fix(examples): macOS outline post-FX + missing Color export (#48)

Two unrelated bugs surfaced together when @adevart tried the example
projects on macOS:

1. `outline_bg` bind group failed validation on Apple GPUs because the
   R32Float object-ID texture was declared `Float { filterable: true }`,
   which requires the FLOAT32_FILTERABLE wgpu feature (not advertised by
   Metal). Switch the binding to `filterable: false` and use textureLoad
   instead of textureSample for the ID lookup — semantically correct
   anyway, since IDs should never be interpolated.

2. The `export { ColorConstants as Color } from './colors'` rename in
   src/core/index.ts produced no Perry FFI symbol for `Color`, so any
   example importing `Color` from `bloom/core` (pong, dungeon-crawl,
   kart-racer, isometric-rpg, space-blaster, voxel-sandbox) failed to
   link with `Undefined symbol _perry_fn_src_core_colors_ts__Color`.
   Make `Color` a real top-level binding in colors.ts and keep
   `ColorConstants` as an aliased export.

Author: proggeramlug

native/shared/src/postfx.rs

@@ -51,18 +51,24 @@ struct VertexOutput {
 @fragment
 fn fs_outline(in: VertexOutput) -> @location(0) vec4<f32> {
     let color = textureSample(scene_color, tex_sampler, in.uv);
-    let center_id = textureSample(object_id_tex, tex_sampler, in.uv).r;
 
-    let pixel = vec2<f32>(1.0 / params.screen_size.x, 1.0 / params.screen_size.y);
-    let t = params.thickness.x;
+    // Object IDs must not be filtered — interpolating IDs produces nonsense
+    // values at edges. Use textureLoad with integer coords; this also avoids
+    // requiring the FLOAT32_FILTERABLE wgpu feature (not advertised on Apple GPUs).
+    let dim = vec2<i32>(textureDimensions(object_id_tex));
+    let max_xy = dim - vec2<i32>(1, 1);
+    let center_pix = clamp(vec2<i32>(in.uv * vec2<f32>(dim)), vec2<i32>(0, 0), max_xy);
+    let center_id = textureLoad(object_id_tex, center_pix, 0).r;
+
+    let t = max(1, i32(round(params.thickness.x)));
 
     // Sample neighbors for edge detection
     var edge = 0.0;
     for (var dy = -1; dy <= 1; dy++) {
         for (var dx = -1; dx <= 1; dx++) {
             if (dx == 0 && dy == 0) { continue; }
-            let offset = vec2<f32>(f32(dx), f32(dy)) * pixel * t;
-            let neighbor_id = textureSample(object_id_tex, tex_sampler, in.uv + offset).r;
+            let neighbor_pix = clamp(center_pix + vec2<i32>(dx, dy) * t, vec2<i32>(0, 0), max_xy);
+            let neighbor_id = textureLoad(object_id_tex, neighbor_pix, 0).r;
             if (abs(neighbor_id - center_id) > 0.001) {
                 edge += 1.0;
             }
@@ -169,7 +175,9 @@ impl PostFxPipeline {
             label: Some("outline_bg_layout"),
             entries: &[
                 bgl_texture(0, wgpu::TextureSampleType::Float { filterable: true }),
-                bgl_texture(1, wgpu::TextureSampleType::Float { filterable: true }),
+                // R32Float — non-filterable on adapters without FLOAT32_FILTERABLE
+                // (e.g. Apple GPUs). Sampled via textureLoad in OUTLINE_FRAG.
+                bgl_texture(1, wgpu::TextureSampleType::Float { filterable: false }),
                 bgl_sampler(2),
                 bgl_uniform(3),
             ],

src/core/colors.ts

@@ -1,6 +1,10 @@
-import { Color } from './types';
+import { Color as ColorType } from './types';
 
