CNN v2: bilinear mip-level sampling and UI improvements

**CNN v2 Changes:**
- Replace point sampling with bilinear interpolation for mip-level features
- Add linear sampler (binding 6) to static features shader
- Update CNNv2Effect, cnn_test, and HTML tool

**HTML Tool UI:**
- Move controls to floating bottom bar in central view
- Consolidate video controls + Blend/Depth/Save PNG in single container
- Increase left panel width: 300px → 315px (+5%)
- Remove per-frame debug messages (visualization, rendering logs)

**Technical:**
- WGSL: textureSample() with linear_sampler vs textureLoad()
- C++: Create WGPUSampler with Linear filtering
- HTML: Change sampler from 'nearest' to 'linear'

handoff(Claude): CNN v2 now uses bilinear mip-level sampling across all tools

7 files changed, 116 insertions, 49 deletions

diff --git a/.gitignore b/.gitignore
index 4c783d7..41d0683 100644
--- a/.gitignore
+++ b/.gitignore
@@ -68,4 +68,5 @@ timeline.txt
 timeline.html
 Testing/
 training/checkpoints/
+checkpoints/
 validation_results/
diff --git a/src/gpu/effects/cnn_v2_effect.cc b/src/gpu/effects/cnn_v2_effect.cc
index 366a232..d412154 100644
--- a/src/gpu/effects/cnn_v2_effect.cc
+++ b/src/gpu/effects/cnn_v2_effect.cc
@@ -19,6 +19,7 @@ CNNv2Effect::CNNv2Effect(const GpuContext& ctx)
       static_params_buffer_(nullptr),
       static_features_tex_(nullptr),
       static_features_view_(nullptr),
+      linear_sampler_(nullptr),
       layer_pipeline_(nullptr),
       weights_buffer_(nullptr),
       input_mip_tex_(nullptr),
@@ -36,6 +37,7 @@ CNNv2Effect::CNNv2Effect(const GpuContext& ctx, const CNNv2EffectParams& params)
       static_params_buffer_(nullptr),
       static_features_tex_(nullptr),
       static_features_view_(nullptr),
+      linear_sampler_(nullptr),
       layer_pipeline_(nullptr),
       weights_buffer_(nullptr),
       input_mip_tex_(nullptr),
@@ -221,6 +223,20 @@ void CNNv2Effect::create_textures() {
 }
 
 void CNNv2Effect::create_pipelines() {
+  // Create linear sampler for bilinear interpolation
+  WGPUSamplerDescriptor sampler_desc = {};
+  sampler_desc.addressModeU = WGPUAddressMode_ClampToEdge;
+  sampler_desc.addressModeV = WGPUAddressMode_ClampToEdge;
+  sampler_desc.addressModeW = WGPUAddressMode_ClampToEdge;
+  sampler_desc.magFilter = WGPUFilterMode_Linear;
+  sampler_desc.minFilter = WGPUFilterMode_Linear;
+  sampler_desc.mipmapFilter = WGPUMipmapFilterMode_Linear;
+  sampler_desc.lodMinClamp = 0.0f;
+  sampler_desc.lodMaxClamp = 32.0f;
+  sampler_desc.maxAnisotropy = 1;
+
+  linear_sampler_ = wgpuDeviceCreateSampler(ctx_.device, &sampler_desc);
+
   // Static features compute pipeline
   size_t shader_size = 0;
   const char* static_code = (const char*)GetAsset(AssetId::ASSET_SHADER_CNN_V2_STATIC, &shader_size);
@@ -238,8 +254,8 @@ void CNNv2Effect::create_pipelines() {
   shader_desc.nextInChain = &wgsl_src.chain;
 
   // Create bind group layout for static features compute
-  // Bindings: 0=input_tex, 1=input_mip1, 2=input_mip2, 3=depth_tex, 4=output, 5=params
-  WGPUBindGroupLayoutEntry bgl_entries[6] = {};
+  // Bindings: 0=input_tex, 1=input_mip1, 2=input_mip2, 3=depth_tex, 4=output, 5=params, 6=linear_sampler
+  WGPUBindGroupLayoutEntry bgl_entries[7] = {};
 
   // Binding 0: Input texture (mip 0)
   bgl_entries[0].binding = 0;
@@ -278,8 +294,13 @@ void CNNv2Effect::create_pipelines() {
   bgl_entries[5].buffer.type = WGPUBufferBindingType_Uniform;
   bgl_entries[5].buffer.minBindingSize = sizeof(StaticFeatureParams);
 
