[HDRP] Fix issue with cloud upscaling

* Fixed perceptual blending when enabling atmospheric scattering.
* Fixed upscaling and reprojection around object borders
* Fixed  upscaling when there is a checkerboard pattern in the depth buffer
* Optimized memory usage when project is using R11G11B10 and anti-ghosting is on
* Enabled anti-ghosting by default
* Optimized depth downsampling + reprojection + upscaling

Checkerboard example: The green object is doing checkerboard fading via shadergraph and is behind behind the clouds, previously you would see it through the clouds
| before | after |
| -- | -- |
| ![image](https://media.github.cds.internal.unity3d.com/user/2154/files/abb9001b-5002-421d-a53f-6aee66af9fce) | ![image](https://media.github.cds.internal.unity3d.com/user/2154/files/5218a853-f6bc-4c90-8cc0-8d1994b7c5e5) |

Author: adrien-de-tocqueville

Packages/com.unity.render-pipelines.core/Runtime/Utilities/CoreUtils.cs

@@ -1148,6 +1148,22 @@ public static void SetKeyword(CommandBuffer cmd, string keyword, bool state)
                 cmd.DisableShaderKeyword(keyword);
         }
 
+        /// <summary>
+        /// Set a local keyword on a ComputeShader using a CommandBuffer
+        /// </summary>
+        /// <param name="cmd">CommandBuffer on which to set the global keyword.</param>
+        /// <param name="cs">Compute Shader on which to set the keyword.</param>
+        /// <param name="keyword">Keyword to be set.</param>
+        /// <param name="state">Value of the keyword to be set.</param>
+        public static void SetKeyword(CommandBuffer cmd, ComputeShader cs, string keyword, bool state)
+        {
+            var kw = new LocalKeyword(cs, keyword);
+            if (state)
+                cmd.EnableKeyword(cs, kw);
+            else
+                cmd.DisableKeyword(cs, kw);
+        }
+
         /// <summary>
         /// Set a global keyword using a RasterCommandBuffer
         /// </summary>
@@ -1162,7 +1178,7 @@ public static void SetKeyword(BaseCommandBuffer cmd, string keyword, bool state)
                 cmd.m_WrappedCommandBuffer.DisableShaderKeyword(keyword);
         }
 
-        // Caution: such a call should not be use interlaced with command buffer command, as it is immediate
+        // Caution: such a call should not be use interleaved with command buffer command, as it is immediate
         /// <summary>
         /// Set a keyword immediately on a Material.
         /// </summary>
@@ -1177,7 +1193,7 @@ public static void SetKeyword(Material material, string keyword, bool state)
                 material.DisableKeyword(keyword);
         }
 
-        // Caution: such a call should not be use interlaced with command buffer command, as it is immediate
+        // Caution: such a call should not be use interleaved with command buffer command, as it is immediate
         /// <summary>
         /// Set a keyword immediately on a Material.
         /// </summary>
@@ -1192,8 +1208,9 @@ public static void SetKeyword(Material material, LocalKeyword keyword, bool stat
                 material.DisableKeyword(keyword);
         }
 
+        // Caution: such a call should not be use interleaved with command buffer command, as it is immediate
         /// <summary>
-        /// Set a keyword to a compute shader
+        /// Set a keyword immediately on a compute shader
         /// </summary>
         /// <param name="cs">Compute Shader on which to set the keyword.</param>
         /// <param name="keyword">Keyword to be set.</param>

Packages/com.unity.render-pipelines.high-definition/Editor/Lighting/VolumetricClouds/VolumetricCloudsEditor.cs

@@ -177,7 +177,7 @@ public override void OnEnable()
         static public readonly GUIContent k_CloudMapTilingText = EditorGUIUtility.TrTextContent("Cloud Map Tiling", "Tiling (x,y) of the cloud map.");
         static public readonly GUIContent k_CloudMapOffsetText = EditorGUIUtility.TrTextContent("Cloud Map Offset", "Offset (x,y) of the cloud map.");
         static public readonly GUIContent k_GlobalHorizontalWindSpeedText = EditorGUIUtility.TrTextContent("Global Horizontal Wind Speed", "Sets the global horizontal wind speed in kilometers per hour.\nThis value can be relative to the Global Wind Speed defined in the Visual Environment.");
-        static public readonly GUIContent k_PerceptualBlending = EditorGUIUtility.TrTextContent("Perceptual Blending", "When enabled, the clouds will blend in a perceptual way with the environment. This may cause artifacts when the sky is over-exposed.");
+        static public readonly GUIContent k_PerceptualBlending = EditorGUIUtility.TrTextContent("Perceptual Blending", "When enabled, the clouds will blend in a perceptual way with the environment. This may cause artifacts when the sky is over-exposed.\nThis only works when MSAA is off.");
 
