Grass: light each bush by its own terrain normal again - #28
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ColorByNormalRGBA lived in Render/D3D/D3DRenderTexture.cpp and went out of the build with the D3D9 backend, leaving a no-op that returned 0xffffffff. It is not a D3D function -- it is pure math -- and GrassMap::BuildGrass calls it for real: bush.normal.RGBA() = ColorByNormalRGBA(normal); so every bush on every map got a packed normal of (255,255,255), which grass.vert.hlsl unbiases to (1,1,1) and feeds to ndl = -dot(normal.xyz * 2 - 1, LightDirection.xyz) One constant light term for the whole grass layer, no matter what the blade was standing on. Only the RGB was affected: BuildGrass overwrites normal.a with the blade intensity on the next line, so per-blade brightness was always right. Restores the original body. Verified under lldb against C2_M08 -- the packing matches round((n+1)*127.5) on flat ground (normal (0,0,0.998) -> 0x8080ff) and on slopes ((0.221,0.414,0.883) -> 0x9cb4f0, (0.266,0.452,0.851) -> 0xa1b9ec), and the unpack end is already correct: NORMAL is declared D3DDECLTYPE_D3DCOLOR, the same type as COLOR0, which the shader reads with the same .bgra swizzle and which visibly carries the right terrain colour. The visible change is modest with the sun overhead, which is where C2_M08 starts: light dir (0.069, 0, -0.996) puts flat ground at 0.996 where it used to be 0.927, and a 25-degree slope at 0.864. The error the stub introduced on flat ground is exactly the sun's horizontal component, so it grows toward dawn and dusk. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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