @@ segment :: proc() {
 				"\xEF\xBD\x84\xEF\xBD\x85\xEF\xBD\x93\xEF" +
 				"\xBD\x95\xE3\x80\x80\xCE\xBA\xCE\xB1\xEF" +
 				"\xBC\x9F"
-			ok := qr.encode(madoka, qrcode[:], qr.Ecc.Low)
+			ok := qr.encode_auto(madoka, qrcode[:], qr.Ecc.Low)
 			if ok do print_qr(qrcode[:])
 		}
 
@@ -254,16 +221,12 @@ segment :: proc() {
 			seg.data = seg_buf[:(seg.bit_length + 7) / 8]
 
 			segs := [1]qr.Segment{seg}
-			ok := qr.encode(segs[:], qr.Ecc.Low, qrcode[:])
+			ok := qr.encode_auto(segs[:], qr.Ecc.Low, qrcode[:])
 			if ok do print_qr(qrcode[:])
 		}
 	}
 }
 
-// -------------------------------------------------------------------------------------------------
-// Demo: Mask
-// -------------------------------------------------------------------------------------------------
-
 // Creates QR Codes with the same size and contents but different mask patterns.
 mask :: proc() {
 	qrcode: [qr.BUFFER_LEN_MAX]u8
@@ -271,10 +234,10 @@ mask :: proc() {
 	{ 	// Project Nayuki URL
 		ok: bool
 
-		ok = qr.encode("https://www.nayuki.io/", qrcode[:], qr.Ecc.High)
+		ok = qr.encode_auto("https://www.nayuki.io/", qrcode[:], qr.Ecc.High)
 		if ok do print_qr(qrcode[:])
 
-		ok = qr.encode("https://www.nayuki.io/", qrcode[:], qr.Ecc.High, mask = qr.Mask.M3)
+		ok = qr.encode_auto("https://www.nayuki.io/", qrcode[:], qr.Ecc.High, mask = qr.Mask.M3)
 		if ok do print_qr(qrcode[:])
 	}
 
@@ -290,16 +253,29 @@ mask :: proc() {
 
 		ok: bool
 
-		ok = qr.encode(text, qrcode[:], qr.Ecc.Medium, mask = qr.Mask.M0)
+		ok = qr.encode_auto(text, qrcode[:], qr.Ecc.Medium, mask = qr.Mask.M0)
 		if ok do print_qr(qrcode[:])
 
-		ok = qr.encode(text, qrcode[:], qr.Ecc.Medium, mask = qr.Mask.M1)
+		ok = qr.encode_auto(text, qrcode[:], qr.Ecc.Medium, mask = qr.Mask.M1)
 		if ok do print_qr(qrcode[:])
 
-		ok = qr.encode(text, qrcode[:], qr.Ecc.Medium, mask = qr.Mask.M5)
+		ok = qr.encode_auto(text, qrcode[:], qr.Ecc.Medium, mask = qr.Mask.M5)
 		if ok do print_qr(qrcode[:])
 
-		ok = qr.encode(text, qrcode[:], qr.Ecc.Medium, mask = qr.Mask.M7)
+		ok = qr.encode_auto(text, qrcode[:], qr.Ecc.Medium, mask = qr.Mask.M7)
 		if ok do print_qr(qrcode[:])
 	}
 }
+
+// Prints the given QR Code to the console.
+print_qr :: proc(qrcode: []u8) {
+	size := qr.get_size(qrcode)
+	border :: 4
+	for y in -border ..< size + border {
+		for x in -border ..< size + border {
+			fmt.print("##" if qr.get_module(qrcode, x, y) else "  ")
+		}
+		fmt.println()
+	}
+	fmt.println()
+}

qrcode/generate.odin

@@ -2,10 +2,30 @@ package qrcode
 
 import "core:slice"
 
+VERSION_MIN :: 1
+VERSION_MAX :: 40
 
-// -------------------------------------------------------------------------------------------------
-// Types
-// -------------------------------------------------------------------------------------------------
+// The worst-case number of bytes needed to store one QR Code, up to and including version 40.
+BUFFER_LEN_MAX :: 3918 // buffer_len_for_version(VERSION_MAX)
+
+// Returns the number of bytes needed to store any QR Code up to and including the given version.
+buffer_len_for_version :: #force_inline proc(n: int) -> int {
+	size := n * 4 + 17
+	return (size * size + 7) / 8 + 1
+}
+
+@(private)
+LENGTH_OVERFLOW :: -1
+@(private)
+REED_SOLOMON_DEGREE_MAX :: 30
+@(private)
+PENALTY_N1 :: 3
+@(private)
+PENALTY_N2 :: 3
+@(private)
+PENALTY_N3 :: 40
+@(private)
+PENALTY_N4 :: 10
 
 // The error correction level in a QR Code symbol.
 Ecc :: enum {
@@ -44,39 +64,6 @@ Segment :: struct {
 	bit_length: int,
 }
 
-// -------------------------------------------------------------------------------------------------
-// Constants
-// -------------------------------------------------------------------------------------------------
-
-VERSION_MIN :: 1
-VERSION_MAX :: 40
-
-// The worst-case number of bytes needed to store one QR Code, up to and including version 40.
-BUFFER_LEN_MAX :: 3918 // buffer_len_for_version(VERSION_MAX)
-
-// Returns the number of bytes needed to store any QR Code up to and including the given version.
-buffer_len_for_version :: #force_inline proc(n: int) -> int {
-	size := n * 4 + 17
-	return (size * size + 7) / 8 + 1
-}
-
-// -------------------------------------------------------------------------------------------------
-// Private constants
-// -------------------------------------------------------------------------------------------------
-
-@(private)
-LENGTH_OVERFLOW :: -1
-@(private)
-REED_SOLOMON_DEGREE_MAX :: 30
-@(private)
-PENALTY_N1 :: 3
-@(private)
-PENALTY_N2 :: 3
-@(private)
-PENALTY_N3 :: 40
-@(private)
-PENALTY_N4 :: 10
-
 //odinfmt: disable
 // For generating error correction codes. Index 0 is padding (set to illegal value).
 @(private)
@@ -96,10 +83,9 @@ NUM_ERROR_CORRECTION_BLOCKS := [4][41]i8{
 }
 //odinfmt: enable
 
-
-// -------------------------------------------------------------------------------------------------
-// Encode procedures
-// -------------------------------------------------------------------------------------------------
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Encode Procedures ------------------------
+// ---------------------------------------------------------------------------------------------------------------------
 
