Implement mipmap debug mode for terrain.

com.unity.render-pipelines.high-definition/HDRP/Debug/DebugDisplay.cs

             return mipMapDebugSettings.debugMipMapMode;
         }
 
+        public DebugMipMapModeTerrainTexture GetDebugMipMapModeTerrainTexture()
+        {
+            return mipMapDebugSettings.terrainTexture;
+        }
+
         public ColorPickerDebugMode GetDebugColorPickerMode()
         {
             return colorPickerDebugSettings.colorPickerMode;
             widgetList.AddRange(new DebugUI.Widget[]
             {
                 new DebugUI.EnumField { displayName = "Fullscreen Debug Mode", getter = () => (int)fullScreenDebugMode, setter = value => fullScreenDebugMode = (FullScreenDebugMode)value, enumNames = renderingFullScreenDebugStrings, enumValues = renderingFullScreenDebugValues },
-                new DebugUI.EnumField { displayName = "MipMaps", getter = () => (int)mipMapDebugSettings.debugMipMapMode, setter = value => SetMipMapMode((DebugMipMapMode)value), autoEnum = typeof(DebugMipMapMode) },
+                new DebugUI.EnumField { displayName = "MipMaps", getter = () => (int)mipMapDebugSettings.debugMipMapMode, setter = value => SetMipMapMode((DebugMipMapMode)value), autoEnum = typeof(DebugMipMapMode), onValueChanged = RefreshRenderingDebug },
+            });
+            if (mipMapDebugSettings.debugMipMapMode != DebugMipMapMode.None)
+            {
+                widgetList.Add(new DebugUI.Container
+                {
+                    children =
+                    {
+                        new DebugUI.EnumField { displayName = "Terrain Texture", getter = ()=>(int)mipMapDebugSettings.terrainTexture, setter = value => mipMapDebugSettings.terrainTexture = (DebugMipMapModeTerrainTexture)value, autoEnum = typeof(DebugMipMapModeTerrainTexture) }
+                    }
+                });
+            }
+
+            widgetList.AddRange(new []
+            {
                 new DebugUI.Container
                 {
                     displayName = "Color Picker",

com.unity.render-pipelines.high-definition/HDRP/Debug/DebugDisplay.hlsl

 int _DebugLightingSubMode;
 int _DebugViewMaterial; // Contain the id (define in various materialXXX.cs.hlsl) of the property to display
 int _DebugMipMapMode; // Match enum DebugMipMapMode
+int _DebugMipMapModeTerrainTexture; // Match enum DebugMipMapModeTerrainTexture
 int _ColorPickerMode; // Match enum ColorPickerDebugMode
 int _DebugStep;
 float4 _DebugLightingAlbedo; // x == bool override, yzw = albedo for diffuse

com.unity.render-pipelines.high-definition/HDRP/Debug/MipMapDebug.cs

         StreamingMip
     }
 
+    [GenerateHLSL]
+    public enum DebugMipMapModeTerrainTexture
+    {
+        Control,
+        Layer0,
+        Layer1,
+        Layer2,
+        Layer3,
+        Layer4,
+        Layer5,
+        Layer6,
+        Layer7
+    }
+
+        public DebugMipMapModeTerrainTexture terrainTexture = DebugMipMapModeTerrainTexture.Control;
 
         public bool IsDebugDisplayEnabled()
         {

com.unity.render-pipelines.high-definition/HDRP/Debug/MipMapDebug.cs.hlsl

 #define DEBUGMIPMAPMODE_STREAMING_MIP_BUDGET (4)
 #define DEBUGMIPMAPMODE_STREAMING_MIP (5)
 
+//
+// UnityEngine.Experimental.Rendering.HDPipeline.DebugMipMapModeTerrainTexture:  static fields
+//
+#define DEBUGMIPMAPMODETERRAINTEXTURE_CONTROL (0)
+#define DEBUGMIPMAPMODETERRAINTEXTURE_LAYER0 (1)
+#define DEBUGMIPMAPMODETERRAINTEXTURE_LAYER1 (2)
+#define DEBUGMIPMAPMODETERRAINTEXTURE_LAYER2 (3)
+#define DEBUGMIPMAPMODETERRAINTEXTURE_LAYER3 (4)
+#define DEBUGMIPMAPMODETERRAINTEXTURE_LAYER4 (5)
+#define DEBUGMIPMAPMODETERRAINTEXTURE_LAYER5 (6)
+#define DEBUGMIPMAPMODETERRAINTEXTURE_LAYER6 (7)
+#define DEBUGMIPMAPMODETERRAINTEXTURE_LAYER7 (8)
+
 
 #endif

com.unity.render-pipelines.high-definition/HDRP/Material/TerrainLit/TerrainLitData.hlsl

