Fix --mix option: blend prev layer with static p4-p7, not p0-p3

Updated gen_identity_weights.py --mix mode to use static features
p4-p7 (uv_x, uv_y, sin20_y, bias) at channels 8-11 instead of
p0-p3 (RGB+D) at channels 4-7.

Before: 0.5*prev[i] + 0.5*static_p{i} (channels 4-7)
After:  0.5*prev[i] + 0.5*static_p{4+i} (channels 8-11)

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

1 files changed, 7 insertions, 6 deletions

diff --git a/training/gen_identity_weights.py b/training/gen_identity_weights.py
index 5d83bfb..7865d68 100755
--- a/training/gen_identity_weights.py
+++ b/training/gen_identity_weights.py
@@ -4,8 +4,8 @@
 Creates trivial .bin with 1 layer, 1×1 kernel, identity passthrough.
 Output Ch{0,1,2,3} = Input Ch{0,1,2,3} (ignores static features).
 
-With --mix: Output Ch{i} = 0.5*Input Ch{i} + 0.5*Input Ch{i+4}
-  (50-50 blend, avoids overflow)
+With --mix: Output Ch{i} = 0.5*prev[i] + 0.5*static_p{4+i}
+  (50-50 blend of prev layer with uv_x, uv_y, sin20_y, bias)
 
 With --p47: Output Ch{i} = static p{4+i} (uv_x, uv_y, sin20_y, bias)
   (p4/uv_x→ch0, p5/uv_y→ch1, p6/sin20_y→ch2, p7/bias→ch3)
@@ -69,10 +69,11 @@ def generate_identity_weights(output_path, kernel_size=1, mip_level=0, mix=False
         for i in range(out_channels):
             weights[i, i + 8, center, center] = 1.0
     elif mix:
-        # Mix mode: 50-50 blend to avoid overflow
+        # Mix mode: 50-50 blend (p0+p4, p1+p5, p2+p6, p3+p7)
+        # p0-p3 are at channels 0-3 (prev layer), p4-p7 at channels 8-11 (static)
         for i in range(out_channels):
-            weights[i, i, center, center] = 0.5       # 0.5*p{i}
-            weights[i, i + 4, center, center] = 0.5   # 0.5*p{i+4}
+            weights[i, i, center, center] = 0.5       # 0.5*p{i} (prev layer)
+            weights[i, i + 8, center, center] = 0.5   # 0.5*p{i+4} (static)
     else:
         # Identity: output ch i = input ch i
         for i in range(out_channels):
@@ -89,7 +90,7 @@ def generate_identity_weights(output_path, kernel_size=1, mip_level=0, mix=False
     print(f"  Weights: {weight_count}")
     print(f"  Mip level: {mip_level}")
     if mix:
-        print(f"  Mode: 0.5*p0+0.5*p4, 0.5*p1+0.5*p5, 0.5*p2+0.5*p6, 0.5*p3+0.5*p7")
+        print(f"  Mode: 0.5*prev[i] + 0.5*static_p{{4+i}} (blend with uv/sin/bias)")
     elif p47:
         print(f"  Mode: p4→ch0, p5→ch1, p6→ch2, p7→ch3")