 // Encodes the given text string to a QR Code, automatically selecting
 // numeric, alphanumeric, or byte mode based on content.
@@ -117,7 +103,7 @@ NUM_ERROR_CORRECTION_BLOCKS := [4][41]i8{
 //   - The text cannot fit in any version within [min_version, max_version] at the given ECL.
 //   - The encoded segment data exceeds the buffer capacity.
 @(require_results)
-encode_text_explicit_temp :: proc(
+encode_text_manual :: proc(
 	text: string,
 	temp_buffer, qrcode: []u8,
 	ecl: Ecc,
@@ -130,7 +116,7 @@ encode_text_explicit_temp :: proc(
 ) {
 	text_len := len(text)
 	if text_len == 0 {
-		return encode_segments_advanced_explicit_temp(
+		return encode_segments_advanced_manual(
 			nil,
 			ecl,
 			min_version,
@@ -162,7 +148,7 @@ encode_text_explicit_temp :: proc(
 			seg.data = temp_buffer[:text_len]
 		}
 		segs := [1]Segment{seg}
-		return encode_segments_advanced_explicit_temp(
+		return encode_segments_advanced_manual(
 			segs[:],
 			ecl,
 			min_version,
@@ -211,13 +197,9 @@ encode_text_auto :: proc(
 		return false
 	}
 	defer delete(temp_buffer, temp_allocator)
-	return encode_text_explicit_temp(text, temp_buffer, qrcode, ecl, min_version, max_version, mask, boost_ecl)
+	return encode_text_manual(text, temp_buffer, qrcode, ecl, min_version, max_version, mask, boost_ecl)
 }
 
-encode_text :: proc {
-	encode_text_explicit_temp,
-	encode_text_auto,
-}
 
 // Encodes arbitrary binary data to a QR Code using byte mode.
 //
@@ -234,7 +216,7 @@ encode_text :: proc {
 // Returns ok=false when:
 //   - The payload cannot fit in any version within [min_version, max_version] at the given ECL.
 @(require_results)
-encode_binary :: proc(
+encode_binary_manual :: proc(
 	data_and_temp: []u8,
 	data_len: int,
 	qrcode: []u8,
@@ -256,7 +238,7 @@ encode_binary :: proc(
 	seg.num_chars = data_len
 	seg.data = data_and_temp[:data_len]
 	segs := [1]Segment{seg}
-	return encode_segments_advanced(
+	return encode_segments_advanced_manual(
 		segs[:],
 		ecl,
 		min_version,
@@ -268,6 +250,55 @@ encode_binary :: proc(
 	)
 }
 
+// Encodes arbitrary binary data to a QR Code using byte mode,
+// automatically allocating and freeing the temp buffer.
+//
+// Parameters:
+//   bin_data       - [in]  Payload bytes (aliased by the internal segment; not modified).
+//   qrcode         - [out] On success, contains the encoded QR Code. On failure, qrcode[0] is
+//                          set to 0.
+//   temp_allocator - Allocator used for the internal scratch buffer. Freed before return.
+//
+// qrcode must have length >= buffer_len_for_version(max_version).
+//
+// Returns ok=false when:
+//   - The payload cannot fit in any version within [min_version, max_version] at the given ECL.
+//   - The temp_allocator fails to allocate.
+@(require_results)
+encode_binary_auto :: proc(
+	bin_data: []u8,
+	qrcode: []u8,
+	ecl: Ecc,
+	min_version: int = VERSION_MIN,
+	max_version: int = VERSION_MAX,
+	mask: Maybe(Mask) = nil,
+	boost_ecl: bool = true,
+	temp_allocator := context.temp_allocator,
+) -> (
+	ok: bool,
+) {
+	seg: Segment
+	seg.mode = .Byte
+	seg.bit_length = calc_segment_bit_length(.Byte, len(bin_data))
+	if seg.bit_length == LENGTH_OVERFLOW {
+		qrcode[0] = 0
+		return false
+	}
+	seg.num_chars = len(bin_data)
+	seg.data = bin_data
+	segs := [1]Segment{seg}
+	return encode_segments_advanced_auto(
+		segs[:],
+		ecl,
+		min_version,
+		max_version,
+		mask,
+		boost_ecl,
+		qrcode,
+		temp_allocator,
+	)
+}
+
 // Encodes the given segments to a QR Code using default parameters
 // (VERSION_MIN..VERSION_MAX, auto mask, boost ECL).
 //
@@ -282,17 +313,8 @@ encode_binary :: proc(
 // Returns ok=false when:
 //   - The total segment data exceeds the capacity of version 40 at the given ECL.
 @(require_results)
-encode_segments_explicit_temp :: proc(segs: []Segment, ecl: Ecc, temp_buffer, qrcode: []u8) -> (ok: bool) {
-	return encode_segments_advanced_explicit_temp(
-		segs,
-		ecl,
-		VERSION_MIN,
-		VERSION_MAX,
-		nil,
-		true,
-		temp_buffer,
-		qrcode,
-	)
+encode_segments_manual :: proc(segs: []Segment, ecl: Ecc, temp_buffer, qrcode: []u8) -> (ok: bool) {
+	return encode_segments_advanced_manual(segs, ecl, VERSION_MIN, VERSION_MAX, nil, true, temp_buffer, qrcode)
 }
 
 // Encodes segments to a QR Code using default parameters, automatically allocating the temp buffer.
@@ -328,13 +350,9 @@ encode_segments_auto :: proc(
 		return false
 	}
 	defer delete(temp_buffer, temp_allocator)
-	return encode_segments_explicit_temp(segs, ecl, temp_buffer, qrcode)
+	return encode_segments_manual(segs, ecl, temp_buffer, qrcode)
 }
 
-encode_segments :: proc {
-	encode_segments_explicit_temp,
-	encode_segments_auto,
-}
 
 // Encodes the given segments to a QR Code with full control over version range, mask, and ECL boosting.
 //
@@ -353,7 +371,7 @@ encode_segments :: proc {
 //   - The total segment data exceeds the capacity of every version in [min_version, max_version]
 //     at the given ECL.
 @(require_results)
-encode_segments_advanced_explicit_temp :: proc(
+encode_segments_advanced_manual :: proc(
 	segs: []Segment,
 	ecl: Ecc,
 	min_version, max_version: int,
@@ -490,7 +508,7 @@ encode_segments_advanced_auto :: proc(
 		return false
 	}
 	defer delete(temp_buffer, temp_allocator)
-	return encode_segments_advanced_explicit_temp(
+	return encode_segments_advanced_manual(
 		segs,
 		ecl,
 		min_version,
@@ -502,24 +520,24 @@ encode_segments_advanced_auto :: proc(
 	)
 }
 
-encode_segments_advanced :: proc {
-	encode_segments_advanced_explicit_temp,
-	encode_segments_advanced_auto,
+encode_manual :: proc {
+	encode_text_manual,
+	encode_binary_manual,
+	encode_segments_manual,
+	encode_segments_advanced_manual,
 }
 
-encode :: proc {
-	encode_text_explicit_temp,
+encode_auto :: proc {
 	encode_text_auto,
-	encode_binary,
-	encode_segments_explicit_temp,
+	encode_binary_auto,
 	encode_segments_auto,
-	encode_segments_advanced_explicit_temp,
 	encode_segments_advanced_auto,
 }
 
-// -------------------------------------------------------------------------------------------------
-// Error correction code generation
-// -------------------------------------------------------------------------------------------------
+
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Error Correction Code Generation ------------------------
+// ---------------------------------------------------------------------------------------------------------------------
 
