Update TerrainGeometryShader.wgsl

TBD: Texture blending stages work differently in DirectX?

Core/NativeClient/WebGPU/Shaders/TerrainGeometryShader.wgsl

@@ -135,42 +135,47 @@ fn vs_main(in: VertexInput) -> VertexOutput {
 	return out;
 }
 
-// Magenta background pixels should be discarded (but pre-processing on the CPU is expensive)
-fn isTransparentBackgroundPixel(diffuseTextureColor : vec4f) -> bool {
-	return (diffuseTextureColor.r >= 254/255 && diffuseTextureColor.g <= 3/255 && diffuseTextureColor.b >= 254/255);
+fn isTransparentBackgroundPixel(diffuseTextureColor : vec4<f32>) -> bool {
+	return (diffuseTextureColor.r >= 254.0/255.0 && diffuseTextureColor.g <= 3.0/255.0 && diffuseTextureColor.b >= 254.0/255.0);
 }
 
 @fragment
-fn fs_main(in: VertexOutput) -> @location(0) vec4f {
+fn fs_main(in: VertexOutput) -> @location(0) vec4<f32> {
 	let textureCoords = in.diffuseTextureCoords;
 	var diffuseTextureColor = textureSample(diffuseTexture, diffuseTextureSampler, textureCoords);
+
+	if (isTransparentBackgroundPixel(diffuseTextureColor)) {
+		discard;
+	}
+
+	diffuseTextureColor.r *= in.color.r;
+	diffuseTextureColor.g *= in.color.g;
+	diffuseTextureColor.b *= in.color.b;
+	// diffuseTextureColor.a *= in.color.a;
+
 	let normal = normalize(in.surfaceNormal);
 	let sunlightColor = uPerSceneData.directionalLightColor.rgb;
 	let ambientColor = uPerSceneData.ambientLight.rgb;
-
-	if (isTransparentBackgroundPixel(diffuseTextureColor)) {
-		diffuseTextureColor.a = 0.0;
-	}
+	let sunlightRayOrigin = -normalize(uPerSceneData.directionalLightDirection.xyz);
+	let sunlightColorContribution = max(dot(sunlightRayOrigin, normal), 0.0);
+	let directionalLightColor = sunlightColorContribution * sunlightColor;
+	let combinedLightContribution = clampToUnitRange(directionalLightColor + ambientColor);
 
 	let lightmapTexCoords = in.lightmapTextureCoords;
 	var lightmapTextureColor = textureSample(lightmapTexture, lightmapTextureSampler, lightmapTexCoords);
 
-	// Simulated fixed-function pipeline (DirectX7/9) - no specular highlights needed AFAICT?
-	let sunlightRayOrigin = -normalize(uPerSceneData.directionalLightDirection.xyz);
-	let sunlightColorContribution = max(dot(sunlightRayOrigin, normal), 0.0);
-	let directionalLightColor = sunlightColorContribution * sunlightColor;
-	let combinedLightContribution = clampToUnitRange(directionalLightColor + ambientColor) * lightmapTextureColor.a;
+	diffuseTextureColor.r = (diffuseTextureColor.r * lightmapTextureColor.a) + lightmapTextureColor.r;
+	diffuseTextureColor.g = (diffuseTextureColor.g * lightmapTextureColor.a) + lightmapTextureColor.g;
+	diffuseTextureColor.b = (diffuseTextureColor.b * lightmapTextureColor.a) + lightmapTextureColor.b;
+
+	var finalColor = diffuseTextureColor.rgb * combinedLightContribution;
 
-	// Screen blending increases the vibrancy of colors (see https://en.wikipedia.org/wiki/Blend_modes#Screen)
 	let contrastCorrectionColor = clampToUnitRange(ambientColor + sunlightColor - (sunlightColor * ambientColor));
-	let fragmentColor = clampToUnitRange(in.color * contrastCorrectionColor * combinedLightContribution * diffuseTextureColor.rgb + lightmapTextureColor.rgb);
+	finalColor = clampToUnitRange(finalColor * contrastCorrectionColor + lightmapTextureColor.rgb);
 
-	// Should be a no-op if fog is disabled, since the fogFactor would be zero
-	let foggedColor = mix(fragmentColor.rgb, uPerSceneData.fogColor.rgb, in.fogFactor);
+	let foggedColor = mix(finalColor, uPerSceneData.fogColor.rgb, in.fogFactor);
 
-	// Gamma-correction:
-	// WebGPU assumes that the colors output by the fragment shader are given in linear space
-	// When setting the surface format to BGRA8UnormSrgb it performs a linear to sRGB conversion
-	let gammaCorrectedColor = pow(foggedColor.rgb, vec3f(2.2));
-	return vec4f(gammaCorrectedColor, diffuseTextureColor.a + DEBUG_ALPHA_OFFSET);
-}
+	let gammaCorrectedColor = pow(foggedColor, vec3<f32>(2.2));
+
+	return vec4<f32>(gammaCorrectedColor, diffuseTextureColor.a);
+}