DPI scaling fixes

draw/shaders/source/base_2d.vert

@@ -1,6 +1,6 @@
 #version 450 core
 
-// ---------- Vertex attributes (used in both modes) ----------
+// ---------- Vertex attributes (used in all modes) ----------
 layout(location = 0) in vec2 v_position;
 layout(location = 1) in vec2 v_uv;
 layout(location = 2) in vec4 v_color;
@@ -16,10 +16,18 @@ layout(location = 6) flat out vec4 f_uv_rect;
 layout(location = 7) flat out uvec4 f_effects;
 
 // ---------- Uniforms (single block — avoids spirv-cross reordering on Metal) ----------
+// Mode values mirror Core_2D_Mode in core_2d.odin:
+//   0 = Tessellated  v_position is in logical pixels; shader scales by dpi_scale.
+//   1 = SDF          v_position is a unit-quad corner; world-space comes from
+//                    primitives[gl_InstanceIndex].bounds (logical px). Shader
+//                    scales by dpi_scale.
+//   2 = Text         v_position is in *physical* pixels already (the CPU baked
+//                    the anchor snap and SDL_ttf glyph offsets, both physical).
+//                    Shader must NOT rescale.
 layout(set = 1, binding = 0) uniform Uniforms {
     mat4 projection;
     float dpi_scale;
-    uint mode; // 0 = tessellated, 1 = SDF
+    uint mode;
 };
 
 // ---------- SDF primitive storage buffer ----------
@@ -44,18 +52,7 @@ layout(std430, set = 0, binding = 0) readonly buffer Core_2D_Primitives {
 
 // ---------- Entry point ----------
 void main() {
-    if (mode == 0u) {
-        // ---- Mode 0: Tessellated (used for text and arbitrary user geometry) ----
-        f_color = v_color;
-        f_local_or_uv = v_uv;
-        f_params = vec4(0.0);
-        f_params2 = vec4(0.0);
-        f_flags = 0u;
-        f_uv_rect = vec4(0.0);
-        f_effects = uvec4(0);
-
-        gl_Position = projection * vec4(v_position * dpi_scale, 0.0, 1.0);
-    } else {
+    if (mode == 1u) {
         // ---- Mode 1: SDF instanced quads ----
         Core_2D_Primitive p = primitives[gl_InstanceIndex];
 
@@ -86,5 +83,25 @@ void main() {
         f_effects = p.effects;
 
         gl_Position = projection * vec4(world_pos * dpi_scale, 0.0, 1.0);
+    } else {
+        // ---- Mode 0 (Tessellated) and Mode 2 (Text) ----
+        // Both feed the raw-vertex pipeline (kind 0 in the fragment shader).
+        // They differ only in what coord space `v_position` is in:
+        //   Mode 0 — logical pixels, scale here by dpi_scale.
+        //   Mode 2 — physical pixels (CPU pre-scaled and snapped to integer
+        //            physical pixels for atlas-aligned bilinear sampling).
+        //            Do NOT rescale.
+        // `mode` is uniform across the workgroup, so the select compiles to a
+        // uniform-controlled branch with no SIMT divergence cost.
+        f_color = v_color;
+        f_local_or_uv = v_uv;
+        f_params = vec4(0.0);
+        f_params2 = vec4(0.0);
+        f_flags = 0u;
+        f_uv_rect = vec4(0.0);
+        f_effects = uvec4(0);
+
+        vec2 pos = (mode == 2u) ? v_position : (v_position * dpi_scale);
+        gl_Position = projection * vec4(pos, 0.0, 1.0);
     }
 }