feat: lighting for rain and snow

package/Shaders/Particle.hlsl

@@ -1,5 +1,6 @@
 #include "Common/FrameBuffer.hlsli"
 #include "Common/VR.hlsli"
+#include "Common/SharedData.hlsli"
 
 struct VS_INPUT
 {
@@ -32,6 +33,7 @@ struct VS_OUTPUT
 	float CullDistance : SV_CullDistance0;  // p11
 	uint EyeIndex : EYEIDX0;
 #endif  // VR
+	float3 ViewPositionVS : TEXCOORD2;
 };
 
 #ifdef VSHADER
@@ -111,6 +113,20 @@ VS_OUTPUT main(VS_INPUT input)
 	vsout.Position.xy = positionOffset + finalViewPosition.xy;
 	vsout.Position.zw = finalViewPosition.zw;
 
+    // Compute view-space for precipitation motion blend
+#	if defined(ENVCUBE)
+#  		if defined(RAIN)
+    float3 viewVS             = mul(WorldView[eyeIndex], msPosition).xyz;
+    float3 adjustedViewVS     = mul(WorldView[eyeIndex], adjustedMsPosition).xyz;
+    float3 finalViewPositionVS = lerp(adjustedViewVS, viewVS, positionBlendParam);
+    vsout.ViewPositionVS = finalViewPositionVS;
+#  		else
+    vsout.ViewPositionVS = mul(WorldView[eyeIndex], msPosition).xyz;
+#  		endif
+#	else
+    vsout.ViewPositionVS = mul(WorldView[eyeIndex], msPosition).xyz;
+#	endif
+
 	vsout.Color.xyz = 1.0.xxx;
 	vsout.Color.w = fVars1.w;
 
@@ -163,6 +179,8 @@ VS_OUTPUT main(VS_INPUT input)
 	vsout.Position.xy = positionOffset * ScaleAdjust + viewPosition.xy;
 	vsout.Position.zw = viewPosition.zw;
 
+    vsout.ViewPositionVS = mul(WorldView[eyeIndex], msPosition).xyz;
+
 	float4 color1, color2;
 	float colorTmp1, colorTmp2;
 	if (tmp1 > fVars1.z) {
@@ -213,6 +231,15 @@ struct PS_OUTPUT
 };
 
 #ifdef PSHADER
+
+#	if defined(LIGHT_LIMIT_FIX)
+#		include "LightLimitFix/LightLimitFix.hlsli"
+#	endif
+
+#	if defined(ISL) && defined(LIGHT_LIMIT_FIX)
+#		include "InverseSquareLighting/InverseSquareLighting.hlsli"
+#	endif
+
 SamplerState SampSourceTexture : register(s0);
 #	if defined(GRAYSCALE_TO_COLOR) || defined(GRAYSCALE_TO_ALPHA)
 SamplerState SampGrayscaleTexture : register(s1);
@@ -273,7 +300,51 @@ PS_OUTPUT main(PS_INPUT input)
 	baseColor.w = grayScaleAlpha;
 #	endif
 
-	psout.Color.xyz = ColorScale * baseColor.xyz;
+	float3 propertyColor = 0.0;
+
+	float3 dirLightColor = SharedData::DirLightColor.xyz * 0.5;
+	float3 ambientColor = max(0, mul(SharedData::DirectionalAmbient, float4(0, 0, 1, 1)).xyz);
+
+	propertyColor += dirLightColor;
+	propertyColor += ambientColor;
+
+	float3 viewPosition = input.ViewPositionVS.xyz;
+	float3 worldPosition = FrameBuffer::ViewToWorld(viewPosition);
+
+#	if defined(LIGHT_LIMIT_FIX)
+	uint lightCount = 0;
+	{
+		float2 screenUV = FrameBuffer::ViewToUV(viewPosition, true, eyeIndex);
+
+		uint clusterIndex = 0;
+		if (LightLimitFix::GetClusterIndex(screenUV, viewPosition.z, clusterIndex)) {
+			lightCount = LightLimitFix::lightGrid[clusterIndex].lightCount;
+			uint lightOffset = LightLimitFix::lightGrid[clusterIndex].offset;
+			[loop] for (uint i = 0; i < lightCount; i++)
+			{
+				uint clusteredLightIndex = LightLimitFix::lightList[lightOffset + i];
+				LightLimitFix::Light light = LightLimitFix::lights[clusteredLightIndex];
+				if (LightLimitFix::IsLightIgnored(light) || light.lightFlags & LightLimitFix::LightFlags::Shadow) {
+					continue;
+				}
+				float3 lightDirection = light.positionWS[eyeIndex].xyz - worldPosition.xyz;
+				float lightDist = length(lightDirection);
+
+#			if defined(ISL)
+				float intensityMultiplier = InverseSquareLighting::GetAttenuation(lightDist, light);
+#			else
+				float intensityFactor = saturate(lightDist / light.radius);
+				float intensityMultiplier = 1 - intensityFactor * intensityFactor;
+#			endif
+
+				float3 lightColor = light.color.xyz * intensityMultiplier * 0.5;
+				propertyColor += lightColor;
+			}
+		}
+	}
+#	endif
+
+	psout.Color.xyz = propertyColor * baseColor.xyz;
 	psout.Color.w = baseColor.w;
 	psout.Normal.w = baseColor.w;
 	psout.Normal.xyz = float3(0, 1, 0);