refactor(effects): co-locate effect WGSL shaders with their .h/.cc in src/effects/

Move 13 effect-specific shaders from workspaces/main/shaders/ to src/effects/
so each effect's .h, .cc, and .wgsl are together. Update assets.txt paths in
both main and test workspaces. Update EFFECT_WORKFLOW.md to reflect new location.
Shared/reusable snippets remain in src/shaders/.

handoff(Gemini): shaders moved; src/effects/ now has .h, .cc, and .wgsl per effect.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 89 insertions, 0 deletions

diff --git a/src/effects/rotating_cube.wgsl b/src/effects/rotating_cube.wgsl
new file mode 100644
index 0000000..0c75a13
--- /dev/null
+++ b/src/effects/rotating_cube.wgsl
@@ -0,0 +1,89 @@
+// Rotating cube shader v2 (simplified, no masking)
+
+struct Uniforms {
+    view_proj: mat4x4f,
+    inv_view_proj: mat4x4f,
+    camera_pos_time: vec4f,
+    params: vec4f,
+    resolution: vec2f,
+    aspect_ratio: f32,
+    _pad: f32,
+};
+
+struct ObjectData {
+    model: mat4x4f,
+    inv_model: mat4x4f,
+    color: vec4f,
+    params: vec4f,
+};
+
+@group(0) @binding(0) var<uniform> uniforms: Uniforms;
+@group(0) @binding(1) var<storage, read> object: ObjectData;
+
+struct VSOut {
+    @builtin(position) pos: vec4f,
+    @location(0) world_pos: vec3f,
+    @location(1) normal: vec3f,
+};
+
+// Cube vertices (hardcoded)
+fn get_cube_vertex(vid: u32) -> vec3f {
+    let positions = array<vec3f, 36>(
+        // Front face
+        vec3f(-1, -1,  1), vec3f( 1, -1,  1), vec3f( 1,  1,  1),
+        vec3f(-1, -1,  1), vec3f( 1,  1,  1), vec3f(-1,  1,  1),
+        // Back face
+        vec3f( 1, -1, -1), vec3f(-1, -1, -1), vec3f(-1,  1, -1),
+        vec3f( 1, -1, -1), vec3f(-1,  1, -1), vec3f( 1,  1, -1),
+        // Right face
+        vec3f( 1, -1,  1), vec3f( 1, -1, -1), vec3f( 1,  1, -1),
+        vec3f( 1, -1,  1), vec3f( 1,  1, -1), vec3f( 1,  1,  1),
+        // Left face
+        vec3f(-1, -1, -1), vec3f(-1, -1,  1), vec3f(-1,  1,  1),
+        vec3f(-1, -1, -1), vec3f(-1,  1,  1), vec3f(-1,  1, -1),
+        // Top face
+        vec3f(-1,  1,  1), vec3f( 1,  1,  1), vec3f( 1,  1, -1),
+        vec3f(-1,  1,  1), vec3f( 1,  1, -1), vec3f(-1,  1, -1),
+        // Bottom face
+        vec3f(-1, -1, -1), vec3f( 1, -1, -1), vec3f( 1, -1,  1),
+        vec3f(-1, -1, -1), vec3f( 1, -1,  1), vec3f(-1, -1,  1)
+    );
+    return positions[vid];
+}
+
+fn get_cube_normal(vid: u32) -> vec3f {
+    let face_id = vid / 6u;
+    let normals = array<vec3f, 6>(
+        vec3f( 0,  0,  1),  // Front
+        vec3f( 0,  0, -1),  // Back
+        vec3f( 1,  0,  0),  // Right
+        vec3f(-1,  0,  0),  // Left
+        vec3f( 0,  1,  0),  // Top
+        vec3f( 0, -1,  0)   // Bottom
+    );
+    return normals[face_id];
+}
+
+@vertex fn vs_main(@builtin(vertex_index) vid: u32) -> VSOut {
+    let local_pos = get_cube_vertex(vid);
+    let local_normal = get_cube_normal(vid);
+
+    let world_pos = object.model * vec4f(local_pos, 1.0);
+    let world_normal = normalize((object.model * vec4f(local_normal, 0.0)).xyz);
+
+    let clip_pos = uniforms.view_proj * world_pos;
+
+    return VSOut(clip_pos, world_pos.xyz, world_normal);
+}
+
+@fragment fn fs_main(@location(0) world_pos: vec3f, @location(1) normal: vec3f) -> @location(0) vec4f {
+    let N = normalize(normal);
+    let light_dir = normalize(vec3f(1.0, 1.0, 1.0));
+    let diffuse = max(dot(N, light_dir), 0.0);
+
+    let ambient = 0.3;
+    let lighting = ambient + diffuse * 0.7;
+
+    let color = object.color.rgb * lighting;
+    return vec4f(color, 1.0);
+}