refactor(cnn_v3): GBufferEffect cleanupHEADmain

Remove dead code and reduce duplication:
- drop create_bilinear_sampler() (never called)
- drop update_pack_bind_group() stub and pack_bind_group_ member
- drop node_feat0_/node_feat1_; use output_nodes_[0/1] directly
- Compose({}, src) consistently for all three pipelines
- extract clear_r8_node() helper to replace two identical 10-line blocks

No behavior change. 36/36 tests pass.

2 files changed, 25 insertions, 57 deletions

diff --git a/cnn_v3/src/gbuffer_effect.cc b/cnn_v3/src/gbuffer_effect.cc
index 89ed8fc..06e5e66 100644
--- a/cnn_v3/src/gbuffer_effect.cc
+++ b/cnn_v3/src/gbuffer_effect.cc
@@ -42,18 +42,6 @@ struct GBufGlobalUniforms {
 static_assert(sizeof(GBufGlobalUniforms) == sizeof(float) * 44,
               "GBufGlobalUniforms must be 176 bytes");
 
-// Create bilinear sampler.
-static WGPUSampler create_bilinear_sampler(WGPUDevice device) {
-  WGPUSamplerDescriptor desc = {};
-  desc.addressModeU = WGPUAddressMode_ClampToEdge;
-  desc.addressModeV = WGPUAddressMode_ClampToEdge;
-  desc.magFilter = WGPUFilterMode_Linear;
-  desc.minFilter = WGPUFilterMode_Linear;
-  desc.mipmapFilter = WGPUMipmapFilterMode_Linear;
-  desc.maxAnisotropy = 1;
-  return wgpuDeviceCreateSampler(device, &desc);
-}
-
 // ---- GBufferEffect ----
 
 GBufferEffect::GBufferEffect(const GpuContext& ctx,
@@ -70,9 +58,6 @@ GBufferEffect::GBufferEffect(const GpuContext& ctx,
   node_depth_      = prefix + "_depth";
   node_shadow_     = prefix + "_shadow";
   node_transp_     = prefix + "_transp";
-  node_feat0_      = outputs.size() > 0 ? outputs[0] : prefix + "_feat0";
-  node_feat1_      = outputs.size() > 1 ? outputs[1] : prefix + "_feat1";
-
   // Allocate GPU buffers for scene data.
   global_uniforms_buf_ =
       gpu_create_buffer(ctx_.device, sizeof(GBufGlobalUniforms),
@@ -99,11 +84,11 @@ void GBufferEffect::declare_nodes(NodeRegistry& registry) {
   registry.declare_node(node_transp_,     NodeType::GBUF_R8,        -1, -1);
   // feat_tex0 / feat_tex1 are the declared output_nodes_ — they get registered
   // by the sequence infrastructure; declare them here as well if not already.
-  if (!registry.has_node(node_feat0_)) {
-    registry.declare_node(node_feat0_, NodeType::GBUF_RGBA32UINT, -1, -1);
+  if (!registry.has_node(output_nodes_[0])) {
+    registry.declare_node(output_nodes_[0], NodeType::GBUF_RGBA32UINT, -1, -1);
   }
-  if (!registry.has_node(node_feat1_)) {
-    registry.declare_node(node_feat1_, NodeType::GBUF_RGBA32UINT, -1, -1);
+  if (!registry.has_node(output_nodes_[1])) {
+    registry.declare_node(output_nodes_[1], NodeType::GBUF_RGBA32UINT, -1, -1);
   }
 }
 
@@ -178,6 +163,22 @@ void GBufferEffect::set_scene() {
   scene_ready_ = true;
 }
 
+static void clear_r8_node(WGPUCommandEncoder encoder, WGPUTextureView view,
+                           float value) {
+  WGPURenderPassColorAttachment att = {};
+  att.view       = view;
+  att.loadOp     = WGPULoadOp_Clear;
+  att.storeOp    = WGPUStoreOp_Store;
+  att.clearValue = {value, value, value, value};
+  att.depthSlice = WGPU_DEPTH_SLICE_UNDEFINED;
+  WGPURenderPassDescriptor pd = {};
+  pd.colorAttachmentCount = 1;
+  pd.colorAttachments     = &att;
+  WGPURenderPassEncoder p = wgpuCommandEncoderBeginRenderPass(encoder, &pd);
+  wgpuRenderPassEncoderEnd(p);
+  wgpuRenderPassEncoderRelease(p);
+}
+
 void GBufferEffect::render(WGPUCommandEncoder encoder,
                            const UniformsSequenceParams& params,
                            NodeRegistry& nodes) {
@@ -225,8 +226,8 @@ void GBufferEffect::render(WGPUCommandEncoder encoder,
   WGPUTextureView albedo_view     = nodes.get_view(node_albedo_);
   WGPUTextureView normal_mat_view = nodes.get_view(node_normal_mat_);
   WGPUTextureView depth_view      = nodes.get_view(node_depth_);
-  WGPUTextureView feat0_view      = nodes.get_view(node_feat0_);
-  WGPUTextureView feat1_view      = nodes.get_view(node_feat1_);
+  WGPUTextureView feat0_view      = nodes.get_view(output_nodes_[0]);
+  WGPUTextureView feat1_view      = nodes.get_view(output_nodes_[1]);
 