+  // Binding 6: Linear sampler (for bilinear interpolation)
+  bgl_entries[6].binding = 6;
+  bgl_entries[6].visibility = WGPUShaderStage_Compute;
+  bgl_entries[6].sampler.type = WGPUSamplerBindingType_Filtering;
+
   WGPUBindGroupLayoutDescriptor bgl_desc = {};
-  bgl_desc.entryCount = 6;
+  bgl_desc.entryCount = 7;
   bgl_desc.entries = bgl_entries;
 
   WGPUBindGroupLayout static_bgl = wgpuDeviceCreateBindGroupLayout(ctx_.device, &bgl_desc);
@@ -398,7 +419,7 @@ void CNNv2Effect::update_bind_group(WGPUTextureView input_view) {
   }
 
   // Create bind group for static features compute
-  WGPUBindGroupEntry bg_entries[6] = {};
+  WGPUBindGroupEntry bg_entries[7] = {};
 
   // Binding 0: Input (mip 0)
   bg_entries[0].binding = 0;
@@ -425,9 +446,13 @@ void CNNv2Effect::update_bind_group(WGPUTextureView input_view) {
   bg_entries[5].buffer = static_params_buffer_;
   bg_entries[5].size = sizeof(StaticFeatureParams);
 
+  // Binding 6: Linear sampler
+  bg_entries[6].binding = 6;
+  bg_entries[6].sampler = linear_sampler_;
+
   WGPUBindGroupDescriptor bg_desc = {};
   bg_desc.layout = wgpuComputePipelineGetBindGroupLayout(static_pipeline_, 0);
-  bg_desc.entryCount = 6;
+  bg_desc.entryCount = 7;
   bg_desc.entries = bg_entries;
 
   static_bind_group_ = wgpuDeviceCreateBindGroup(ctx_.device, &bg_desc);
@@ -563,6 +588,7 @@ void CNNv2Effect::cleanup() {
   if (static_bind_group_) wgpuBindGroupRelease(static_bind_group_);
   if (static_params_buffer_) wgpuBufferRelease(static_params_buffer_);
   if (static_pipeline_) wgpuComputePipelineRelease(static_pipeline_);
+  if (linear_sampler_) wgpuSamplerRelease(linear_sampler_);
 
   if (layer_pipeline_) wgpuComputePipelineRelease(layer_pipeline_);
   if (weights_buffer_) wgpuBufferRelease(weights_buffer_);
diff --git a/src/gpu/effects/cnn_v2_effect.h b/src/gpu/effects/cnn_v2_effect.h
index 8a2e1b6..d530d3b 100644
--- a/src/gpu/effects/cnn_v2_effect.h
+++ b/src/gpu/effects/cnn_v2_effect.h
@@ -64,6 +64,7 @@ private:
   WGPUBuffer static_params_buffer_;
   WGPUTexture static_features_tex_;
   WGPUTextureView static_features_view_;
+  WGPUSampler linear_sampler_;
 
   // CNN layers (storage buffer architecture)
   WGPUComputePipeline layer_pipeline_;      // Single pipeline for all layers
diff --git a/tools/cnn_test.cc b/tools/cnn_test.cc
index c504c3d..b4a4bdc 100644
--- a/tools/cnn_test.cc
+++ b/tools/cnn_test.cc
@@ -784,6 +784,20 @@ static bool process_cnn_v2(WGPUDevice device, WGPUQueue queue,
   wgpuQueueWriteBuffer(queue, static_params_buffer, 0, &static_params,
                        sizeof(static_params));
 
+  // Create linear sampler for bilinear interpolation
+  WGPUSamplerDescriptor linear_sampler_desc = {};
+  linear_sampler_desc.addressModeU = WGPUAddressMode_ClampToEdge;
+  linear_sampler_desc.addressModeV = WGPUAddressMode_ClampToEdge;
+  linear_sampler_desc.addressModeW = WGPUAddressMode_ClampToEdge;
+  linear_sampler_desc.magFilter = WGPUFilterMode_Linear;
+  linear_sampler_desc.minFilter = WGPUFilterMode_Linear;
+  linear_sampler_desc.mipmapFilter = WGPUMipmapFilterMode_Linear;
+  linear_sampler_desc.lodMinClamp = 0.0f;
+  linear_sampler_desc.lodMaxClamp = 32.0f;
+  linear_sampler_desc.maxAnisotropy = 1;
+
+  WGPUSampler linear_sampler = wgpuDeviceCreateSampler(device, &linear_sampler_desc);
+
   // Create static features compute pipeline
   WGPUShaderSourceWGSL static_wgsl = {};
   static_wgsl.chain.sType = WGPUSType_ShaderSourceWGSL;
@@ -796,8 +810,8 @@ static bool process_cnn_v2(WGPUDevice device, WGPUQueue queue,
       wgpuDeviceCreateShaderModule(device, &static_module_desc);
 