 // Appends error correction bytes to each block of data, then interleaves bytes from all blocks.
 @(private)
@@ -587,10 +605,6 @@ get_num_raw_data_modules :: proc(ver: int) -> int {
 	return result
 }
 
-// -------------------------------------------------------------------------------------------------
-// Reed-Solomon ECC generator
-// -------------------------------------------------------------------------------------------------
-
 @(private)
 reed_solomon_compute_divisor :: proc(degree: int, result: []u8) {
 	assert(1 <= degree && degree <= REED_SOLOMON_DEGREE_MAX, "reed-solomon degree out of range")
@@ -637,9 +651,9 @@ reed_solomon_multiply :: proc(x, y: u8) -> u8 {
 	return z
 }
 
-// -------------------------------------------------------------------------------------------------
-// Drawing function modules
-// -------------------------------------------------------------------------------------------------
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Drawing Function Modules ------------------------
+// ---------------------------------------------------------------------------------------------------------------------
 
 // Clears the QR Code grid and marks every function module as dark.
 @(private)
@@ -785,9 +799,9 @@ fill_rectangle :: proc(left, top, width, height: int, qrcode: []u8) {
 	}
 }
 
-// -------------------------------------------------------------------------------------------------
-// Drawing data modules and masking
-// -------------------------------------------------------------------------------------------------
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Drawing data modules and masking ------------------------
+// ---------------------------------------------------------------------------------------------------------------------
 
 @(private)
 draw_codewords :: proc(data: []u8, data_len: int, qrcode: []u8) {
@@ -965,9 +979,9 @@ finder_penalty_add_history :: proc(current_run_length: int, run_history: ^[7]int
 	run_history[0] = current_run_length
 }
 
-// -------------------------------------------------------------------------------------------------
-// Basic QR Code information
-// -------------------------------------------------------------------------------------------------
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Basic QR code information ------------------------
+// ---------------------------------------------------------------------------------------------------------------------
 
 // Returns the minimum buffer size (in bytes) needed for both temp_buffer and qrcode
 // to encode the given content at the given ECC level within the given version range.
@@ -981,7 +995,7 @@ min_buffer_size :: proc {
 	min_buffer_size_segments,
 }
 
-// Text path: auto-selects numeric/alphanumeric/byte mode the same way encode_text does.
+// Text path: auto-selects numeric/alphanumeric/byte mode the same way encode_text_manual does.
 //
 // Returns ok=false when:
 //   - The text exceeds QR Code capacity for every version in the range at the given ECL.
@@ -1127,9 +1141,9 @@ get_bit :: #force_inline proc(x: int, i: uint) -> bool {
 	return ((x >> i) & 1) != 0
 }
 
-// -------------------------------------------------------------------------------------------------
-// Segment handling
-// -------------------------------------------------------------------------------------------------
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Segment Handling ------------------------
+// ---------------------------------------------------------------------------------------------------------------------
 
 // Tests whether the given string can be encoded in numeric mode.
 is_numeric :: proc(text: string) -> bool {
@@ -1162,7 +1176,6 @@ calc_segment_buffer_size :: proc(mode: Mode, num_chars: int) -> int {
 	return (temp + 7) / 8
 }
 
-@(private)
 calc_segment_bit_length :: proc(mode: Mode, num_chars: int) -> int {
 	if num_chars < 0 || num_chars > 32767 {
 		return LENGTH_OVERFLOW
@@ -1319,11 +1332,11 @@ make_eci :: proc(assign_val: int, buf: []u8) -> Segment {
 	return result
 }
 
-// -------------------------------------------------------------------------------------------------
-// Private helpers
-// -------------------------------------------------------------------------------------------------
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Helpers ------------------------
+// ---------------------------------------------------------------------------------------------------------------------
 
-@(private)
+// Internal
 append_bits_to_buffer :: proc(val: uint, num_bits: int, buffer: []u8, bit_len: ^int) {
 	assert(0 <= num_bits && num_bits <= 16 && val >> uint(num_bits) == 0, "invalid bit count or value overflow")
 	for i := num_bits - 1; i >= 0; i -= 1 {
@@ -1332,7 +1345,7 @@ append_bits_to_buffer :: proc(val: uint, num_bits: int, buffer: []u8, bit_len: ^
 	}
 }
 
-@(private)
+// Internal
 get_total_bits :: proc(segs: []Segment, version: int) -> int {
 	result := 0
 	for &seg in segs {
@@ -1354,7 +1367,7 @@ get_total_bits :: proc(segs: []Segment, version: int) -> int {
 	return result
 }
 
-@(private)
+// Internal
 num_char_count_bits :: proc(mode: Mode, version: int) -> int {
 	assert(VERSION_MIN <= version && version <= VERSION_MAX, "version out of bounds")
 	i := (version + 7) / 17
@@ -1376,8 +1389,8 @@ num_char_count_bits :: proc(mode: Mode, version: int) -> int {
 	unreachable()
 }
 
+// Internal
 // Returns the index of c in the alphanumeric charset (0-44), or -1 if not found.
-@(private)
 alphanumeric_index :: proc(c: u8) -> int {
 	switch c {
 	case '0' ..= '9': return int(c - '0')
@@ -2487,7 +2500,7 @@ test_min_buffer_size_text :: proc(t: ^testing.T) {
 		testing.expect(t, planned > 0)
 		qrcode: [BUFFER_LEN_MAX]u8
 		temp: [BUFFER_LEN_MAX]u8
-		ok := encode_text(text, temp[:], qrcode[:], Ecc.Low)
+		ok := encode_text_manual(text, temp[:], qrcode[:], Ecc.Low)
 		testing.expect(t, ok)
 		actual_version_size := get_size(qrcode[:])
 		actual_buf_len := buffer_len_for_version((actual_version_size - 17) / 4)
@@ -2538,7 +2551,7 @@ test_min_buffer_size_binary :: proc(t: ^testing.T) {
 	testing.expect(t, size > 0)
 	testing.expect(t, size <= buffer_len_for_version(2))
 