   // prev_cnn: first input node if available, else dummy.
   WGPUTextureView prev_view = nullptr;
@@ -340,36 +341,11 @@ void GBufferEffect::render(WGPUCommandEncoder encoder,
     wgpuBindGroupRelease(shadow_bg);
   } else {
     // Fallback: clear to 1.0 (fully lit) if pipeline not ready.
-    WGPURenderPassColorAttachment att = {};
-    att.view       = nodes.get_view(node_shadow_);
-    att.loadOp     = WGPULoadOp_Clear;
-    att.storeOp    = WGPUStoreOp_Store;
-    att.clearValue = {1.0f, 1.0f, 1.0f, 1.0f};
-    att.depthSlice = WGPU_DEPTH_SLICE_UNDEFINED;
-    WGPURenderPassDescriptor pd = {};
-    pd.colorAttachmentCount = 1;
-    pd.colorAttachments     = &att;
-    WGPURenderPassEncoder p = wgpuCommandEncoderBeginRenderPass(encoder, &pd);
-    wgpuRenderPassEncoderEnd(p);
-    wgpuRenderPassEncoderRelease(p);
+    clear_r8_node(encoder, nodes.get_view(node_shadow_), 1.0f);
   }
 
   // Pass 3: Transparency — TODO (deferred; opaque scenes only)
-  // Clear transp node to 0.0 (fully opaque) until pass 3 is implemented.
-  {
-    WGPURenderPassColorAttachment att = {};
-    att.view       = nodes.get_view(node_transp_);
-    att.loadOp     = WGPULoadOp_Clear;
-    att.storeOp    = WGPUStoreOp_Store;
-    att.clearValue = {0.0f, 0.0f, 0.0f, 0.0f};
-    att.depthSlice = WGPU_DEPTH_SLICE_UNDEFINED;
-    WGPURenderPassDescriptor pd = {};
-    pd.colorAttachmentCount = 1;
-    pd.colorAttachments     = &att;
-    WGPURenderPassEncoder p = wgpuCommandEncoderBeginRenderPass(encoder, &pd);
-    wgpuRenderPassEncoderEnd(p);
-    wgpuRenderPassEncoderRelease(p);
-  }
+  clear_r8_node(encoder, nodes.get_view(node_transp_), 0.0f);
 
   // --- Pass 4: Pack compute ---
   // Rebuild pack bind group with current node views.
@@ -509,7 +485,7 @@ void GBufferEffect::create_raster_pipeline() {
   }
 
   const std::string composed =
-      ShaderComposer::Get().Compose({"common_uniforms"}, src);
+      ShaderComposer::Get().Compose({}, src);
 
   WGPUShaderSourceWGSL wgsl_src = {};
   wgsl_src.chain.sType = WGPUSType_ShaderSourceWGSL;
@@ -793,7 +769,3 @@ void GBufferEffect::update_raster_bind_group(NodeRegistry& nodes) {
   wgpuBindGroupLayoutRelease(bgl);
 }
 
-void GBufferEffect::update_pack_bind_group(NodeRegistry& nodes) {
-  (void)nodes;
-  // Pack bind group is rebuilt inline in render() to use current node views.
-}
diff --git a/cnn_v3/src/gbuffer_effect.h b/cnn_v3/src/gbuffer_effect.h
index c39219b..13d394d 100644
--- a/cnn_v3/src/gbuffer_effect.h
+++ b/cnn_v3/src/gbuffer_effect.h
@@ -68,8 +68,6 @@ class GBufferEffect : public Effect {
   std::string node_depth_;
   std::string node_shadow_;
   std::string node_transp_;
-  std::string node_feat0_;
-  std::string node_feat1_;
 
   // Owned scene and camera — populated by set_scene()
   Scene  scene_;
@@ -88,7 +86,6 @@ class GBufferEffect : public Effect {
 
   // Pass 4: Pack compute pipeline
   ComputePipeline  pack_pipeline_;
-  BindGroup        pack_bind_group_;
   UniformBuffer<GBufResUniforms>    pack_res_uniform_;
   UniformBuffer<GBufLightsUniforms> lights_uniform_;
 
@@ -102,7 +99,6 @@ class GBufferEffect : public Effect {
   void create_pack_pipeline();
 
   void update_raster_bind_group(NodeRegistry& nodes);
-  void update_pack_bind_group(NodeRegistry& nodes);
 
   void upload_scene_data(const Scene& scene, const Camera& camera,
                          float time);