Hd/fix backplate globalcubemap2 (#3111)

* Removed backplate from rendering of lighting cubemap as it did not really work conceptually and caused artefacts.

* Update changelog

* Remove useless code

* Compilation fix.

* Update doc

* Update Override-HDRI-Sky.md

Co-authored-by: sebastienlagarde <sebastien@unity3d.com>

com.unity.render-pipelines.high-definition/CHANGELOG.md

@@ -91,6 +91,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Changed the clamping approach for RTR and RTGI (in both perf and quality) to improve visual quality.
 - Changed the warning message for ray traced area shadows (case 1303410).
 - Disabled specular occlusion for what we consider medium and larger scale ao > 1.25 with a 25cm falloff interval.
+- Removed backplate from rendering of lighting cubemap as it did not really work conceptually and caused artefacts.
 
 ## [10.3.0] - 2020-12-01
 

com.unity.render-pipelines.high-definition/Documentation~/Override-HDRI-Sky.md

@@ -65,4 +65,6 @@ These properties only appear if you enable [more options](More-Options.md).
 | -**Shadow Tint** | Specifies the color to tint shadows cast onto the backplate. |
 | - **Reset Color** | Resets the saved **Shadow Tint** for the shadow. HDRP calculates a new default shadow tint when the HDRI changes. |
 
-**Note**: To use ambient occlusion in the backplate, increase the value of the **Direct Lighting Strength** property on the [Ambient Occlusion](Override-Ambient-Occlusion.md) component override. As the backplate does not have global illumination, it can only get ambient occlusion from direct lighting.
+**Note**: To use ambient occlusion in the backplate, increase the value of the **Direct Lighting Strength** property on the [Ambient Occlusion](Override-Ambient-Occlusion.md) component override. As the backplate does not have global illumination, it can only get ambient occlusion from direct lighting. 
+
+**Limitation**: The backplate don't affect the Sky lighting (Sky Reflection / Ligthmaps / LightProbes / Ambient Probe). It will not appear with the default sky reflection but only in local reflection probes.

com.unity.render-pipelines.high-definition/Runtime/Sky/HDRISky/HDRISky.shader

@@ -310,11 +310,6 @@ Shader "Hidden/HDRP/Sky/HDRISky"
         return results;
     }
 
-    float4 FragBakingBackplate(Varyings input) : SV_Target
-    {
-        return RenderBackplate(input, 1.0);
-    }
-
     float4 FragRenderBackplate(Varyings input) : SV_Target
     {
         UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(input);
@@ -338,12 +333,6 @@ Shader "Hidden/HDRP/Sky/HDRISky"
         return depth;
     }
 
-    float FragBakingBackplateDepth(Varyings input) : SV_Depth
-    {
-        UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(input);
-        return GetDepthWithBackplate(input);
-    }
-
     float4 FragRenderBackplateDepth(Varyings input, out float depth : SV_Depth) : SV_Target0
     {
         UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(input);
@@ -392,20 +381,6 @@ Shader "Hidden/HDRP/Sky/HDRISky"
             ENDHLSL
         }
 
-        // HDRI Sky with Backplate
-        // For cubemap with Backplate
-        Pass
-        {
-            ZWrite Off
-            ZTest Always
-            Blend Off
-            Cull Off
-
-            HLSLPROGRAM
-                #pragma fragment FragBakingBackplate
-            ENDHLSL
-        }
-
         // For fullscreen Sky with Backplate
         Pass
         {
@@ -419,20 +394,6 @@ Shader "Hidden/HDRP/Sky/HDRISky"
             ENDHLSL
         }
 
-        // HDRI Sky with Backplate for PreRenderSky (Depth Only Pass)
-        // DepthOnly For cubemap with Backplate
-        Pass
-        {
-            ZWrite On
-            ZTest LEqual
-            Blend Off
-            Cull Off
-
-            HLSLPROGRAM
-                #pragma fragment FragBakingBackplateDepth
-            ENDHLSL
-        }
-
         // DepthOnly For fullscreen Sky with Backplate
         Pass
         {

com.unity.render-pipelines.high-definition/Runtime/Sky/HDRISky/HDRISkyRenderer.cs