   // Bind group layout: 0=input, 1=input_mip1, 2=input_mip2, 3=depth, 4=output,
-  // 5=params
-  WGPUBindGroupLayoutEntry static_bgl_entries[6] = {};
+  // 5=params, 6=linear_sampler
+  WGPUBindGroupLayoutEntry static_bgl_entries[7] = {};
   static_bgl_entries[0].binding = 0;
   static_bgl_entries[0].visibility = WGPUShaderStage_Compute;
   static_bgl_entries[0].texture.sampleType = WGPUTextureSampleType_Float;
@@ -832,8 +846,12 @@ static bool process_cnn_v2(WGPUDevice device, WGPUQueue queue,
   static_bgl_entries[5].buffer.minBindingSize =
       sizeof(CNNv2StaticFeatureParams);
 
+  static_bgl_entries[6].binding = 6;
+  static_bgl_entries[6].visibility = WGPUShaderStage_Compute;
+  static_bgl_entries[6].sampler.type = WGPUSamplerBindingType_Filtering;
+
   WGPUBindGroupLayoutDescriptor static_bgl_desc = {};
-  static_bgl_desc.entryCount = 6;
+  static_bgl_desc.entryCount = 7;
   static_bgl_desc.entries = static_bgl_entries;
 
   WGPUBindGroupLayout static_bgl =
@@ -858,7 +876,7 @@ static bool process_cnn_v2(WGPUDevice device, WGPUQueue queue,
   wgpuPipelineLayoutRelease(static_pl);
 
   // Create static bind group (use input as all mips for simplicity)
-  WGPUBindGroupEntry static_bg_entries[6] = {};
+  WGPUBindGroupEntry static_bg_entries[7] = {};
   static_bg_entries[0].binding = 0;
   static_bg_entries[0].textureView = input_view;
   static_bg_entries[1].binding = 1;
@@ -872,10 +890,12 @@ static bool process_cnn_v2(WGPUDevice device, WGPUQueue queue,
   static_bg_entries[5].binding = 5;
   static_bg_entries[5].buffer = static_params_buffer;
   static_bg_entries[5].size = sizeof(CNNv2StaticFeatureParams);
+  static_bg_entries[6].binding = 6;
+  static_bg_entries[6].sampler = linear_sampler;
 
   WGPUBindGroupDescriptor static_bg_desc = {};
   static_bg_desc.layout = static_bgl;
-  static_bg_desc.entryCount = 6;
+  static_bg_desc.entryCount = 7;
   static_bg_desc.entries = static_bg_entries;
 
