refactor(shaders): Apply common utilities to renderer shaders

Updated renderer_3d.wgsl, mesh_render.wgsl, skybox.wgsl to use
common_utils functions. Registered snippet in ShaderComposer.

Updated demo_assets.txt with SHADER_MATH_COMMON_UTILS entry.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

4 files changed, 18 insertions, 24 deletions

diff --git a/assets/final/demo_assets.txt b/assets/final/demo_assets.txt
index 6293696..256f246 100644
--- a/assets/final/demo_assets.txt
+++ b/assets/final/demo_assets.txt
@@ -41,6 +41,7 @@ SHADER_VISUAL_DEBUG, NONE, shaders/visual_debug.wgsl, "Visual Debug Shader"
 SHADER_SKYBOX, NONE, shaders/skybox.wgsl, "Skybox background shader"
 SHADER_MATH_SDF_SHAPES, NONE, shaders/math/sdf_shapes.wgsl, "SDF Shapes Snippet"
 SHADER_MATH_SDF_UTILS, NONE, shaders/math/sdf_utils.wgsl, "SDF Utils Snippet"
+SHADER_MATH_COMMON_UTILS, NONE, shaders/math/common_utils.wgsl, "Common Math Utils"
 SHADER_RENDER_SHADOWS, NONE, shaders/render/shadows.wgsl, "Shadows Snippet"
 SHADER_RENDER_SCENE_QUERY_BVH, NONE, shaders/render/scene_query_bvh.wgsl, "Scene Query Snippet (BVH)"
 SHADER_RENDER_SCENE_QUERY_LINEAR, NONE, shaders/render/scene_query_linear.wgsl, "Scene Query Snippet (Linear)"
diff --git a/assets/final/shaders/mesh_render.wgsl b/assets/final/shaders/mesh_render.wgsl
index 068efbc..7390b06 100644
--- a/assets/final/shaders/mesh_render.wgsl
+++ b/assets/final/shaders/mesh_render.wgsl
@@ -1,4 +1,5 @@
 #include "common_uniforms"
+#include "math/common_utils"
 
 @group(0) @binding(0) var<uniform> globals: GlobalUniforms;
 @group(0) @binding(1) var<storage, read> object_data: ObjectsBuffer;
@@ -33,10 +34,8 @@ fn vs_main(in: VertexInput, @builtin(instance_index) instance_index: u32) -> Ver
     out.clip_pos = globals.view_proj * world_pos;
     out.world_pos = world_pos.xyz;
     
-    // Use transpose of inverse for normals
-    // Note: mat3x3 constructor takes columns, so passing rows gives us transpose
-    let normal_matrix = mat3x3<f32>(obj.inv_model[0].xyz, obj.inv_model[1].xyz, obj.inv_model[2].xyz);
-    out.normal = normalize(normal_matrix * in.normal);
+    // Transform normal from local to world space
+    out.normal = transform_normal(obj.inv_model, in.normal);
     
     out.uv = in.uv;
     out.color = obj.color;
diff --git a/assets/final/shaders/renderer_3d.wgsl b/assets/final/shaders/renderer_3d.wgsl
index c290df8..1183e3c 100644
--- a/assets/final/shaders/renderer_3d.wgsl
+++ b/assets/final/shaders/renderer_3d.wgsl
@@ -1,4 +1,5 @@
 #include "common_uniforms"
+#include "math/common_utils"
 
 @group(0) @binding(0) var<uniform> globals: GlobalUniforms;
 @group(0) @binding(1) var<storage, read> object_data: ObjectsBuffer;
@@ -100,8 +101,7 @@ fn fs_main(in: VertexOutput) -> FragmentOutput {
 
         // Apply grid pattern to floor
         let uv = p.xz * 0.5;
-        let grid = 0.5 + 0.5 * sin(uv.x * 3.14) * sin(uv.y * 3.14);
-        let grid_val = smoothstep(0.45, 0.55, grid);
+        let grid_val = grid_pattern(uv);
         base_color = base_color * (0.5 + 0.5 * grid_val);
     } else { // SDF path
         let ro_world = globals.camera_pos_time.xyz;
@@ -140,48 +140,45 @@ fn fs_main(in: VertexOutput) -> FragmentOutput {
         let disp_strength = 0.05;
         
         let q_x1 = q_hit + e.xyy;
-        let uv_x1 = vec2<f32>(atan2(q_x1.x, q_x1.z) / 6.28 + 0.5, acos(clamp(q_x1.y / length(q_x1), -1.0, 1.0)) / 3.14);
+        let uv_x1 = spherical_uv(q_x1);
         let h_x1 = textureSample(noise_tex, noise_sampler, uv_x1).r;
         let d_x1 = get_dist(q_x1, obj.params) - disp_strength * h_x1;
         
