Refactor: factorize common WGPU patterns into helper functions

Add texture creation helpers (gpu_create_texture_2d, gpu_create_storage_texture_2d,
gpu_create_mip_view) and extend BindGroupLayoutBuilder with uint_texture and
storage_texture methods.

Refactored files:
- cnn_v2_effect.cc: Use texture helpers (~70% code reduction in create_textures)
- rotating_cube_effect.cc: Use BindGroupLayoutBuilder and texture helpers
- circle_mask_effect.cc: Use BindGroupBuilder

Benefits:
- Improved code readability
- Reduced boilerplate for texture/bind group creation
- Consistent patterns across effects

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

1 files changed, 19 insertions, 48 deletions

diff --git a/src/gpu/effects/rotating_cube_effect.cc b/src/gpu/effects/rotating_cube_effect.cc
index cd31100..96b02f1 100644
--- a/src/gpu/effects/rotating_cube_effect.cc
+++ b/src/gpu/effects/rotating_cube_effect.cc
@@ -4,7 +4,9 @@
 
 #include "gpu/effects/rotating_cube_effect.h"
 #include "generated/assets.h"
+#include "gpu/bind_group_builder.h"
 #include "gpu/effects/shader_composer.h"
+#include "gpu/gpu.h"
 #include "gpu/sampler_cache.h"
 #include "util/asset_manager_utils.h"
 
@@ -35,17 +37,11 @@ void RotatingCubeEffect::init(MainSequence* demo) {
       gpu_create_buffer(ctx_.device, sizeof(ObjectData),
                         WGPUBufferUsage_Storage | WGPUBufferUsage_CopyDst);
 
-  const WGPUTextureDescriptor tex_desc = {
-      .usage =
-          WGPUTextureUsage_TextureBinding | WGPUTextureUsage_RenderAttachment,
-      .dimension = WGPUTextureDimension_2D,
-      .size = {1, 1, 1},
-      .format = WGPUTextureFormat_RGBA8Unorm,
-      .mipLevelCount = 1,
-      .sampleCount = 1,
-  };
-  noise_texture_ = wgpuDeviceCreateTexture(ctx_.device, &tex_desc);
-  noise_view_ = wgpuTextureCreateView(noise_texture_, nullptr);
+  TextureWithView noise = gpu_create_texture_2d(
+      ctx_.device, 1, 1, WGPUTextureFormat_RGBA8Unorm,
+      WGPUTextureUsage_TextureBinding | WGPUTextureUsage_RenderAttachment, 1);
+  noise_texture_ = noise.texture;
+  noise_view_ = noise.view;
 
   noise_sampler_ = SamplerCache::Get().get_or_create(ctx_.device, SamplerCache::linear());
   mask_sampler_ = SamplerCache::Get().get_or_create(ctx_.device, SamplerCache::clamp());
@@ -68,45 +64,20 @@ void RotatingCubeEffect::init(MainSequence* demo) {
   WGPUShaderModule shader_module =
       wgpuDeviceCreateShaderModule(ctx_.device, &shader_desc);
 
-  const WGPUBindGroupLayoutEntry bgl_entries_0[] = {
-      {.binding = 0,
-       .visibility = WGPUShaderStage_Vertex | WGPUShaderStage_Fragment,
-       .buffer = {.type = WGPUBufferBindingType_Uniform,
-                  .minBindingSize = sizeof(Uniforms)}},
-      {.binding = 1,
-       .visibility = WGPUShaderStage_Vertex | WGPUShaderStage_Fragment,
-       .buffer = {.type = WGPUBufferBindingType_ReadOnlyStorage,
-                  .minBindingSize = sizeof(ObjectData)}},
-      {.binding = 3,
-       .visibility = WGPUShaderStage_Fragment,
-       .texture = {.sampleType = WGPUTextureSampleType_Float,
-                   .viewDimension = WGPUTextureViewDimension_2D}},
-      {.binding = 4,
-       .visibility = WGPUShaderStage_Fragment,
-       .sampler = {.type = WGPUSamplerBindingType_Filtering}},
-  };
-  const WGPUBindGroupLayoutDescriptor bgl_desc_0 = {
-      .entryCount = 4,
-      .entries = bgl_entries_0,
-  };
   WGPUBindGroupLayout bgl_0 =
-      wgpuDeviceCreateBindGroupLayout(ctx_.device, &bgl_desc_0);
+      BindGroupLayoutBuilder()
+          .uniform(0, WGPUShaderStage_Vertex | WGPUShaderStage_Fragment,
+                   sizeof(Uniforms))
+          .storage(1, WGPUShaderStage_Vertex | WGPUShaderStage_Fragment,
+                   sizeof(ObjectData))
+          .texture(3, WGPUShaderStage_Fragment)
+          .sampler(4, WGPUShaderStage_Fragment)
+          .build(ctx_.device);
 
-  const WGPUBindGroupLayoutEntry bgl_entries_1[] = {
-      {.binding = 0,
-       .visibility = WGPUShaderStage_Fragment,
-       .texture = {.sampleType = WGPUTextureSampleType_Float,
-                   .viewDimension = WGPUTextureViewDimension_2D}},
-      {.binding = 1,
-       .visibility = WGPUShaderStage_Fragment,
-       .sampler = {.type = WGPUSamplerBindingType_Filtering}},
-  };
-  const WGPUBindGroupLayoutDescriptor bgl_desc_1 = {
-      .entryCount = 2,
-      .entries = bgl_entries_1,
-  };
-  WGPUBindGroupLayout bgl_1 =
-      wgpuDeviceCreateBindGroupLayout(ctx_.device, &bgl_desc_1);
+  WGPUBindGroupLayout bgl_1 = BindGroupLayoutBuilder()
+                                  .texture(0, WGPUShaderStage_Fragment)
+                                  .sampler(1, WGPUShaderStage_Fragment)
+                                  .build(ctx_.device);
 
   const WGPUBindGroupLayout bgls[] = {bgl_0, bgl_1};
   const WGPUPipelineLayoutDescriptor pl_desc = {