-	// Verify agreement with encode_binary
+	// Verify agreement with encode_binary_manual
 	{
 		data_len :: 100
 		planned, planned_ok := min_buffer_size(data_len, .Medium)
@@ -2549,7 +2562,7 @@ test_min_buffer_size_binary :: proc(t: ^testing.T) {
 		for i in 0 ..< data_len {
 			dat[i] = u8(i)
 		}
-		ok := encode_binary(dat[:], data_len, qrcode[:], .Medium)
+		ok := encode_binary_manual(dat[:], data_len, qrcode[:], .Medium)
 		testing.expect(t, ok)
 		actual_version_size := get_size(qrcode[:])
 		actual_buf_len := buffer_len_for_version((actual_version_size - 17) / 4)
@@ -2609,7 +2622,7 @@ test_min_buffer_size_segments :: proc(t: ^testing.T) {
 		// Verify against actual encode
 		qrcode: [BUFFER_LEN_MAX]u8
 		temp: [BUFFER_LEN_MAX]u8
-		ok := encode_segments(segs[:], Ecc.Low, temp[:], qrcode[:])
+		ok := encode_segments_manual(segs[:], Ecc.Low, temp[:], qrcode[:])
 		testing.expect(t, ok)
 		actual_version_size := get_size(qrcode[:])
 		actual_buf_len := buffer_len_for_version((actual_version_size - 17) / 4)
@@ -2631,7 +2644,7 @@ test_encode_text_auto :: proc(t: ^testing.T) {
 		text :: "Hello, world!"
 		qr_explicit: [BUFFER_LEN_MAX]u8
 		temp: [BUFFER_LEN_MAX]u8
-		ok_explicit := encode_text_explicit_temp(text, temp[:], qr_explicit[:], .Low)
+		ok_explicit := encode_text_manual(text, temp[:], qr_explicit[:], .Low)
 		testing.expect(t, ok_explicit)
 
 		qr_auto: [BUFFER_LEN_MAX]u8
@@ -2650,7 +2663,7 @@ test_encode_text_auto :: proc(t: ^testing.T) {
 		text :: "314159265358979323846264338327950288419716939937510"
 		qr_explicit: [BUFFER_LEN_MAX]u8
 		temp: [BUFFER_LEN_MAX]u8
-		ok_explicit := encode_text_explicit_temp(text, temp[:], qr_explicit[:], .Medium)
+		ok_explicit := encode_text_manual(text, temp[:], qr_explicit[:], .Medium)
 		testing.expect(t, ok_explicit)
 
 		qr_auto: [BUFFER_LEN_MAX]u8
@@ -2669,7 +2682,7 @@ test_encode_text_auto :: proc(t: ^testing.T) {
 		text :: "HELLO WORLD"
 		qr_explicit: [BUFFER_LEN_MAX]u8
 		temp: [BUFFER_LEN_MAX]u8
-		ok_explicit := encode_text_explicit_temp(text, temp[:], qr_explicit[:], .Quartile)
+		ok_explicit := encode_text_manual(text, temp[:], qr_explicit[:], .Quartile)
 		testing.expect(t, ok_explicit)
 
 		qr_auto: [BUFFER_LEN_MAX]u8
@@ -2695,7 +2708,7 @@ test_encode_text_auto :: proc(t: ^testing.T) {
 		text :: "https://www.nayuki.io/"
 		qr_explicit: [BUFFER_LEN_MAX]u8
 		temp: [BUFFER_LEN_MAX]u8
-		ok_explicit := encode_text_explicit_temp(text, temp[:], qr_explicit[:], .High, mask = .M3)
+		ok_explicit := encode_text_manual(text, temp[:], qr_explicit[:], .High, mask = .M3)
 		testing.expect(t, ok_explicit)
 
 		qr_auto: [BUFFER_LEN_MAX]u8
@@ -2732,7 +2745,7 @@ test_encode_segments_auto :: proc(t: ^testing.T) {
 
 		qr_explicit: [BUFFER_LEN_MAX]u8
 		temp: [BUFFER_LEN_MAX]u8
-		ok_explicit := encode_segments_explicit_temp(segs[:], .Low, temp[:], qr_explicit[:])
+		ok_explicit := encode_segments_manual(segs[:], .Low, temp[:], qr_explicit[:])
 		testing.expect(t, ok_explicit)
 
 		qr_auto: [BUFFER_LEN_MAX]u8
@@ -2764,7 +2777,7 @@ test_encode_segments_advanced_auto :: proc(t: ^testing.T) {
 
 		qr_explicit: [BUFFER_LEN_MAX]u8
 		temp: [BUFFER_LEN_MAX]u8
-		ok_explicit := encode_segments_advanced_explicit_temp(
+		ok_explicit := encode_segments_advanced_manual(
 			segs[:],
 			.Medium,
 			VERSION_MIN,
@@ -2795,7 +2808,7 @@ test_encode_segments_advanced_auto :: proc(t: ^testing.T) {
 
 		qr_explicit: [BUFFER_LEN_MAX]u8
 		temp: [BUFFER_LEN_MAX]u8
-		ok_explicit := encode_segments_advanced_explicit_temp(
+		ok_explicit := encode_segments_advanced_manual(
 			segs[:],
 			.High,
 			1,

vendor/lmdb/examples/examples.odin

@@ -1,8 +1,11 @@
 package examples
 
 import "core:fmt"
+import "core:log"
+import "core:mem"
 import "core:os"
 import "core:sys/posix"
+
 import mdb "../../lmdb"
 
 // 0o660
@@ -10,34 +13,75 @@ DB_MODE :: posix.mode_t{.IWGRP, .IRGRP, .IWUSR, .IRUSR}
 DB_PATH :: "out/debug/lmdb_example_db"
 
 main :: proc() {
-    environment: ^mdb.Env
+	//----- General setup ----------------------------------
+	{
+		// Temp
+		track_temp: mem.Tracking_Allocator
+		mem.tracking_allocator_init(&track_temp, context.temp_allocator)
+		context.temp_allocator = mem.tracking_allocator(&track_temp)
 
-    // Create environment for lmdb
-    mdb.panic_on_err(mdb.env_create(&environment))
-    // Create directory for databases. Won't do anything if it already exists.
-    // 0o774 gives all permissions for owner and group, read for everyone else.
-    os.make_directory(DB_PATH, 0o774)
-    // Open the database files (creates them if they don't already exist)
-    mdb.panic_on_err(mdb.env_open(environment, DB_PATH, 0, DB_MODE))
+		// Default
+		track: mem.Tracking_Allocator
+		mem.tracking_allocator_init(&track, context.allocator)
+		context.allocator = mem.tracking_allocator(&track)
+		// Log a warning about any memory that was not freed by the end of the program.
+		// This could be fine for some global state or it could be a memory leak.
+		defer {
+			// Temp allocator
+			if len(track_temp.bad_free_array) > 0 {
+				fmt.eprintf("=== %v incorrect frees - temp allocator: ===\n", len(track_temp.bad_free_array))
+				for entry in track_temp.bad_free_array {
+					fmt.eprintf("- %p @ %v\n", entry.memory, entry.location)
+				}
+				mem.tracking_allocator_destroy(&track_temp)
+			}
+			// Default allocator
+			if len(track.allocation_map) > 0 {
+				fmt.eprintf("=== %v allocations not freed - main allocator: ===\n", len(track.allocation_map))
+				for _, entry in track.allocation_map {
+					fmt.eprintf("- %v bytes @ %v\n", entry.size, entry.location)
+				}
+			}
+			if len(track.bad_free_array) > 0 {
+				fmt.eprintf("=== %v incorrect frees - main allocator: ===\n", len(track.bad_free_array))
+				for entry in track.bad_free_array {
+					fmt.eprintf("- %p @ %v\n", entry.memory, entry.location)
+				}
+			}
+			mem.tracking_allocator_destroy(&track)
+		}
+		// Logger
+		context.logger = log.create_console_logger()
+		defer log.destroy_console_logger(context.logger)
+	}
 