         let q_x2 = q_hit - e.xyy;
-        let uv_x2 = vec2<f32>(atan2(q_x2.x, q_x2.z) / 6.28 + 0.5, acos(clamp(q_x2.y / length(q_x2), -1.0, 1.0)) / 3.14);
+        let uv_x2 = spherical_uv(q_x2);
         let h_x2 = textureSample(noise_tex, noise_sampler, uv_x2).r;
         let d_x2 = get_dist(q_x2, obj.params) - disp_strength * h_x2;
         
         let q_y1 = q_hit + e.yxy;
-        let uv_y1 = vec2<f32>(atan2(q_y1.x, q_y1.z) / 6.28 + 0.5, acos(clamp(q_y1.y / length(q_y1), -1.0, 1.0)) / 3.14);
+        let uv_y1 = spherical_uv(q_y1);
         let h_y1 = textureSample(noise_tex, noise_sampler, uv_y1).r;
         let d_y1 = get_dist(q_y1, obj.params) - disp_strength * h_y1;
         
         let q_y2 = q_hit - e.yxy;
-        let uv_y2 = vec2<f32>(atan2(q_y2.x, q_y2.z) / 6.28 + 0.5, acos(clamp(q_y2.y / length(q_y2), -1.0, 1.0)) / 3.14);
+        let uv_y2 = spherical_uv(q_y2);
         let h_y2 = textureSample(noise_tex, noise_sampler, uv_y2).r;
         let d_y2 = get_dist(q_y2, obj.params) - disp_strength * h_y2;
         
         let q_z1 = q_hit + e.yyx;
-        let uv_z1 = vec2<f32>(atan2(q_z1.x, q_z1.z) / 6.28 + 0.5, acos(clamp(q_z1.y / length(q_z1), -1.0, 1.0)) / 3.14);
+        let uv_z1 = spherical_uv(q_z1);
         let h_z1 = textureSample(noise_tex, noise_sampler, uv_z1).r;
         let d_z1 = get_dist(q_z1, obj.params) - disp_strength * h_z1;
         
         let q_z2 = q_hit - e.yyx;
-        let uv_z2 = vec2<f32>(atan2(q_z2.x, q_z2.z) / 6.28 + 0.5, acos(clamp(q_z2.y / length(q_z2), -1.0, 1.0)) / 3.14);
+        let uv_z2 = spherical_uv(q_z2);
         let h_z2 = textureSample(noise_tex, noise_sampler, uv_z2).r;
         let d_z2 = get_dist(q_z2, obj.params) - disp_strength * h_z2;
         
         let n_local = normalize(vec3<f32>(d_x1 - d_x2, d_y1 - d_y2, d_z1 - d_z2));
-        // Note: mat3x3 constructor takes columns, so passing rows gives us transpose
-        let normal_matrix = mat3x3<f32>(obj.inv_model[0].xyz, obj.inv_model[1].xyz, obj.inv_model[2].xyz);
-        normal = normalize(normal_matrix * n_local);
+        normal = transform_normal(obj.inv_model, n_local);
 
         // Apply texture to SDF color
         if (in.instance_index == 0u || obj_type == 4.0) { // Floor (index 0) or PLANE
             let uv_grid = p.xz * 0.5;
-            let grid = 0.5 + 0.5 * sin(uv_grid.x * 3.14) * sin(uv_grid.y * 3.14);
-            let grid_val = smoothstep(0.45, 0.55, grid);
+            let grid_val = grid_pattern(uv_grid);
             base_color = base_color * (0.5 + 0.5 * grid_val);
         } else {
-            let uv_hit = vec2<f32>(atan2(q_hit.x, q_hit.z) / 6.28 + 0.5, acos(clamp(q_hit.y / length(q_hit), -1.0, 1.0)) / 3.14);
+            let uv_hit = spherical_uv(q_hit);
             let tex_val = textureSample(noise_tex, noise_sampler, uv_hit).r;
             base_color = base_color * (0.7 + 0.3 * tex_val);
         }
diff --git a/assets/final/shaders/skybox.wgsl b/assets/final/shaders/skybox.wgsl
index d7f252e..31bea3b 100644
--- a/assets/final/shaders/skybox.wgsl
+++ b/assets/final/shaders/skybox.wgsl
@@ -1,4 +1,5 @@
 #include "common_uniforms"
+#include "math/common_utils"
 
 @group(0) @binding(0) var sky_tex: texture_2d<f32>;
 @group(0) @binding(1) var sky_sampler: sampler;
@@ -36,10 +37,6 @@ fn fs_main(in: VertexOutput) -> @location(0) vec4<f32> {
     let world_pos = world_pos_h.xyz / world_pos_h.w;
     
     let ray_dir = normalize(world_pos - globals.camera_pos_time.xyz);
-    
-    // Spherical Mapping
-    let u = atan2(ray_dir.z, ray_dir.x) / 6.28318 + 0.5;
-    let v = asin(clamp(ray_dir.y, -1.0, 1.0)) / 3.14159 + 0.5;
-    
-    return textureSample(sky_tex, sky_sampler, vec2<f32>(u, v));
+    let uv = spherical_uv_from_dir(ray_dir);
+    return textureSample(sky_tex, sky_sampler, uv);
 }
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