Updated namespace;

Added UTSPass;
Chnaged the RTHanlde _HairShadowMap to not reallocate when screen resolution decreased;

Runtime/HDRP/Shaders/ShaderPassForwardUTS.hlsl

@@ -910,7 +910,7 @@ void Frag(PackedVaryingsToPS packedInput,
     utsAggregateLighting.directSpecular += _SDFNoseHighlightCoef * SDFNoseHighlight(angle, sdfRes.g, rightside, SDF_UV) * lightColor;
 #endif
 
-#if defined(_RECEIVE_HAIR_SHADOW) && defined(_HAIR_SHADOWS)
+#ifdef _RECEIVE_HAIR_SHADOW
     // 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)));
     
@@ -924,8 +924,8 @@ void Frag(PackedVaryingsToPS packedInput,
         float2 samplingPoint = (input.positionSS.xy + 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.
-        float4 hairBuffer = SAMPLE_TEXTURE2D(_HairShadowTex, s_trilinear_clamp_sampler, samplingPoint);
-        float hairDepth = hairBuffer.r;
+        float2 scaledUVs = samplingPoint * _HairShadowRTHandleScale; // 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_trilinear_clamp_sampler, scaledUVs).r;
         float depthCorrect = 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.
         float hairShadow = lerp(0,hairShadowOpacity,depthCorrect);