Cleaun shader config for shadow (#917)

* Move HDShadowFilteringQuality to main package as it is not used anymore

* Update Upgrading-from-2020.1-to-2020.2.md

Author: sebastienlagarde

com.unity.render-pipelines.high-definition-config/Runtime/ShaderConfig.cs

@@ -4,14 +4,6 @@
 
 namespace UnityEngine.Rendering.HighDefinition
 {
-    [GenerateHLSL(PackingRules.Exact)]
-    public enum HDShadowFilteringQuality
-    {
-        Low = 0,
-        Medium = 1,
-        High = 2,
-    }
-
     [GenerateHLSL(PackingRules.Exact)]
     public enum ProbeVolumesEvaluationModes
     {
@@ -68,9 +60,6 @@ public enum ShaderOptions
 
         AreaLights = 1,
 
-        [System.Obsolete("Deferred shadow can now assume any value, so this field is not used anymore.")]
-        DeferredShadowFiltering = HDShadowFilteringQuality.Medium,
-
         BarnDoor = 0
     };
 
@@ -91,7 +80,5 @@ public class ShaderConfig
         public static ProbeVolumesEncodingModes s_ProbeVolumesEncodingMode = (ProbeVolumesEncodingModes)ShaderOptions.ProbeVolumesEncodingMode;
         public static int s_AreaLights = (int)ShaderOptions.AreaLights;
         public static int s_BarnDoor = (int)ShaderOptions.BarnDoor;
-        [System.Obsolete("Deferred shadow can now assume any value, so this field is not used anymore.")]
-        public static HDShadowFilteringQuality s_DeferredShadowFiltering = (HDShadowFilteringQuality)ShaderOptions.DeferredShadowFiltering;
     }
 }

com.unity.render-pipelines.high-definition/Documentation~/Upgrading-from-2020.1-to-2020.2.md

@@ -37,6 +37,11 @@ HDRP now stores OnEnable and OnDemand shadows in a separate atlas and more API i
 
 The shader function `SampleShadow_PCSS` now requires you to pass in an additional float2 parameter which contains the shadow atlas resolution in x and the inverse of the atlas resolution in y.
 
+## Shader config file
+
+From Unity 2020.2, due to the change of shadow map, the enum HDShadowFilteringQuality have been moved to HDShadowManager.cs and the variables ShaderConfig.s_DeferredShadowFiltering as well as the option ShaderOptions.DeferredShadowFiltering have been removed from the code as they have no impact anymore.
+
+
 ## Shader code
 
 From Unity 2020.2, HDRP uses a new structure to output information from the LightLoop. It now uses a custom LightLoop struct instead of the `float3 diffuseLighting`, `float3 specularLighting` pair. This is to allow HDRP to export more information from the LightLoop in the future without breaking the API.
@@ -88,4 +93,4 @@ With:
 
 ```
 protected override void Execute(CustomPassContext ctx) { ... }
-```
+```

com.unity.render-pipelines.high-definition/Runtime/Lighting/Shadow/HDShadowManager.cs

@@ -5,6 +5,16 @@
 
 namespace UnityEngine.Rendering.HighDefinition
 {
+    /// <summary>
+    /// Shadow Filtering Quality
+    /// </summary>
+    public enum HDShadowFilteringQuality
+    {
+        Low = 0,
+        Medium = 1,
+        High = 2,
+    }
+
     enum ShadowMapType
     {
         CascadedDirectional,