-    // Transactions
-    txn_handle: ^mdb.Txn
-    db_handle: mdb.Dbi
-    // Put transaction
-    key := 7
-    key_val := mdb.autoval(&key)
-    put_data := 12
-    put_data_val := mdb.autoval(&put_data)
-    mdb.panic_on_err(mdb.txn_begin(environment, nil, 0, &txn_handle))
-    mdb.panic_on_err(mdb.dbi_open(txn_handle, nil, 0, &db_handle))
-    mdb.panic_on_err(mdb.put(txn_handle, db_handle, &key_val.raw, &put_data_val.raw, 0))
-    mdb.panic_on_err(mdb.txn_commit(txn_handle))
+	environment: ^mdb.Env
 
-    // Get transaction
-    get_data_val := mdb.nil_autoval(int)
-    mdb.panic_on_err(mdb.txn_begin(environment, nil, 0, &txn_handle))
-    mdb.panic_on_err(mdb.get(txn_handle, db_handle, &key_val.raw, &get_data_val.raw))
-    mdb.panic_on_err(mdb.txn_commit(txn_handle))
-    data_cpy := mdb.autoval_get_data(&get_data_val)^
-    fmt.println("Get result:", data_cpy)
+	// Create environment for lmdb
+	mdb.panic_on_err(mdb.env_create(&environment))
+	// Create directory for databases. Won't do anything if it already exists.
+	os.make_directory(DB_PATH)
+	// Open the database files (creates them if they don't already exist)
+	mdb.panic_on_err(mdb.env_open(environment, DB_PATH, {}, DB_MODE))
+
+	// Transactions
+	txn_handle: ^mdb.Txn
+	db_handle: mdb.Dbi
+	// Put transaction
+	key := 7
+	key_val := mdb.blittable_val(&key)
+	put_data := 12
+	put_data_val := mdb.blittable_val(&put_data)
+	mdb.panic_on_err(mdb.txn_begin(environment, nil, {}, &txn_handle))
+	mdb.panic_on_err(mdb.dbi_open(txn_handle, nil, {}, &db_handle))
+	mdb.panic_on_err(mdb.put(txn_handle, db_handle, &key_val, &put_data_val, {}))
+	mdb.panic_on_err(mdb.txn_commit(txn_handle))
+
+	// Get transaction
+	data_val: mdb.Val
+	mdb.panic_on_err(mdb.txn_begin(environment, nil, {}, &txn_handle))
+	mdb.panic_on_err(mdb.get(txn_handle, db_handle, &key_val, &data_val))
+	data_cpy := mdb.blittable_copy(&data_val, int)
+	mdb.panic_on_err(mdb.txn_commit(txn_handle))
+	fmt.println("Get result:", data_cpy)
 }

vendor/lmdb/lmdb.odin

@@ -164,24 +164,123 @@
 */
 package lmdb
 
-foreign import lib "system:lmdb"
-
 import "core:c"
 import "core:fmt"
+import "core:reflect"
 import "core:sys/posix"
 
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Added Odin Helpers ------------------------
+// ---------------------------------------------------------------------------------------------------------------------
+
+// Wrap a blittable value's bytes as an LMDB Val.
+// T must be a contiguous type with no indirection (no pointers, slices, strings, maps, etc.).
+blittable_val :: #force_inline proc(val_ptr: ^$T) -> Val {
+	fmt.assertf(
+		reflect.has_no_indirections(type_info_of(T)),
+		"blitval: type '%v' contains indirection and cannot be stored directly in LMDB",
+		typeid_of(T),
+	)
+	return Val{size_of(T), val_ptr}
+}
+
+// Reads a blittable T out of the LMDB memory map by copying it into caller
+// storage. The returned T has no lifetime tie to the transaction.
+blittable_copy :: #force_inline proc(val: ^Val, $T: typeid) -> T {
+	fmt.assertf(
+		reflect.has_no_indirections(type_info_of(T)),
+		"blitval_copy: type '%v' contains indirection and cannot be read directly from LMDB",
+		typeid_of(T),
+	)
+	return (cast(^T)val.data)^
+}
+
+// Zero-copy pointer view into the LMDB memory map as a ^T.
+// Useful for large blittable types where you want to read individual fields
+// without copying the entire value (e.g. ptr.timestamp, ptr.flags).
+// MUST NOT be written through — writes either segfault (default env mode)
+// or silently corrupt the database (ENV_WRITEMAP).
+// MUST NOT be retained past txn_commit, txn_abort, or any subsequent write
+// operation on the same env — the pointer is invalidated.
+blittable_view :: #force_inline proc(val: ^Val, $T: typeid) -> ^T {
+	fmt.assertf(
+		reflect.has_no_indirections(type_info_of(T)),
+		"blitval_view: type '%v' contains indirection and cannot be viewed directly from LMDB",
+		typeid_of(T),
+	)
+	return cast(^T)val.data
+}
+
+// Wrap a slice of blittable elements as an LMDB Val for use with put/get.
+// T must be a contiguous type with no indirection.
+// The caller's slice must remain valid (not freed, not resized) for the
+// duration of the put call that consumes this Val.
+slice_val :: #force_inline proc(s: []$T) -> Val {
+	fmt.assertf(
+		reflect.has_no_indirections(type_info_of(T)),
+		"slice_val: element type '%v' contains indirection and cannot be stored directly in LMDB",
+		typeid_of(T),
+	)
+	return Val{uint(len(s) * size_of(T)), raw_data(s)}
+}
+
+// Zero-copy slice view into the LMDB memory map.
+// T must match the element type that was originally stored.
+// MUST NOT be modified — writes through this slice either segfault (default
+// env mode) or silently corrupt the database (ENV_WRITEMAP).
+// MUST be copied (e.g. slice.clone) if it needs to outlive the current
+// transaction; the view is invalidated by txn_commit, txn_abort, or any
+// subsequent write operation on the same env.
+slice_view :: #force_inline proc(val: ^Val, $T: typeid) -> []T {
+	fmt.assertf(
+		reflect.has_no_indirections(type_info_of(T)),
+		"slice_view: element type '%v' contains indirection and cannot be read directly from LMDB",
+		typeid_of(T),
+	)
+	return (cast([^]T)val.data)[:val.size / size_of(T)]
+}
+
+// Wrap a string's bytes as an LMDB Val for use with put/get.
+// The caller's string must remain valid (backing memory not freed) for the
+// duration of the put call that consumes this Val.
+string_val :: #force_inline proc(s: string) -> Val {
+	return Val{uint(len(s)), raw_data(s)}
+}
+
+// Zero-copy string view into the LMDB memory map.
+// MUST NOT be modified — writes through the underlying bytes either segfault
+// (default env mode) or silently corrupt the database (ENV_WRITEMAP).
+// MUST be copied (e.g. strings.clone) if it needs to outlive the current
+// transaction; the view is invalidated by txn_commit, txn_abort, or any
+// subsequent write operation on the same env.
+string_view :: #force_inline proc(val: ^Val) -> string {
+	return string((cast([^]u8)val.data)[:val.size])
+}
+
+// Panic if there is an error
+panic_on_err :: #force_inline proc(error: Error, loc := #caller_location) {
+	if error != .NONE {
+		fmt.panicf("LMDB error %v: %s", error, strerror(i32(error)), loc = loc)
+	}
+}
+
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Bindings ------------------------
+// ---------------------------------------------------------------------------------------------------------------------
+
 _ :: c
 