   WGPUBindGroup static_bg = wgpuDeviceCreateBindGroup(device, &static_bg_desc);
diff --git a/tools/cnn_v2_test/index.html b/tools/cnn_v2_test/index.html
index 2ec934d..e226d0c 100644
--- a/tools/cnn_v2_test/index.html
+++ b/tools/cnn_v2_test/index.html
@@ -104,7 +104,7 @@
       background: #404040;
     }
     .left-sidebar {
-      width: 300px;
+      width: 315px;
       background: #2a2a2a;
       overflow-y: auto;
       display: flex;
@@ -135,6 +135,32 @@
       border: 1px solid #404040;
       z-index: 100;
     }
+    .bottom-controls-float {
+      position: absolute;
+      bottom: 16px;
+      left: 50%;
+      transform: translateX(-50%);
+      display: flex;
+      gap: 16px;
+      align-items: center;
+      background: rgba(42, 42, 42, 0.95);
+      padding: 8px 16px;
+      border-radius: 4px;
+      border: 1px solid #404040;
+      z-index: 100;
+    }
+    .bottom-controls-float .control-group {
+      display: flex;
+      gap: 8px;
+      align-items: center;
+    }
+    .bottom-controls-float #videoControls {
+      display: flex;
+      gap: 8px;
+      align-items: center;
+      padding-right: 16px;
+      border-right: 1px solid #404040;
+    }
     .main.drop-active::after {
       content: 'Drop PNG/video here';
       position: absolute;
@@ -312,19 +338,6 @@
 <body>
   <div class="header">
     <h1>CNN v2 Testing Tool</h1>
-    <div class="controls">
-      <div class="control-group">
-        <label>Blend:</label>
-        <input type="range" id="blend" min="0" max="1" step="0.01" value="1.0">
-        <span id="blendValue">1.0</span>
-      </div>
-      <div class="control-group">
-        <label>Depth:</label>
-        <input type="range" id="depth" min="0" max="1" step="0.01" value="1.0">
-        <span id="depthValue">1.0</span>
-      </div>
-      <button id="savePngBtn">Save PNG</button>
-    </div>
   </div>
   <video id="videoSource" muted loop></video>
   <div class="content">
@@ -358,10 +371,23 @@
       </div>
     </div>
     <div class="main" id="mainDrop">
-      <div class="video-controls-float" id="videoControls">
-        <button id="playPauseBtn" disabled>Play</button>
-        <button id="stepBackBtn" disabled>◄ Frame</button>
-        <button id="stepForwardBtn" disabled>Frame ►</button>
+      <div class="bottom-controls-float">
+        <div id="videoControls">
+          <button id="playPauseBtn" disabled>Play</button>
+          <button id="stepBackBtn" disabled>◄ Frame</button>
+          <button id="stepForwardBtn" disabled>Frame ►</button>
+        </div>
+        <div class="control-group">
+          <label>Blend:</label>
+          <input type="range" id="blend" min="0" max="1" step="0.01" value="1.0">
+          <span id="blendValue">1.0</span>
+        </div>
+        <div class="control-group">
+          <label>Depth:</label>
+          <input type="range" id="depth" min="0" max="1" step="0.01" value="1.0">
+          <span id="depthValue">1.0</span>
+        </div>
+        <button id="savePngBtn">Save PNG</button>
       </div>
       <canvas id="canvas"></canvas>
     </div>
@@ -409,7 +435,7 @@ fn vs_main(@builtin(vertex_index) idx: u32) -> @builtin(position) vec4<f32> {
 // Static features: 7D parametric features (RGBD + UV + sin(10*uv_x) + bias)
 const STATIC_SHADER = `
 @group(0) @binding(0) var input_tex: texture_2d<f32>;
-@group(0) @binding(1) var point_sampler: sampler;
+@group(0) @binding(1) var linear_sampler: sampler;
 @group(0) @binding(2) var depth_tex: texture_2d<f32>;
 @group(0) @binding(3) var output_tex: texture_storage_2d<rgba32uint, write>;
 @group(0) @binding(4) var<uniform> mip_level: u32;
@@ -420,9 +446,9 @@ fn main(@builtin(global_invocation_id) id: vec3<u32>) {
   let dims = textureDimensions(input_tex);
   if (coord.x >= i32(dims.x) || coord.y >= i32(dims.y)) { return; }
 
-  // Use normalized UV coords with point sampler (no filtering)
+  // Use normalized UV coords with linear sampler (bilinear filtering)
   let uv = (vec2<f32>(coord) + 0.5) / vec2<f32>(dims);
-  let rgba = textureSampleLevel(input_tex, point_sampler, uv, f32(mip_level));
+  let rgba = textureSampleLevel(input_tex, linear_sampler, uv, f32(mip_level));
 
   let p0 = rgba.r;
   let p1 = rgba.g;
@@ -1114,8 +1140,6 @@ class CNNTester {
     if (!source) return;
     const { width, height } = this.getDimensions();
 
-    this.log(`Running CNN pipeline (${this.weights.layers.length} layers)...`);
-
     this.context.configure({ device: this.device, format: this.format });
 
     // Create persistent input texture for original view with mipmaps
@@ -1203,9 +1227,9 @@ class CNNTester {
 
     if (!this.pointSampler) {
       this.pointSampler = this.device.createSampler({
-        magFilter: 'nearest',
-        minFilter: 'nearest',
-        mipmapFilter: 'nearest'
+        magFilter: 'linear',
+        minFilter: 'linear',
+        mipmapFilter: 'linear'
       });
     }
 