         void MicroDetailsSection()
         {

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

@@ -231,6 +231,21 @@ public enum VolumetricCloudsDebug
         Depth,
     }
 
+    /// <summary>
+    /// List of Depth Pyramid Full Screen Debug views.
+    /// </summary>
+    public enum DepthPyramidDebugView
+    {
+        /// <summary>
+        /// Closest depth.
+        /// </summary>
+        ClosestDepth,
+        /// <summary>
+        /// Checkerboard of minimum and maximum depth.
+        /// </summary>
+        CheckerboardDepth,
+    }
+
     /// <summary>
     /// Class managing debug display in HDRP.
     /// </summary>
@@ -280,6 +295,8 @@ public partial class DebugData
             public Vector4 fullScreenDebugDepthRemap = new Vector4(0.0f, 1.0f, 0.0f, 0.0f);
             /// <summary>Current full screen debug mode mip level (when applicable).</summary>
             public float fullscreenDebugMip = 0.0f;
+            /// <summary>Enable to show checkerboard depths instead of closest depths (when applicable).</summary>
+            public DepthPyramidDebugView depthPyramidView = DepthPyramidDebugView.ClosestDepth;
             /// <summary>Index of the light used for contact shadows display.</summary>
             public int fullScreenContactShadowLightIndex = 0;
             /// <summary>XR single pass test mode.</summary>
@@ -378,6 +395,7 @@ public partial class DebugData
             internal int lightClusterCategoryDebug;
             internal int historyBufferFrameIndex = 0;
             internal int stpDebugModeEnumIndex;
+            internal int depthPyramidViewEnumIndex;
 
             private float m_DebugGlobalMipBiasOverride = 0.0f;
 
@@ -1246,6 +1264,7 @@ static class LightingStrings
             public static readonly NameAndTooltip FullscreenDebugMode = new() { name = "Fullscreen Debug Mode", tooltip = "Use the drop-down to select a rendering mode to display as an overlay on the screen." };
             public static readonly NameAndTooltip ScreenSpaceShadowIndex = new() { name = "Screen Space Shadow Index", tooltip = "Select the index of the screen space shadows to view with the slider. There must be a Light in the scene that uses Screen Space Shadows." };
             public static readonly NameAndTooltip DepthPyramidDebugMip = new() { name = "Debug Mip", tooltip = "Enable to view a lower-resolution mipmap." };
+            public static readonly NameAndTooltip DepthPyramidDebugView = new() { name = "Debug View", tooltip = "Use the down-down to select which depth pyramid data to show in this view." };
             public static readonly NameAndTooltip DepthPyramidEnableRemap = new() { name = "Enable Depth Remap", tooltip = "Enable remapping of displayed depth values for better vizualization." };
             public static readonly NameAndTooltip DepthPyramidRangeMin = new() { name = "Depth Range Min Value", tooltip = "Distance at which depth values remap starts (0 is near plane, 1 is far plane)" };
             public static readonly NameAndTooltip DepthPyramidRangeMax = new() { name = "Depth Range Max Value", tooltip = "Distance at which depth values remap ends (0 is near plane, 1 is far plane)" };
@@ -1593,6 +1612,16 @@ void RegisterLightingDebug()
                 children =
                 {
                     new DebugUI.FloatField { nameAndTooltip = LightingStrings.DepthPyramidDebugMip, getter = () => data.fullscreenDebugMip, setter = value => data.fullscreenDebugMip = value, min = () => 0f, max = () => 1f, incStep = 0.05f },
+                    new DebugUI.EnumField()
+                    {
+                        isHiddenCallback = () => data.fullScreenDebugMode != FullScreenDebugMode.DepthPyramid,
+                        nameAndTooltip = LightingStrings.DepthPyramidDebugView,
+                        getter = () => (int)data.depthPyramidView,
+                        setter = value => { data.depthPyramidView = (DepthPyramidDebugView)value; },
+                        autoEnum = typeof(DepthPyramidDebugView),
+                        getIndex = () => data.depthPyramidViewEnumIndex,
+                        setIndex = value => { data.depthPyramidViewEnumIndex = value; },
+                    },
                     new DebugUI.BoolField { nameAndTooltip = LightingStrings.DepthPyramidEnableRemap, getter = () => data.enableDebugDepthRemap, setter = value => data.enableDebugDepthRemap = value },
                     new DebugUI.Container()
                     {