 when ODIN_OS == .Windows {
+	#panic("TODO: Compile windows .lib for lmdb")
 	mode_t :: c.int
-} else {
-	mode_t :: posix.mode_t
-}
-
-when ODIN_OS == .Windows {
 	filehandle_t :: rawptr
-} else {
+} else when ODIN_OS ==
+	.Linux || ODIN_OS == .Darwin || ODIN_OS == .FreeBSD || ODIN_OS == .OpenBSD || ODIN_OS == .NetBSD {
+	foreign import lib "system:lmdb"
+	mode_t :: posix.mode_t
 	filehandle_t :: c.int
+} else {
+	#panic("levlib/vendor/lmdb: unsupported OS target")
 }
 
 Env :: struct {}
@@ -189,7 +288,7 @@ Env :: struct {}
 Txn :: struct {}
 
 /** @brief A handle for an individual database in the DB environment. */
-Dbi :: u32
+Dbi :: c.uint
 
 Cursor :: struct {}
 
@@ -205,33 +304,8 @@ Cursor :: struct {}
 * Other data items can in theory be from 0 to 0xffffffff bytes long.
 */
 Val :: struct {
-	mv_size: uint, /**< size of the data item */
-	mv_data: rawptr, /**< address of the data item */
-}
-
-// Automatic `Val` handling for a given type 'T'.
-// Will not traverse pointers. If `T` stores pointers, you probably don't want to use this.
-Auto_Val :: struct($T: typeid) {
-	raw: Val,
-}
-
-autoval :: #force_inline proc "contextless" (val_ptr: ^$T) -> Auto_Val(T) {
-	return Auto_Val(T){Val{size_of(T), val_ptr}}
-}
-
-nil_autoval :: #force_inline proc "contextless" ($T: typeid) -> Auto_Val(T) {
-	return Auto_Val(T){Val{size_of(T), nil}}
-}
-
-autoval_get_data :: #force_inline proc "contextless" (val: ^Auto_Val($T)) -> ^T {
-	return cast(^T)val.raw.mv_data
-}
-
-// Panic if there is an error
-panic_on_err :: #force_inline proc(error: Error) {
-	if error != .NONE {
-		fmt.panicf("Irrecoverable LMDB error", strerror(i32(error)))
-	}
+	size: uint, /**< size of the data item */
+	data: rawptr, /**< address of the data item */
 }
 
 /** @brief A callback function used to compare two keys in a database */
@@ -253,85 +327,65 @@ Cmp_Func :: #type proc "c" (_: ^Val, _: ^Val) -> i32
 */
 Rel_Func :: #type proc "c" (item: ^Val, oldptr, newptr, relctx: rawptr)
 
-/** @defgroup	mdb_env	Environment Flags
+/** @defgroup mdb_env Environment Flags
  *	@{
  */
-/** mmap at a fixed address (experimental) */
-ENV_FIXEDMAP :: 0x01
-/** no environment directory */
-ENV_NOSUBDIR :: 0x4000
-/** don't fsync after commit */
-ENV_NOSYNC :: 0x10000
-/** read only */
-ENV_RDONLY :: 0x20000
-/** don't fsync metapage after commit */
-ENV_NOMETASYNC :: 0x40000
-/** use writable mmap */
-ENV_WRITEMAP :: 0x80000
-/** use asynchronous msync when #MDB_WRITEMAP is used */
-ENV_MAPASYNC :: 0x100000
-/** tie reader locktable slots to #MDB_txn objects instead of to threads */
-ENV_NOTLS :: 0x200000
-/** don't do any locking, caller must manage their own locks */
-ENV_NOLOCK :: 0x400000
-/** don't do readahead (no effect on Windows) */
-ENV_NORDAHEAD :: 0x800000
-/** don't initialize malloc'd memory before writing to datafile */
-ENV_NOMEMINIT :: 0x1000000
+Env_Flag :: enum u32 {
+	FIXEDMAP     = 0, /**< mmap at a fixed address (experimental) */
+	NOSUBDIR     = 14, /**< no environment directory */
+	NOSYNC       = 16, /**< don't fsync after commit */
+	RDONLY       = 17, /**< read only */
+	NOMETASYNC   = 18, /**< don't fsync metapage after commit */
+	WRITEMAP     = 19, /**< use writable mmap */
+	MAPASYNC     = 20, /**< use asynchronous msync when WRITEMAP is used */
+	NOTLS        = 21, /**< tie reader locktable slots to Txn objects instead of to threads */
+	NOLOCK       = 22, /**< don't do any locking, caller must manage their own locks */
+	NORDAHEAD    = 23, /**< don't do readahead (no effect on Windows) */
+	NOMEMINIT    = 24, /**< don't initialize malloc'd memory before writing to datafile */
+	PREVSNAPSHOT = 25, /**< use the previous snapshot rather than the latest one */
+}
+Env_Flags :: distinct bit_set[Env_Flag;c.uint]
 /** @} */
 
-/**	@defgroup	mdb_dbi_open	Database Flags
+/** @defgroup mdb_dbi_open Database Flags
  *	@{
  */
-/** use reverse string keys */
-DB_REVERSEKEY :: 0x02
-/** use sorted duplicates */
-DB_DUPSORT :: 0x04
-/** numeric keys in native byte order: either unsigned int or size_t.
-	 *  The keys must all be of the same size. */
-DB_INTEGERKEY :: 0x08
-/** with #MDB_DUPSORT, sorted dup items have fixed size */
-DB_DUPFIXED :: 0x10
-/** with #MDB_DUPSORT, dups are #MDB_INTEGERKEY-style integers */
-DB_INTEGERDUP :: 0x20
-/** with #MDB_DUPSORT, use reverse string dups */
-DB_REVERSEDUP :: 0x40
-/** create DB if not already existing */
-DB_CREATE :: 0x40000
+Db_Flag :: enum u32 {
+	REVERSEKEY = 1, /**< use reverse string keys */
+	DUPSORT    = 2, /**< use sorted duplicates */
+	INTEGERKEY = 3, /**< numeric keys in native byte order */
+	DUPFIXED   = 4, /**< with DUPSORT, sorted dup items have fixed size */
+	INTEGERDUP = 5, /**< with DUPSORT, dups are INTEGERKEY-style integers */
+	REVERSEDUP = 6, /**< with DUPSORT, use reverse string dups */
+	CREATE     = 18, /**< create DB if not already existing */
+}
+Db_Flags :: distinct bit_set[Db_Flag;c.uint]
 /** @} */
 
