Organize folder structure;

Update RimLighting;

Runtime/Shaders/Includes/Lighting/UtsShadowEvaluation.hlsl

@@ -10,6 +10,53 @@ float3 UtsGetShadowNormal(UtsBSDFData bsdfData)
 #endif
 }
 
+float3 SampleSDFTexture(float3 L, float2 uv, out float angle)
+{
+    float2 right_uv = float2(1 - uv.x, uv.y);
+    float3 left_SDFTex = SAMPLE_TEXTURE2D(_SDFShadingMap, sampler_SDFShadingMap, uv).rgb;
+    float3 right_SDFTex = SAMPLE_TEXTURE2D(_SDFShadingMap, sampler_SDFShadingMap, right_uv).rgb;
+
+    float2 leftVector = normalize(mul(UNITY_MATRIX_M, float4(1.0, 0.0, 0.0, 0.0)).xz);
+    float2 forwardVector = normalize(mul(UNITY_MATRIX_M, float4(0.0, 0.0, 1.0, 0.0)).xz);
+
+    float2 lightDirection = normalize(L.xz);
+    angle = saturate(dot(forwardVector, lightDirection) * -1.0 + _SDFShadowLevel);
+    bool isRightSide = dot(lightDirection, leftVector) > 0;
+    
+    return isRightSide ? right_SDFTex : left_SDFTex;
+}
+
+float GetHairShadow(PositionInputs posInput, float3 L)
+{
+    float shadow = 1.0;
+    
+    // Push the face fragment view space position towards the light for a little bit
+    float hairShadowOpacity = saturate(Remap(length(posInput.positionWS), float2(_HairShadowFadeOutDistance, _HairShadowFadeInDistance), float2(0, 1)));
+    
+    if (hairShadowOpacity > 0.0)
+    {
+        float3 viewLightDir = TransformWorldToViewDir(L); //  / posInput.deviceDepth; when linearDepth grows large, the movement amount should be lower since we are getting further from the face.
+        float3 cameraDirOS = normalize(TransformWorldToObject(GetCameraPositionWS()));
+        float shadowLengthY = _HairShadowDistance * 5.0 * max(0.5, posInput.linearDepth * _HairShadowDistanceScaleFactor) / posInput.linearDepth;
+        float2 shadowLength = float2(shadowLengthY * 2.0f, shadowLengthY);
+    
+        float3 camDirOS = normalize(TransformWorldToObject(GetCameraPositionWS()));
+        float camDirFactor = 1 - smoothstep(0.1, 0.9, camDirOS.y);
+        shadowLength.y *= camDirFactor;
+
+        float2 samplingPoint = (posInput.positionSS + shadowLength * viewLightDir.xy * (_ScreenSize.xy / float2(1920.0f, 1080.0f))) * _ScreenSize.zw; // Use 1080p as the reference resolution to achieve consistent shadow lengths across various screen resolutions.
+
+        // Then sample the hair buffer, to see if the fragment lands in shadow.
+        float2 scaledUVs = samplingPoint * _HairShadowRTHandleScale.xy; // We have to including the scaling factor for our shadow map since we are not going to allocate new texture if the rendering resolution changed.
+        float hairDepth = SAMPLE_TEXTURE2D(_HairShadowTex, s_linear_clamp_sampler, scaledUVs).r;
+        float shadowMask = posInput.deviceDepth <= hairDepth + _HairShadowDepthBias ? 1 : 0; // Hair < Face means Hair are closer to camera 
+        // Note that we have LinearEyeDepth in the buffer. A comparison of depth is needed so that we don't project the shadow of hair behind the face.
+        shadow = lerp(1, 1.0 - hairShadowOpacity, shadowMask);
+    }
+    
+    return shadow;
+}
+
 // distances = {d, d^2, 1/d, d_proj}, where d_proj = dot(lightToSample, light.forward).
 SHADOW_TYPE UtsEvaluateShadow_Punctual(LightLoopContext lightLoopContext, PositionInputs posInput, LightData light, BuiltinData builtinData, float3 N, float3 L, float4 distances)
 {