Expose shadow budget parameter in HDRP asset

com.unity.render-pipelines.core/CoreRP/Shadow/ShadowBase.cs

     public class ShadowInitParameters
     {
         public const int kDefaultShadowAtlasSize = 4096;
+        public const int kDefaultMaxPointLightShadows = 6;
+        public const int kDefaultMaxSpotLightShadows = 12;
+        public const int kDefaultMaxDirectionalLightShadows = 1;
+
+        public int      maxPointLightShadows = kDefaultMaxPointLightShadows;
+        public int      maxSpotLightShadows = kDefaultMaxSpotLightShadows;
+        public int      maxDirectionalLightShadows = kDefaultMaxDirectionalLightShadows;
     }
 
     // Class used to pass parameters to the shadow system on a per frame basis.

com.unity.render-pipelines.high-definition/HDRP/Editor/RenderPipeline/Settings/SerializedShadowInitParameters.cs

         public SerializedProperty shadowAtlasWidth;
         public SerializedProperty shadowAtlasHeight;
 
+        public SerializedProperty maxPointLightShadows;
+        public SerializedProperty maxSpotLightShadows;
+        public SerializedProperty maxDirectionalLightShadows;
+
         public SerializedShadowInitParameters(SerializedProperty root)
         {
             this.root = root;
+            maxPointLightShadows = root.Find((ShadowInitParameters s) => s.maxPointLightShadows);
+            maxSpotLightShadows = root.Find((ShadowInitParameters s) => s.maxSpotLightShadows);
+            maxDirectionalLightShadows = root.Find((ShadowInitParameters s) => s.maxDirectionalLightShadows);
         }
     }
 }

com.unity.render-pipelines.high-definition/HDRP/Editor/RenderPipeline/Settings/ShadowInitParametersUI.cs

 using UnityEditor.AnimatedValues;
 using UnityEngine.Events;
 using UnityEngine.Experimental.Rendering.HDPipeline;
+using UnityEngine;
 
 namespace UnityEditor.Experimental.Rendering
 {
 
         static void Drawer_FieldShadowSize(ShadowInitParametersUI s, SerializedShadowInitParameters d, Editor o)
         {
-            EditorGUILayout.LabelField(_.GetContent("Shadow Atlas Settings"), EditorStyles.boldLabel);
+            EditorGUILayout.LabelField(_.GetContent("Shadow"), EditorStyles.boldLabel);
+            
+            ++EditorGUI.indentLevel;
+            EditorGUILayout.LabelField(_.GetContent("Shadow Atlas"), EditorStyles.boldLabel);
+            --EditorGUI.indentLevel;
+
+            EditorGUILayout.Space();
+
+            EditorGUILayout.LabelField(_.GetContent("Shadow Map Budget"), EditorStyles.boldLabel);
+            ++EditorGUI.indentLevel;
+            EditorGUILayout.PropertyField(d.maxPointLightShadows, _.GetContent("Max Point Light Shadows"));
+            EditorGUILayout.PropertyField(d.maxSpotLightShadows, _.GetContent("Max Spot Light Shadows"));
+            EditorGUILayout.PropertyField(d.maxDirectionalLightShadows, _.GetContent("Max Directional Light Shadows"));
+            --EditorGUI.indentLevel;
+
+            // Clamp negative values
+            d.shadowAtlasHeight.intValue = Mathf.Max(0, d.shadowAtlasHeight.intValue);
+            d.shadowAtlasWidth.intValue = Mathf.Max(0, d.shadowAtlasWidth.intValue);
+            d.maxPointLightShadows.intValue = Mathf.Max(0, d.maxPointLightShadows.intValue);
+            d.maxSpotLightShadows.intValue = Mathf.Max(0, d.maxSpotLightShadows.intValue);
+            d.maxDirectionalLightShadows.intValue = Mathf.Max(0, d.maxDirectionalLightShadows.intValue);
+
             --EditorGUI.indentLevel;
         }
     }

com.unity.render-pipelines.high-definition/HDRP/HDRenderPipelineAsset.asset

     enableUltraQualitySSS: 0
     supportVolumetric: 1
     supportRuntimeDebugDisplay: 1
+    supportDitheringCrossFade: 1
     supportDBuffer: 1
     supportMSAA: 0
     msaaSampleCount: 1
     shadowInitParams:
       shadowAtlasWidth: 4096
       shadowAtlasHeight: 4096
+      maxPointLightShadows: 6
+      maxSpotLightShadows: 20
+      maxDirectionalLightShadows: 4
     decalSettings:
       drawDistance: 1000
       atlasWidth: 4096

com.unity.render-pipelines.high-definition/HDRP/Lighting/LightLoop/LightLoop.cs

             scInit.resourceBinder                    = binder;
 
             ShadowManager.ShadowBudgets budgets;
-            budgets.maxPointLights       = 6;
-            budgets.maxSpotLights        = 12;
-            budgets.maxDirectionalLights = 1;
+            budgets.maxPointLights       = shadowInit.maxPointLightShadows;
+            budgets.maxSpotLights        = shadowInit.maxSpotLightShadows;
+            budgets.maxDirectionalLights = shadowInit.maxDirectionalLightShadows;
 
             m_ShadowMgr = new ShadowManager(shadowSettings, ref scInit, ref budgets, m_Shadowmaps);
             // set global overrides - these need to match the override specified in LightLoop/Shadow.hlsl