-/**	@defgroup mdb_put	Write Flags
+/** @defgroup mdb_put Write Flags
  *	@{
  */
-/** For put: Don't write if the key already exists. */
-WRITE_NOOVERWRITE :: 0x10
-/** Only for #MDB_DUPSORT<br>
- * For put: don't write if the key and data pair already exist.<br>
- * For mdb_cursor_del: remove all duplicate data items.
- */
-WRITE_NODUPDATA :: 0x20
-/** For mdb_cursor_put: overwrite the current key/data pair */
-WRITE_CURRENT :: 0x40
-/** For put: Just reserve space for data, don't copy it. Return a
- * pointer to the reserved space.
- */
-WRITE_RESERVE :: 0x10000
-/** Data is being appended, don't split full pages. */
-WRITE_APPEND :: 0x20000
-/** Duplicate data is being appended, don't split full pages. */
-WRITE_APPENDDUP :: 0x40000
-/** Store multiple data items in one call. Only for #MDB_DUPFIXED. */
-WRITE_MULTIPLE :: 0x80000
-/*	@} */
+Write_Flag :: enum u32 {
+	NOOVERWRITE = 4, /**< For put: Don't write if the key already exists */
+	NODUPDATA   = 5, /**< For DUPSORT: don't write if the key and data pair already exist.
+	                       For mdb_cursor_del: remove all duplicate data items. */
+	CURRENT     = 6, /**< For mdb_cursor_put: overwrite the current key/data pair */
+	RESERVE     = 16, /**< For put: Just reserve space for data, don't copy it */
+	APPEND      = 17, /**< Data is being appended, don't split full pages */
+	APPENDDUP   = 18, /**< Duplicate data is being appended, don't split full pages */
+	MULTIPLE    = 19, /**< Store multiple data items in one call. Only for DUPFIXED. */
+}
+Write_Flags :: distinct bit_set[Write_Flag;c.uint]
+/** @} */
 
-/**	@defgroup mdb_copy	Copy Flags
+/** @defgroup mdb_copy Copy Flags
  *	@{
  */
-/** Compacting copy: Omit free space from copy, and renumber all
- * pages sequentially.
- */
-CP_COMPACT :: 0x01
-/*	@} */
+Copy_Flag :: enum u32 {
+	COMPACT = 0, /**< Compacting copy: Omit free space from copy, and renumber all pages sequentially. */
+}
+Copy_Flags :: distinct bit_set[Copy_Flag;c.uint]
+/** @} */
 
 /** @brief Cursor Get operations.
 *
@@ -340,33 +394,24 @@ CP_COMPACT :: 0x01
 */
 Cursor_Op :: enum c.int {
 	FIRST, /**< Position at first key/data item */
-	FIRST_DUP, /**< Position at first data item of current key.
-								Only for #MDB_DUPSORT */
-	GET_BOTH, /**< Position at key/data pair. Only for #MDB_DUPSORT */
-	GET_BOTH_RANGE, /**< position at key, nearest data. Only for #MDB_DUPSORT */
+	FIRST_DUP, /**< Position at first data item of current key. Only for DUPSORT */
+	GET_BOTH, /**< Position at key/data pair. Only for DUPSORT */
+	GET_BOTH_RANGE, /**< Position at key, nearest data. Only for DUPSORT */
 	GET_CURRENT, /**< Return key/data at current cursor position */
-	GET_MULTIPLE, /**< Return up to a page of duplicate data items
-								from current cursor position. Move cursor to prepare
-								for #MDB_NEXT_MULTIPLE. Only for #MDB_DUPFIXED */
+	GET_MULTIPLE, /**< Return up to a page of duplicate data items from current cursor position. Only for DUPFIXED */
 	LAST, /**< Position at last key/data item */
-	LAST_DUP, /**< Position at last data item of current key.
-								Only for #MDB_DUPSORT */
+	LAST_DUP, /**< Position at last data item of current key. Only for DUPSORT */
 	NEXT, /**< Position at next data item */
-	NEXT_DUP, /**< Position at next data item of current key.
-								Only for #MDB_DUPSORT */
-	NEXT_MULTIPLE, /**< Return up to a page of duplicate data items
-								from next cursor position. Move cursor to prepare
-								for #MDB_NEXT_MULTIPLE. Only for #MDB_DUPFIXED */
+	NEXT_DUP, /**< Position at next data item of current key. Only for DUPSORT */
+	NEXT_MULTIPLE, /**< Return up to a page of duplicate data items from next cursor position. Only for DUPFIXED */
 	NEXT_NODUP, /**< Position at first data item of next key */
 	PREV, /**< Position at previous data item */
-	PREV_DUP, /**< Position at previous data item of current key.
-								Only for #MDB_DUPSORT */
+	PREV_DUP, /**< Position at previous data item of current key. Only for DUPSORT */
 	PREV_NODUP, /**< Position at last data item of previous key */
 	SET, /**< Position at specified key */
 	SET_KEY, /**< Position at specified key, return key + data */
-	SET_RANGE, /**< Position at first key greater than or equal to specified key. */
-	PREV_MULTIPLE, /**< Position at previous page and return up to
-								a page of duplicate data items. Only for #MDB_DUPFIXED */
+	SET_RANGE, /**< Position at first key greater than or equal to specified key */
+	PREV_MULTIPLE, /**< Position at previous page and return up to a page of duplicate data items. Only for DUPFIXED */
 }
 
 Error :: enum c.int {
@@ -419,33 +464,28 @@ Error :: enum c.int {
 	BAD_VALSIZE      = -30781,
 	/** The specified DBI was changed unexpectedly */
 	BAD_DBI          = -30780,
+	/** Unexpected problem - txn should abort */
+	PROBLEM          = -30779,
 }
 
 /** @brief Statistics for a database in the environment */
 Stat :: struct {
-	ms_psize:          u32,
-	/**< Size of a database page.
-											This is currently the same for all databases. */
-	ms_depth:          u32,
-	/**< Depth (height) of the B-tree */
-	ms_branch_pages:   uint,
-	/**< Number of internal (non-leaf) pages */
-	ms_leaf_pages:     uint,
-	/**< Number of leaf pages */
-	ms_overflow_pages: uint,
-	/**< Number of overflow pages */
-	ms_entries:        uint,
-	/**< Number of data items */
+	psize:          u32, /**< Size of a database page. This is currently the same for all databases. */
+	depth:          u32, /**< Depth (height) of the B-tree */
+	branch_pages:   uint, /**< Number of internal (non-leaf) pages */
+	leaf_pages:     uint, /**< Number of leaf pages */
+	overflow_pages: uint, /**< Number of overflow pages */
+	entries:        uint, /**< Number of data items */
 }
 