     AddDecalContribution(posInput, surfaceData, alpha);
 #endif
 
-#if defined(DEBUG_DISPLAY)
+#ifdef DEBUG_DISPLAY
-        // TODO: uncomment and fix me.
-        surfaceData.baseColor = 1;
-        // surfaceData.baseColor = GetTextureDataDebug(_DebugMipMapMode, input.texCoord0, _BaseColorMap0, _BaseColorMap0_TexelSize, _BaseColorMap0_MipInfo, surfaceData.baseColor);
+        if (_DebugMipMapModeTerrainTexture == DEBUGMIPMAPMODETERRAINTEXTURE_CONTROL)
+            surfaceData.baseColor = GetTextureDataDebug(_DebugMipMapMode, input.texCoord0, _Control0, _Control0_TexelSize, _Control0_MipInfo, surfaceData.baseColor);
+        else if (_DebugMipMapModeTerrainTexture == DEBUGMIPMAPMODETERRAINTEXTURE_LAYER0)
+            surfaceData.baseColor = GetTextureDataDebug(_DebugMipMapMode, input.texCoord0 * _Splat0_ST.xy + _Splat0_ST.zw, _Splat0, _Splat0_TexelSize, _Splat0_MipInfo, surfaceData.baseColor);
+        else if (_DebugMipMapModeTerrainTexture == DEBUGMIPMAPMODETERRAINTEXTURE_LAYER1)
+            surfaceData.baseColor = GetTextureDataDebug(_DebugMipMapMode, input.texCoord0 * _Splat1_ST.xy + _Splat1_ST.zw, _Splat1, _Splat1_TexelSize, _Splat1_MipInfo, surfaceData.baseColor);
+        else if (_DebugMipMapModeTerrainTexture == DEBUGMIPMAPMODETERRAINTEXTURE_LAYER2)
+            surfaceData.baseColor = GetTextureDataDebug(_DebugMipMapMode, input.texCoord0 * _Splat2_ST.xy + _Splat2_ST.zw, _Splat2, _Splat2_TexelSize, _Splat2_MipInfo, surfaceData.baseColor);
+        else if (_DebugMipMapModeTerrainTexture == DEBUGMIPMAPMODETERRAINTEXTURE_LAYER3)
+            surfaceData.baseColor = GetTextureDataDebug(_DebugMipMapMode, input.texCoord0 * _Splat3_ST.xy + _Splat3_ST.zw, _Splat3, _Splat3_TexelSize, _Splat3_MipInfo, surfaceData.baseColor);
+    #ifdef _TERRAIN_8_LAYERS
+        else if (_DebugMipMapModeTerrainTexture == DEBUGMIPMAPMODETERRAINTEXTURE_LAYER4)
+            surfaceData.baseColor = GetTextureDataDebug(_DebugMipMapMode, input.texCoord0 * _Splat4_ST.xy + _Splat4_ST.zw, _Splat4, _Splat4_TexelSize, _Splat4_MipInfo, surfaceData.baseColor);
+        else if (_DebugMipMapModeTerrainTexture == DEBUGMIPMAPMODETERRAINTEXTURE_LAYER5)
+            surfaceData.baseColor = GetTextureDataDebug(_DebugMipMapMode, input.texCoord0 * _Splat5_ST.xy + _Splat5_ST.zw, _Splat5, _Splat5_TexelSize, _Splat5_MipInfo, surfaceData.baseColor);
+        else if (_DebugMipMapModeTerrainTexture == DEBUGMIPMAPMODETERRAINTEXTURE_LAYER6)
+            surfaceData.baseColor = GetTextureDataDebug(_DebugMipMapMode, input.texCoord0 * _Splat6_ST.xy + _Splat6_ST.zw, _Splat6, _Splat6_TexelSize, _Splat6_MipInfo, surfaceData.baseColor);
+        else if (_DebugMipMapModeTerrainTexture == DEBUGMIPMAPMODETERRAINTEXTURE_LAYER7)
+            surfaceData.baseColor = GetTextureDataDebug(_DebugMipMapMode, input.texCoord0 * _Splat7_ST.xy + _Splat7_ST.zw, _Splat7, _Splat7_TexelSize, _Splat7_MipInfo, surfaceData.baseColor);
+    #endif
         surfaceData.metallic = 0;
     }
 #endif

com.unity.render-pipelines.high-definition/HDRP/Material/TerrainLit/TerrainLitData_Basemap.hlsl

 
 #include "TerrainLitSplatCommon.hlsl"
 
+TEXTURE2D(_MainTex);
+TEXTURE2D(_MetallicTex);
+SAMPLER(sampler_MainTex);
+
+#ifdef DEBUG_DISPLAY
+float4 _MainTex_TexelSize;
+float4 _MainTex_MipInfo;
+#endif
+
 // We don't use emission for terrain
 #define _EmissiveColor float3(0,0,0)
 #define _AlbedoAffectEmissive 0
     AddDecalContribution(posInput, surfaceData, alpha);
 #endif
 
