[11.x] URP Shadergraph Fog Node should return fog intensity as density output

com.unity.render-pipelines.universal/CHANGELOG.md

@@ -61,6 +61,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - 2D shaders now use half-precision floats whenever precise results are not necessary.
 - Removed the ETC1_EXTERNAL_ALPHA variant from Shader Graph Sprite shaders.
 - Eliminated GC allocations caused by the 2D Renderer.
+- Made the density output of Fog Node to be more consistent with how URP mix fog color. This output can be used to mix material color with fog color by using a Lerp Node to lerp between material color and fog color.
 
 ### Fixed
 - Fixed a performance problem with ShaderPreprocessor with large amount of active shader variants in the project 

com.unity.render-pipelines.universal/ShaderLibrary/ShaderGraphFunctions.hlsl

@@ -57,7 +57,7 @@ float3 shadergraph_LWReflectionProbe(float3 viewDir, float3 normalOS, float lod)
 void shadergraph_LWFog(float3 position, out float4 color, out float density)
 {
     color = unity_FogColor;
-    density = ComputeFogFactor(TransformObjectToHClip(position).z);
+    density = ComputeFogIntensity(ComputeFogFactor(TransformObjectToHClip(position).z));
 }
 
 // This function assumes the bitangent flip is encoded in tangentWS.w