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

@@ -16,8 +16,6 @@
 // Local shader variables
 static SHADOW_TYPE g_DebugShadowAttenuation = 0;
 
-StructuredBuffer<int2>  _DebugDepthPyramidOffsets;
-
 #include "Packages/com.unity.render-pipelines.high-definition/Runtime/Debug/PBRValidator.hlsl"
 
 // When displaying lux meter we compress the light in order to be able to display value higher than 65504

Packages/com.unity.render-pipelines.high-definition/Runtime/Debug/DebugFullScreen.shader

@@ -35,7 +35,7 @@ Shader "Hidden/HDRP/DebugFullScreen"
             float _QuadOverdrawMaxQuadCost;
             float _VertexDensityMaxPixelCost;
             uint _DebugContactShadowLightIndex;
-            int _DebugDepthPyramidMip;
+            float4 _DebugDepthPyramidParams; // (mip index, offset_x, offset_y, unused)
             float _MinMotionVector;
             float4 _MotionVecIntensityParams;
             float _FogVolumeOverdrawMaxValue;
@@ -440,11 +440,13 @@ Shader "Hidden/HDRP/DebugFullScreen"
                 }
                 if (_FullScreenDebugMode == FULLSCREENDEBUGMODE_DEPTH_PYRAMID)
                 {
+                    int debugDepthPyramidMip = _DebugDepthPyramidParams.x;
+                    int2 debugDepthPyramidOffset = int2(_DebugDepthPyramidParams.yz);
+
                     // Reuse depth display function from DebugViewMaterial
-                    int2 mipOffset = _DebugDepthPyramidOffsets[_DebugDepthPyramidMip];
-                    uint2 remappedPos = (uint2)(input.texcoord.xy * _DebugViewportSize.xy);
-                    uint2 pixCoord = (uint2)remappedPos.xy >> _DebugDepthPyramidMip;
-                    float depth = LOAD_TEXTURE2D_X(_CameraDepthTexture, pixCoord + mipOffset).r;
+                    uint2 samplePosition = (uint2)((input.texcoord.xy / _RTHandleScale.xy) * _DebugViewportSize.xy);
+                    uint2 pixCoord = (uint2)samplePosition >> debugDepthPyramidMip;
+                    float depth = LOAD_TEXTURE2D_X(_CameraDepthTexture, pixCoord + debugDepthPyramidOffset).r;
                     PositionInputs posInput = GetPositionInput(input.positionCS.xy, _ScreenSize.zw, depth, UNITY_MATRIX_I_VP, UNITY_MATRIX_V);
 
                     // We square the factors to have more precision near zero which is where people usually want to visualize depth.

Packages/com.unity.render-pipelines.high-definition/Runtime/Lighting/ScreenSpaceLighting/BilateralUpsample.hlsl

@@ -86,17 +86,17 @@ float BilUpSingle_Uniform(float HiDepth, float4 LowDepths, float4 lowValue)
 // them in this structure
 struct NeighborhoodUpsampleData3x3
 {
-    // Low resolution depths
+    // Low resolution scene depths
     float4 lowDepthA;
     float4 lowDepthB;
     float lowDepthC;
 
-    // The low resolution masks
-    float4 lowMasksA;
-    float4 lowMasksB;
-    float lowMasksC;
+    // The low resolution depth values
+    float4 lowDepthValueA;
+    float4 lowDepthValueB;
+    float lowDepthValueC;
 
-    // The low resolution values
+    // The low resolution color values
     float4 lowValue0;
     float4 lowValue1;
     float4 lowValue2;
@@ -113,60 +113,10 @@ struct NeighborhoodUpsampleData3x3
     float lowWeightC;
 };
 