-export const ColorConstants: Record<string, Color> = {
+// Canonical color palette. Re-exported as `Color` from `bloom/core` and
+// declared as a real top-level binding (not an alias re-export) so Perry
+// emits a `_perry_fn_src_core_colors_ts__Color` symbol that examples
+// importing `Color` from `bloom/core` can link against.
+export const Color: Record<string, ColorType> = {
   RayWhite:   { r: 245, g: 245, b: 245, a: 255 },
   White:      { r: 255, g: 255, b: 255, a: 255 },
   Black:      { r: 0,   g: 0,   b: 0,   a: 255 },
@@ -27,30 +31,33 @@ export const ColorConstants: Record<string, Color> = {
   Blank:      { r: 0,   g: 0,   b: 0,   a: 0   },
 };
 
+// Backward-compatible alias — same object, kept for older imports.
+export const ColorConstants = Color;
+
 // Backward-compatible alias with SCREAMING_SNAKE keys
-export const Colors: Record<string, Color> = {
-  WHITE:      ColorConstants.White,
-  BLACK:      ColorConstants.Black,
-  RED:        ColorConstants.Red,
-  GREEN:      ColorConstants.Green,
-  BLUE:       ColorConstants.Blue,
-  YELLOW:     ColorConstants.Yellow,
-  ORANGE:     ColorConstants.Orange,
-  PINK:       ColorConstants.Pink,
-  PURPLE:     ColorConstants.Purple,
-  DARKGRAY:   ColorConstants.DarkGray,
-  LIGHTGRAY:  ColorConstants.LightGray,
-  GRAY:       ColorConstants.Gray,
-  DARKBLUE:   ColorConstants.DarkBlue,
-  SKYBLUE:    ColorConstants.SkyBlue,
-  LIME:       ColorConstants.Lime,
-  DARKGREEN:  ColorConstants.DarkGreen,
-  GOLD:       ColorConstants.Gold,
-  MAROON:     ColorConstants.Maroon,
-  BROWN:      ColorConstants.Brown,
-  BEIGE:      ColorConstants.Beige,
-  MAGENTA:    ColorConstants.Magenta,
-  VIOLET:     ColorConstants.Violet,
-  RAYWHITE:   ColorConstants.RayWhite,
-  BLANK:      ColorConstants.Blank,
+export const Colors: Record<string, ColorType> = {
+  WHITE:      Color.White,
+  BLACK:      Color.Black,
+  RED:        Color.Red,
+  GREEN:      Color.Green,
+  BLUE:       Color.Blue,
+  YELLOW:     Color.Yellow,
+  ORANGE:     Color.Orange,
+  PINK:       Color.Pink,
+  PURPLE:     Color.Purple,
+  DARKGRAY:   Color.DarkGray,
+  LIGHTGRAY:  Color.LightGray,
+  GRAY:       Color.Gray,
+  DARKBLUE:   Color.DarkBlue,
+  SKYBLUE:    Color.SkyBlue,
+  LIME:       Color.Lime,
+  DARKGREEN:  Color.DarkGreen,
+  GOLD:       Color.Gold,
+  MAROON:     Color.Maroon,
+  BROWN:      Color.Brown,
+  BEIGE:      Color.Beige,
+  MAGENTA:    Color.Magenta,
+  VIOLET:     Color.Violet,
+  RAYWHITE:   Color.RayWhite,
+  BLANK:      Color.Blank,
 };

src/core/index.ts

@@ -1,8 +1,7 @@
 import { Color, Camera2D, Camera3D } from './types';
 
 export type { Color, Vec2, Vec3, Vec4, Rect, Camera2D, Camera3D, Texture, Font, Sound, Music, Quat, Ray, BoundingBox, Model, Mat4, RayHit, FrustumPlanes } from './types';
-export { ColorConstants, Colors } from './colors';
-export { ColorConstants as Color } from './colors';
+export { Color, ColorConstants, Colors } from './colors';
 export { Key, MouseButton } from './keys';
 
 // FFI declarations