Fixed the fade in mode of the clouds not impacting the volumetric clouds shadows (case 1381652). #6511

Author: anisunity

TestProjects/HDRP_RuntimeTests/Assets/ReferenceImages/Linear/LinuxPlayer/Vulkan/None/004-CloudsFlaresDecals.png

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed Correlated Color Temperature not being applied in Player builds for Enlighten realtime GI lights (case 1370438);
 - Fixed Normal Map assiignation when importing FBX Materials.
 - Fixed rendering in the editor when an incompatible API is added (case 1384634).
+- Fixed the fade in mode of the clouds not impacting the volumetric clouds shadows (case 1381652).
 
 ## [13.1.4] - 2021-12-04
 

TestProjects/HDRP_RuntimeTests/Assets/ReferenceImages/Linear/WindowsPlayer/Direct3D11/None/004-CloudsFlaresDecals.png

@@ -492,7 +492,7 @@ void UpdateShaderVariableslClouds(ref ShaderVariablesClouds cb, HDCamera hdCamer
                 float groundShadowSize = settings.shadowDistance.value;
 
                 // The world space camera will be required but the global constant buffer will not be injected yet.
-                cb._WorldSpaceShadowCenter = new Vector2(hdCamera.camera.transform.position.x, hdCamera.camera.transform.position.z);
+                cb._WorldSpaceShadowCenter = new Vector4(hdCamera.camera.transform.position.x, hdCamera.camera.transform.position.y, hdCamera.camera.transform.position.z, 0.0f);
 
                 if (HasVolumetricCloudsShadows(hdCamera, settings))
                 {

TestProjects/HDRP_RuntimeTests/Assets/ReferenceImages/Linear/WindowsPlayer/Direct3D12/None/004-CloudsFlaresDecals.png

@@ -1573,7 +1573,7 @@ void ComputeVolumetricCloudsShadow(uint3 currentCoords : SV_DispatchThreadID, ui
 
     // Compute the position of the shadow plane
 #ifdef LOCAL_VOLUMETRIC_CLOUDS
-    float3 shadowCookieCenterWS = float3(_WorldSpaceShadowCenter.x, _ShadowPlaneOffset, _WorldSpaceShadowCenter.y) + t * _SunDirection.xyz;
+    float3 shadowCookieCenterWS = float3(_WorldSpaceShadowCenter.x, _ShadowPlaneOffset, _WorldSpaceShadowCenter.z) + t * _SunDirection.xyz;
 #else
     float3 shadowCookieCenterWS = t * _SunDirection.xyz;
 #endif
@@ -1612,6 +1612,10 @@ void ComputeVolumetricCloudsShadow(uint3 currentCoords : SV_DispatchThreadID, ui
             // Compute the cloud density
             CloudProperties cloudProperties;
             EvaluateCloudProperties(positionWS, 0.0, 0.0, true, true, cloudProperties);
+
+            // Apply the camera fade it to match the clouds perceived by the camera
+            cloudProperties.density = DensityFadeIn(cloudProperties.density, length(positionWS - _WorldSpaceShadowCenter.xyz));
+
             if (cloudProperties.density > CLOUD_DENSITY_TRESHOLD)
             {
                 // Apply the extinction

TestProjects/HDRP_RuntimeTests/Assets/ReferenceImages/Linear/WindowsPlayer/Vulkan/None/004-CloudsFlaresDecals.png

@@ -130,9 +130,10 @@ unsafe struct ShaderVariablesClouds
 
         // The size of the shadow region (meters)
         public Vector2 _ShadowRegionSize;
+        public Vector2 _PaddingVC0;
 
-        // World Camera Position used as the constant buffer has not been injected yet when this data is required
-        public Vector2 _WorldSpaceShadowCenter;
+        // World Camera Position used as the constant buffer has not been injected yet when this data is required, last channel is unused.
+        public Vector4 _WorldSpaceShadowCenter;
 
         // View projection matrix (non oblique) for the planar reflection matrices
         public Matrix4x4 _CameraViewProjection_NO;

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

@@ -61,7 +61,8 @@ CBUFFER_START(ShaderVariablesClouds)
     int _ShadowCookieResolution;
     float _ShadowPlaneOffset;
     float2 _ShadowRegionSize;
-    float2 _WorldSpaceShadowCenter;
+    float2 _PaddingVC0;
+    float4 _WorldSpaceShadowCenter;
     float4x4 _CameraViewProjection_NO;
     float4x4 _CameraInverseViewProjection_NO;
     float4x4 _CameraPrevViewProjection_NO;