From 96a349b9874c6cdaac525ba062a0f4f90c9bc3ed Mon Sep 17 00:00:00 2001
From: skal <pascal.massimino@gmail.com>
Date: Tue, 10 Feb 2026 10:27:44 +0100
Subject: feat: Add coordinate-aware CNN layer 0 for position-dependent
 stylization

- Implement CoordConv2d custom layer accepting (x,y) patch center
- Split layer 0 weights: rgba_weights (9x mat4x4) + coord_weights (mat2x4)
- Add *_with_coord() functions to 3x3/5x5/7x7 convolution shaders
- Update training script to generate coordinate grid and export split weights
- Regenerate placeholder weights with new format

Size impact: +32B coord weights + ~100B shader code = +132B total
All 36 tests passing (100%)

handoff(Claude): CNN coordinate awareness implemented, ready for training

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
---
 workspaces/main/shaders/cnn/cnn_conv7x7.wgsl | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

(limited to 'workspaces/main/shaders/cnn/cnn_conv7x7.wgsl')

diff --git a/workspaces/main/shaders/cnn/cnn_conv7x7.wgsl b/workspaces/main/shaders/cnn/cnn_conv7x7.wgsl
index ba28d64..e68d644 100644
--- a/workspaces/main/shaders/cnn/cnn_conv7x7.wgsl
+++ b/workspaces/main/shaders/cnn/cnn_conv7x7.wgsl
@@ -24,3 +24,30 @@ fn cnn_conv7x7(
 
   return sum;
 }
+
+fn cnn_conv7x7_with_coord(
+  tex: texture_2d<f32>,
+  samp: sampler,
+  uv: vec2<f32>,
+  resolution: vec2<f32>,
+  rgba_weights: array<mat4x4<f32>, 49>,
+  coord_weights: mat2x4<f32>,
+  bias: vec4<f32>
+) -> vec4<f32> {
+  let step = 1.0 / resolution;
+  var sum = bias;
+
+  sum += coord_weights * uv;
+
+  var idx = 0;
+  for (var dy = -3; dy <= 3; dy++) {
+    for (var dx = -3; dx <= 3; dx++) {
+      let offset = vec2<f32>(f32(dx), f32(dy)) * step;
+      let rgba = textureSample(tex, samp, uv + offset);
+      sum += rgba_weights[idx] * rgba;
+      idx++;
+    }
+  }
+
+  return sum;
+}
-- 
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