-#if defined(DEBUG_DISPLAY)
+#ifdef DEBUG_DISPLAY
-        // TODO: uncomment and fix me.
-        surfaceData.baseColor = 1;
-        // surfaceData.baseColor = GetTextureDataDebug(_DebugMipMapMode, input.texCoord0, _BaseColorMap0, _BaseColorMap0_TexelSize, _BaseColorMap0_MipInfo, surfaceData.baseColor);
+        surfaceData.baseColor = GetTextureDataDebug(_DebugMipMapMode, input.texCoord0, _MainTex, _MainTex_TexelSize, _MainTex_MipInfo, surfaceData.baseColor);
         surfaceData.metallic = 0;
     }
 #endif

com.unity.render-pipelines.high-definition/HDRP/Material/TerrainLit/TerrainLitSplatCommon.hlsl

 TEXTURE2D(_Control0);
 SAMPLER(sampler_Splat0);
 SAMPLER(sampler_Control0);
-TEXTURE2D(_MainTex);
-TEXTURE2D(_MetallicTex);
-SAMPLER(sampler_MainTex);
 
 #ifdef UNITY_INSTANCING_ENABLED
 TEXTURE2D(_TerrainHeightmapTexture);
     float4 _MaskMapRemapOffset##n;      \
     float4 _MaskMapRemapScale##n
 
-CBUFFER_START(UnityPerMaterial)
+CBUFFER_START(UnityTerrain)
+
+    #ifdef DEBUG_DISPLAY
+        float4 _Control0_TexelSize;
+        float4 _Control0_MipInfo;
+        float4 _Splat0_TexelSize;
+        float4 _Splat0_MipInfo;
+        float4 _Splat1_TexelSize;
+        float4 _Splat1_MipInfo;
+        float4 _Splat2_TexelSize;
+        float4 _Splat2_MipInfo;
+        float4 _Splat3_TexelSize;
+        float4 _Splat3_MipInfo;
+        #ifdef _TERRAIN_8_LAYERS
+            float4 _Splat4_TexelSize;
+            float4 _Splat4_MipInfo;
+            float4 _Splat5_TexelSize;
+            float4 _Splat5_MipInfo;
+            float4 _Splat6_TexelSize;
+            float4 _Splat6_MipInfo;
+            float4 _Splat7_TexelSize;
+            float4 _Splat7_MipInfo;
+        #endif
+    #endif
 
     DECLARE_TERRAIN_LAYER_PROPS(0);
     DECLARE_TERRAIN_LAYER_PROPS(1);
     #endif
 
     float _HeightTransition;
-    float4 _TerrainHeightmapRecipSize;   // float4(1.0f/width, 1.0f/height, 1.0f/(width-1), 1.0f/(height-1))
-    float4 _TerrainHeightmapScale;       // float4(hmScale.x, hmScale.y / (float)(kMaxHeight), hmScale.z, 0.0f)
+    #ifdef UNITY_INSTANCING_ENABLED
+        float4 _TerrainHeightmapRecipSize;   // float4(1.0f/width, 1.0f/height, 1.0f/(width-1), 1.0f/(height-1))
+        float4 _TerrainHeightmapScale;       // float4(hmScale.x, hmScale.y / (float)(kMaxHeight), hmScale.z, 0.0f)
+    #endif
 
 CBUFFER_END
 

com.unity.render-pipelines.high-definition/HDRP/RenderPipeline/HDRenderPipeline.cs

                 cmd.SetGlobalInt(HDShaderIDs._DebugLightingMode, (int)m_CurrentDebugDisplaySettings.GetDebugLightingMode());
                 cmd.SetGlobalInt(HDShaderIDs._DebugLightingSubMode, (int)m_CurrentDebugDisplaySettings.GetDebugLightingSubMode());
                 cmd.SetGlobalInt(HDShaderIDs._DebugMipMapMode, (int)m_CurrentDebugDisplaySettings.GetDebugMipMapMode());
+                cmd.SetGlobalInt(HDShaderIDs._DebugMipMapModeTerrainTexture, (int)m_CurrentDebugDisplaySettings.GetDebugMipMapModeTerrainTexture());
                 cmd.SetGlobalInt(HDShaderIDs._ColorPickerMode, (int)m_CurrentDebugDisplaySettings.GetDebugColorPickerMode());
 
                 cmd.SetGlobalVector(HDShaderIDs._DebugLightingAlbedo, debugAlbedo);

com.unity.render-pipelines.high-definition/HDRP/RenderPipeline/HDStringConstants.cs

         public static readonly int _DebugLightingSpecularColor = Shader.PropertyToID("_DebugLightingSpecularColor");
         public static readonly int _AmbientOcclusionTexture = Shader.PropertyToID("_AmbientOcclusionTexture");
         public static readonly int _DebugMipMapMode = Shader.PropertyToID("_DebugMipMapMode");
+        public static readonly int _DebugMipMapModeTerrainTexture = Shader.PropertyToID("_DebugMipMapModeTerrainTexture");
 
         public static readonly int _UseTileLightList = Shader.PropertyToID("_UseTileLightList");