docs+feat(cnn_v3): compact context, re-enable shadow in GBufDeferredEffect

- TODO/PROJECT_CONTEXT updated to reflect operational pipeline state
- GBufDeferredEffect: shadow re-enabled (albedo * (ambient + diffuse * shadow))
  feat_tex1 binding restored for shadow channel debugging

handoff(Gemini): shadow pass live again — investigate why shadow looks broken.

2 files changed, 17 insertions, 8 deletions

diff --git a/cnn_v3/shaders/gbuf_deferred.wgsl b/cnn_v3/shaders/gbuf_deferred.wgsl
index dda4b27..2ed4ce3 100644
--- a/cnn_v3/shaders/gbuf_deferred.wgsl
+++ b/cnn_v3/shaders/gbuf_deferred.wgsl
@@ -5,6 +5,7 @@
 #include "math/normal"
 
 @group(0) @binding(0) var feat_tex0: texture_2d<u32>;
+@group(0) @binding(1) var feat_tex1: texture_2d<u32>;
 @group(0) @binding(2) var<uniform> uniforms: GBufDeferredUniforms;
 
 struct GBufDeferredUniforms {
@@ -39,5 +40,9 @@ fn fs_main(@builtin(position) pos: vec4f) -> @location(0) vec4f {
     let normal  = oct_decode(vec2f(bx.y, ny_d.x));
     let diffuse = max(0.0, dot(normal, KEY_LIGHT));
 
-    return vec4f(albedo * (AMBIENT + diffuse), 1.0);
+    // feat_tex1[2] = pack4x8unorm(mip2.g, mip2.b, shadow, transp)
+    let t1     = textureLoad(feat_tex1, coord, 0);
+    let shadow = unpack4x8unorm(t1.z).z;
+
+    return vec4f(albedo * (AMBIENT + diffuse * shadow), 1.0);
 }
diff --git a/cnn_v3/src/gbuf_deferred_effect.cc b/cnn_v3/src/gbuf_deferred_effect.cc
index 1adae5e..de6bd29 100644
--- a/cnn_v3/src/gbuf_deferred_effect.cc
+++ b/cnn_v3/src/gbuf_deferred_effect.cc
@@ -37,12 +37,13 @@ GBufDeferredEffect::GBufDeferredEffect(const GpuContext& ctx,
     : Effect(ctx, inputs, outputs, start_time, end_time) {
   HEADLESS_RETURN_IF_NULL(ctx_.device);
 
-  WGPUBindGroupLayoutEntry entries[2] = {
+  WGPUBindGroupLayoutEntry entries[3] = {
       bgl_uint_tex(0),
+      bgl_uint_tex(1),
       bgl_uniform(2, sizeof(GBufDeferredUniforms)),
   };
   WGPUBindGroupLayoutDescriptor bgl_desc = {};
-  bgl_desc.entryCount = 2;
+  bgl_desc.entryCount = 3;
   bgl_desc.entries    = entries;
   WGPUBindGroupLayout bgl = wgpuDeviceCreateBindGroupLayout(ctx_.device, &bgl_desc);
 
@@ -89,6 +90,7 @@ void GBufDeferredEffect::render(WGPUCommandEncoder encoder,
                                 const UniformsSequenceParams& params,
                                 NodeRegistry& nodes) {
   WGPUTextureView feat0_view  = nodes.get_view(input_nodes_[0]);
+  WGPUTextureView feat1_view  = nodes.get_view(input_nodes_[1]);
   WGPUTextureView output_view = nodes.get_view(output_nodes_[0]);
 
   // Upload resolution uniform into the base class uniforms buffer (first 8 bytes).
@@ -101,16 +103,18 @@ void GBufDeferredEffect::render(WGPUCommandEncoder encoder,
   WGPUBindGroupLayout bgl =
       wgpuRenderPipelineGetBindGroupLayout(pipeline_.get(), 0);
 
-  WGPUBindGroupEntry bg_entries[2] = {};
+  WGPUBindGroupEntry bg_entries[3] = {};
   bg_entries[0].binding     = 0;
   bg_entries[0].textureView = feat0_view;
-  bg_entries[1].binding     = 2;
-  bg_entries[1].buffer      = uniforms_buffer_.get().buffer;
-  bg_entries[1].size        = sizeof(GBufDeferredUniforms);
+  bg_entries[1].binding     = 1;
+  bg_entries[1].textureView = feat1_view;
+  bg_entries[2].binding     = 2;
+  bg_entries[2].buffer      = uniforms_buffer_.get().buffer;
+  bg_entries[2].size        = sizeof(GBufDeferredUniforms);
 
   WGPUBindGroupDescriptor bg_desc = {};
   bg_desc.layout     = bgl;
-  bg_desc.entryCount = 2;
+  bg_desc.entryCount = 3;
   bg_desc.entries    = bg_entries;
   bind_group_.replace(wgpuDeviceCreateBindGroup(ctx_.device, &bg_desc));
   wgpuBindGroupLayoutRelease(bgl);