 /** @brief Information about the environment */
 Env_Info :: struct {
-	me_mapaddr:    rawptr, /**< Address of map, if fixed */
-	me_mapsize:    uint, /**< Size of the data memory map */
-	me_last_pgno:  uint, /**< ID of the last used page */
-	me_last_txnid: uint, /**< ID of the last committed transaction */
-	me_maxreaders: u32, /**< max reader slots in the environment */
-	me_numreaders: u32, /**< max reader slots used in the environment */
+	mapaddr:    rawptr, /**< Address of map, if fixed */
+	mapsize:    uint, /**< Size of the data memory map */
+	last_pgno:  uint, /**< ID of the last used page */
+	last_txnid: uint, /**< ID of the last committed transaction */
+	maxreaders: u32, /**< max reader slots in the environment */
+	numreaders: u32, /**< max reader slots used in the environment */
 }
 
 /** @brief A callback function for most LMDB assert() failures,
@@ -454,7 +494,7 @@ Env_Info :: struct {
 * @param[in] env An environment handle returned by #mdb_env_create().
 * @param[in] msg The assertion message, not including newline.
 */
-Assert_Func :: proc "c" (_: ^Env, _: cstring)
+Assert_Func :: #type proc "c" (_: ^Env, _: cstring)
 
 /** @brief A callback function used to print a message from the library.
 *
@@ -462,7 +502,7 @@ Assert_Func :: proc "c" (_: ^Env, _: cstring)
 * @param[in] ctx An arbitrary context pointer for the callback.
 * @return < 0 on failure, >= 0 on success.
 */
-Msg_Func :: proc "c" (_: cstring, _: rawptr) -> i32
+Msg_Func :: #type proc "c" (_: cstring, _: rawptr) -> i32
 
 @(default_calling_convention = "c", link_prefix = "mdb_")
 foreign lib {
@@ -623,7 +663,7 @@ foreign lib {
 	* </ul>
 	*/
 	@(require_results)
-	env_open :: proc(env: ^Env, path: cstring, flags: u32, mode: mode_t) -> Error ---
+	env_open :: proc(env: ^Env, path: cstring, flags: Env_Flags, mode: mode_t) -> Error ---
 
 	/** @brief Copy an LMDB environment to the specified path.
 	*
@@ -682,7 +722,7 @@ foreign lib {
 	* @return A non-zero error value on failure and 0 on success.
 	*/
 	@(require_results)
-	env_copy2 :: proc(env: ^Env, path: cstring, flags: u32) -> Error ---
+	env_copy2 :: proc(env: ^Env, path: cstring, flags: Copy_Flags) -> Error ---
 
 	/** @brief Copy an LMDB environment to the specified file descriptor,
 	*	with options.
@@ -702,7 +742,7 @@ foreign lib {
 	* @return A non-zero error value on failure and 0 on success.
 	*/
 	@(require_results)
-	env_copyfd2 :: proc(env: ^Env, fd: filehandle_t, flags: u32) -> Error ---
+	env_copyfd2 :: proc(env: ^Env, fd: filehandle_t, flags: Copy_Flags) -> Error ---
 
 	/** @brief Return statistics about the LMDB environment.
 	*
@@ -767,7 +807,7 @@ foreign lib {
 	* </ul>
 	*/
 	@(require_results)
-	env_set_flags :: proc(env: ^Env, flags: u32, onoff: i32) -> Error ---
+	env_set_flags :: proc(env: ^Env, flags: Env_Flags, onoff: i32) -> Error ---
 
 	/** @brief Get environment flags.
 	*
@@ -780,7 +820,7 @@ foreign lib {
 	* </ul>
 	*/
 	@(require_results)
-	env_get_flags :: proc(env: ^Env, flags: ^u32) -> Error ---
+	env_get_flags :: proc(env: ^Env, flags: ^Env_Flags) -> Error ---
 
 	/** @brief Return the path that was used in #mdb_env_open().
 	*
@@ -973,7 +1013,7 @@ foreign lib {
 	* </ul>
 	*/
 	@(require_results)
-	txn_begin :: proc(env: ^Env, parent: ^Txn, flags: u32, txn: ^^Txn) -> Error ---
+	txn_begin :: proc(env: ^Env, parent: ^Txn, flags: Env_Flags, txn: ^^Txn) -> Error ---
 
 	/** @brief Returns the transaction's #MDB_env
 	*
@@ -1126,7 +1166,7 @@ foreign lib {
 	* </ul>
 	*/
 	@(require_results)
-	dbi_open :: proc(txn: ^Txn, name: cstring, flags: u32, dbi: ^Dbi) -> Error ---
+	dbi_open :: proc(txn: ^Txn, name: cstring, flags: Db_Flags, dbi: ^Dbi) -> Error ---
 
 	/** @brief Retrieve statistics for a database.
 	*
@@ -1151,7 +1191,7 @@ foreign lib {
 	* @return A non-zero error value on failure and 0 on success.
 	*/
 	@(require_results)
-	dbi_flags :: proc(txn: ^Txn, dbi: Dbi, flags: ^u32) -> Error ---
+	dbi_flags :: proc(txn: ^Txn, dbi: Dbi, flags: ^Db_Flags) -> Error ---
 
 	/** @brief Close a database handle. Normally unnecessary. Use with care:
 	*
@@ -1229,6 +1269,7 @@ foreign lib {
 	@(require_results)
 	set_dupsort :: proc(txn: ^Txn, dbi: Dbi, cmp: Cmp_Func) -> Error ---
 
+	// NOTE: Unimplemented in current LMDB — this function has no effect.
 	/** @brief Set a relocation function for a #MDB_FIXEDMAP database.
 	*
 	* @todo The relocation function is called whenever it is necessary to move the data
@@ -1250,6 +1291,7 @@ foreign lib {
 	@(require_results)
 	set_relfunc :: proc(txn: ^Txn, dbi: Dbi, rel: Rel_Func) -> Error ---
 
+	// NOTE: Unimplemented in current LMDB — this function has no effect.
 	/** @brief Set a context pointer for a #MDB_FIXEDMAP database's relocation function.
 	*
 	* See #mdb_set_relfunc and #MDB_rel_func for more details.
@@ -1344,7 +1386,7 @@ foreign lib {
 	* </ul>
 	*/
 	@(require_results)
-	put :: proc(txn: ^Txn, dbi: Dbi, key: ^Val, data: ^Val, flags: u32) -> Error ---
+	put :: proc(txn: ^Txn, dbi: Dbi, key: ^Val, data: ^Val, flags: Write_Flags) -> Error ---
 
 	/** @brief Delete items from a database.
 	*
@@ -1517,7 +1559,7 @@ foreign lib {
 	* </ul>
 	*/
 	@(require_results)
-	cursor_put :: proc(cursor: ^Cursor, key: ^Val, data: ^Val, flags: u32) -> Error ---
+	cursor_put :: proc(cursor: ^Cursor, key: ^Val, data: ^Val, flags: Write_Flags) -> Error ---
 
 	/** @brief Delete current key/data pair
 	*
@@ -1541,7 +1583,7 @@ foreign lib {
 	* </ul>
 	*/
 	@(require_results)
-	cursor_del :: proc(cursor: ^Cursor, flags: u32) -> Error ---
+	cursor_del :: proc(cursor: ^Cursor, flags: Write_Flags) -> Error ---
 
 	/** @brief Return count of duplicates for current key.
 	*