Fix cascade blend transition when using an high normal bias

com.unity.render-pipelines.high-definition/CHANGELOG.md

@@ -31,6 +31,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed rasterized accumulation motion blur when DoF is enabled (case 1378497).
 - Fixed light mode not available after switching a light to area "Disc" or "Tube" (case 1372588).
 - Fixed CoC size computation when dynamic resolution is enabled
+- Fixed shadow cascade transition not working properly with bias.
 
 ### Changed
 - Optimizations for the physically based depth of field.

com.unity.render-pipelines.high-definition/Runtime/Lighting/Shadow/HDShadowAlgorithms.hlsl

@@ -265,6 +265,7 @@ float EvalShadow_CascadedDepth_Blend_SplitIndex(HDShadowContext shadowContext, T
         positionWS = basePositionWS + sd.cacheTranslationDelta.xyz;
 
         /* normal based bias */
+        float worldTexelSize = sd.worldTexelSize;
         float3 orig_pos = positionWS;
         float3 normalBias = EvalShadow_NormalBias(sd.worldTexelSize, sd.normalBias, normalWS);
         positionWS += normalBias;
@@ -283,6 +284,11 @@ float EvalShadow_CascadedDepth_Blend_SplitIndex(HDShadowContext shadowContext, T
             if (alpha > 0.0)
             {
                 LoadDirectionalShadowDatas(sd, shadowContext, index + shadowSplitIndex);
+
+                // We need to modify the bias as the world texel size changes between splits and an update is needed.
+                float biasModifier = (sd.worldTexelSize / worldTexelSize);
+                normalBias *= biasModifier;
+
                 float3 evaluationPosWS = basePositionWS + sd.cacheTranslationDelta.xyz + normalBias;
                 float3 posNDC;
                 posTC = EvalShadow_GetTexcoordsAtlas(sd, _CascadeShadowAtlasSize.zw, evaluationPosWS, posNDC, false);