-void EvaluateMaskValidity(float linearHighDepth, float lowDepth, int currentIndex,
-                            inout float inputMask, inout int closestNeighhor,
-                            inout float currentDistance)
-{
-    if (inputMask == 0.0f)
-        return;
-
-    // Convert the depths to linear
-    float candidateLinearDepth = Linear01Depth(lowDepth, _ZBufferParams);
-
-    // Compute the distance between the two values
-    float candidateDistance = abs(linearHighDepth - candidateLinearDepth);
-
-    // Evaluate if this becomes the closest neighbor
-    if (candidateDistance < currentDistance)
-    {
-        closestNeighhor = currentIndex;
-        currentDistance = candidateDistance;
-    }
-
-    bool validSample = candidateDistance < (linearHighDepth * 0.3);
-    inputMask = validSample ? 1.0f : 0.0f;
-}
-
-void OverrideMaskValues(float highDepth, inout NeighborhoodUpsampleData3x3 data,
-                        out bool rejectedNeighborhood, out int closestNeighbor)
-{
-    // First of all compute the linear version of the high depth
-    float linearHighDepth = Linear01Depth(highDepth, _ZBufferParams);
-    float currentDistance = 1.0f;
-
-    closestNeighbor = 4; // Index of the closest neighbor (center by default)
-
-    // The center has precedence over the other pixels
-    EvaluateMaskValidity(linearHighDepth, data.lowDepthB.x, 4, data.lowMasksB.x, closestNeighbor, currentDistance);
-
-    // Then the plus
-    EvaluateMaskValidity(linearHighDepth, data.lowDepthA.y, 1, data.lowMasksA.y, closestNeighbor, currentDistance);
-    EvaluateMaskValidity(linearHighDepth, data.lowDepthA.w, 3, data.lowMasksA.w, closestNeighbor, currentDistance);
-    EvaluateMaskValidity(linearHighDepth, data.lowDepthB.y, 5, data.lowMasksB.y, closestNeighbor, currentDistance);
-    EvaluateMaskValidity(linearHighDepth, data.lowDepthB.w, 7, data.lowMasksB.w, closestNeighbor, currentDistance);
-
-    // Then the cross
-    EvaluateMaskValidity(linearHighDepth, data.lowDepthA.x, 0, data.lowMasksA.x, closestNeighbor, currentDistance);
-    EvaluateMaskValidity(linearHighDepth, data.lowDepthA.z, 2, data.lowMasksA.z, closestNeighbor, currentDistance);
-    EvaluateMaskValidity(linearHighDepth, data.lowDepthB.z, 6, data.lowMasksB.z, closestNeighbor, currentDistance);
-    EvaluateMaskValidity(linearHighDepth, data.lowDepthC, 8, data.lowMasksC, closestNeighbor, currentDistance);
-
-    // Flag that tells us which pixel holds valid information
-    rejectedNeighborhood = (currentDistance >= (linearHighDepth * 0.3));
-}
-
 // The bilateral upscale function (3x3 neighborhood)
-float4 BilUpColor3x3(float highDepth, in NeighborhoodUpsampleData3x3 data)
+// Perform joint bilateral upsampling using the scene depth as guide signal
+// https://bartwronski.com/2019/09/22/local-linear-models-guided-filter/
+void BilUpColor3x3(float highDepth, in NeighborhoodUpsampleData3x3 data, out float4 outColor, out float outDepth)
 {
     float4 combinedWeightsA = data.lowWeightA / (abs(highDepth - data.lowDepthA) + _UpsampleTolerance);
     float4 combinedWeightsB = data.lowWeightB / (abs(highDepth - data.lowDepthB) + _UpsampleTolerance);
@@ -186,8 +136,15 @@ float4 BilUpColor3x3(float highDepth, in NeighborhoodUpsampleData3x3 data)
                         + data.lowValue6 * combinedWeightsB.z
                         + data.lowValue7 * combinedWeightsB.w
                         + data.lowValue8 * combinedWeightsC
-                        + float4(_NoiseFilterStrength, _NoiseFilterStrength, _NoiseFilterStrength, 0.0);
-    return WeightedSum / TotalWeight;
+                        + float4(_NoiseFilterStrength.xxx, 0.0f);
+
+    float WeightedDepth = dot(data.lowDepthValueA, combinedWeightsA)
+                        + dot(data.lowDepthValueB, combinedWeightsB)
+                        + data.lowDepthValueC * combinedWeightsC
+                        + _NoiseFilterStrength;
+
+    outColor = WeightedSum / TotalWeight;
+    outDepth = WeightedDepth / TotalWeight;
 }
 
 // Due to compiler issues, it is not possible to use arrays to store the neighborhood values, we then store them in this structure