@@ -1464,8 +1488,6 @@ class CNNTester {
     const layerTex = this.layerOutputs[layerIdx];
     const { width, height } = this.getDimensions();
 
-    this.log(`Visualizing ${layerName} activations (${width}×${height})`);
-
     // Update channel labels based on layer type
     // Static features (layerIdx=0): 8 channels split into two views
     // CNN layers (layerIdx≥1): 4 channels per layer
@@ -1519,7 +1541,6 @@ class CNNTester {
 
       try {
         ctx.configure({ device: this.device, format: this.format });
-        this.log(`Canvas ${c}: ${width}×${height}, WebGPU context configured`);
       } catch (e) {
         this.log(`Failed to configure canvas ${c}: ${e.message}`, 'error');
         continue;
@@ -1559,12 +1580,10 @@ class CNNTester {
       renderPass.end();
 
       this.device.queue.submit([encoder.finish()]);
-      this.log(`Submitted render for channel ${c}`);
     }
 
     // Wait for all renders to complete
     await this.device.queue.onSubmittedWorkDone();
-    this.log(`Rendered 4 channels for ${layerName}`);
 
     // Update active channel highlighting and preview
     this.updateChannelSelection();
@@ -1666,7 +1685,6 @@ class CNNTester {
     if (btn) btn.classList.add('active');
 
     const { kernelSize, inChannels, outChannels, weightOffset, min, max } = layer;
-    this.log(`Visualizing Layer ${cnnLayerIdx} weights: ${inChannels}→${outChannels}, ${kernelSize}×${kernelSize}`);
 
     const canvas = document.getElementById('weightsCanvas');
     const ctx = canvas.getContext('2d', { willReadFrequently: false });
@@ -1706,8 +1724,6 @@ class CNNTester {
         }
       }
     }
-
-    this.log(`Rendered ${outChannels} output channels (${width}×${height}px)`);
   }
 
   getWeightValue(idx) {
diff --git a/training/layers/chk_10000_3x5x3x3.pt b/training/layers/chk_10000_3x5x3x3.pt
new file mode 100644
index 0000000..6e6750c
--- /dev/null
+++ b/training/layers/chk_10000_3x5x3x3.pt
diff --git a/workspaces/main/shaders/cnn_v2/cnn_v2_static.wgsl b/workspaces/main/shaders/cnn_v2/cnn_v2_static.wgsl
index 7b08132..63fafa8 100644
--- a/workspaces/main/shaders/cnn_v2/cnn_v2_static.wgsl
+++ b/workspaces/main/shaders/cnn_v2/cnn_v2_static.wgsl
@@ -20,6 +20,7 @@ struct StaticFeatureParams {
 @group(0) @binding(3) var depth_tex: texture_2d<f32>;
 @group(0) @binding(4) var output_tex: texture_storage_2d<rgba32uint, write>;
 @group(0) @binding(5) var<uniform> params: StaticFeatureParams;
+@group(0) @binding(6) var linear_sampler: sampler;
 
 @compute @workgroup_size(8, 8)
 fn main(@builtin(global_invocation_id) id: vec3<u32>) {
@@ -30,17 +31,19 @@ fn main(@builtin(global_invocation_id) id: vec3<u32>) {
     return;
   }
 
-  // Parametric features (p0-p3) - sample from specified mip level
+  // Parametric features (p0-p3) - bilinear sample from specified mip level
+  // Use UV coordinates for bilinear interpolation
+  let uv = (vec2<f32>(coord) + 0.5) / vec2<f32>(dims);
   var rgba: vec4<f32>;
   if (params.mip_level == 0u) {
-    rgba = textureLoad(input_tex, coord, 0);
+    rgba = textureSample(input_tex, linear_sampler, uv);
   } else if (params.mip_level == 1u) {
-    rgba = textureLoad(input_tex_mip1, coord, 0);
+    rgba = textureSample(input_tex_mip1, linear_sampler, uv);
   } else if (params.mip_level == 2u) {
-    rgba = textureLoad(input_tex_mip2, coord, 0);
+    rgba = textureSample(input_tex_mip2, linear_sampler, uv);
   } else {
     // Mip 3 or higher: use mip 2 as fallback
-    rgba = textureLoad(input_tex_mip2, coord, 0);
+    rgba = textureSample(input_tex_mip2, linear_sampler, uv);
   }
 
   let p0 = rgba.r;