@@ -13,10 +13,8 @@ class HDRISkyRenderer : SkyRenderer
 
         private static int m_RenderCubemapID                                = 0; // FragBaking
         private static int m_RenderFullscreenSkyID                          = 1; // FragRender
-        private static int m_RenderCubemapWithBackplateID                   = 2; // FragBakingBackplate
-        private static int m_RenderFullscreenSkyWithBackplateID             = 3; // FragRenderBackplate
-        private static int m_RenderDepthOnlyCubemapWithBackplateID          = 4; // FragBakingBackplateDepth
-        private static int m_RenderDepthOnlyFullscreenSkyWithBackplateID    = 5; // FragRenderBackplateDepth
+        private static int m_RenderFullscreenSkyWithBackplateID             = 2; // FragRenderBackplate
+        private static int m_RenderDepthOnlyFullscreenSkyWithBackplateID    = 3; // FragRenderBackplateDepth
 
         public HDRISkyRenderer()
         {
@@ -92,16 +90,10 @@ public override bool RequiresPreRenderSky(BuiltinSkyParameters builtinParams)
             return hdriSky.enableBackplate.value;
         }
 
-        public override void PreRenderSky(BuiltinSkyParameters builtinParams, bool renderForCubemap, bool renderSunDisk)
+        public override void PreRenderSky(BuiltinSkyParameters builtinParams)
         {
             var hdriSky = builtinParams.skySettings as HDRISky;
 
-            int passID;
-            if (renderForCubemap)
-                passID = m_RenderDepthOnlyCubemapWithBackplateID;
-            else
-                passID = m_RenderDepthOnlyFullscreenSkyWithBackplateID;
-
             float intensity, phi, backplatePhi;
             GetParameters(out intensity, out phi, out backplatePhi, builtinParams, hdriSky);
 
@@ -113,7 +105,7 @@ public override void PreRenderSky(BuiltinSkyParameters builtinParams, bool rende
 
                 m_PropertyBlock.SetMatrix(HDShaderIDs._PixelCoordToViewDirWS, builtinParams.pixelCoordToViewDirMatrix);
 
-                CoreUtils.DrawFullScreen(builtinParams.commandBuffer, m_SkyHDRIMaterial, m_PropertyBlock, passID);
+                CoreUtils.DrawFullScreen(builtinParams.commandBuffer, m_SkyHDRIMaterial, m_PropertyBlock, m_RenderDepthOnlyFullscreenSkyWithBackplateID);
             }
         }
 
@@ -123,19 +115,20 @@ public override void RenderSky(BuiltinSkyParameters builtinParams, bool renderFo
             float intensity, phi, backplatePhi;
             GetParameters(out intensity, out phi, out backplatePhi, builtinParams, hdriSky);
             int passID;
-            if (hdriSky.enableBackplate.value == false)
+            if (renderForCubemap)
             {
-                if (renderForCubemap)
-                    passID = m_RenderCubemapID;
-                else
-                    passID = m_RenderFullscreenSkyID;
+                passID = m_RenderCubemapID;
             }
             else
             {
-                if (renderForCubemap)
-                    passID = m_RenderCubemapWithBackplateID;
+                if (hdriSky.enableBackplate.value == false)
+                {
+                    passID = m_RenderFullscreenSkyID;
+                }
                 else
+                {
                     passID = m_RenderFullscreenSkyWithBackplateID;
+                }
             }
 
             if (hdriSky.enableDistortion.value == true)
@@ -182,6 +175,7 @@ public override void RenderSky(BuiltinSkyParameters builtinParams, bool renderFo
                 shadowFilter |= unchecked((uint)LightFeatureFlags.Area);
             m_SkyHDRIMaterial.SetInt(HDShaderIDs._BackplateShadowFilter, unchecked((int)shadowFilter));
 
+
             // This matrix needs to be updated at the draw call frequency.
             m_PropertyBlock.SetMatrix(HDShaderIDs._PixelCoordToViewDirWS, builtinParams.pixelCoordToViewDirMatrix);
             CoreUtils.DrawFullScreen(builtinParams.commandBuffer, m_SkyHDRIMaterial, m_PropertyBlock, passID);

com.unity.render-pipelines.high-definition/Runtime/Sky/SkyManager.cs

@@ -325,8 +325,6 @@ public void Build(HDRenderPipelineAsset hdAsset, RenderPipelineResources default
             m_SkyboxBSDFCubemapIntermediate = RTHandles.Alloc(resolution, resolution, colorFormat: GraphicsFormat.R16G16B16A16_SFloat, dimension: TextureDimension.Cube, useMipMap: true, autoGenerateMips: false, filterMode: FilterMode.Trilinear, name: "SkyboxBSDFIntermediate");
             m_CubemapScreenSize = new Vector4((float)resolution, (float)resolution, 1.0f / (float)resolution, 1.0f / (float)resolution);
 
-            var cubeProj = Matrix4x4.Perspective(90.0f, 1.0f, 0.01f, 1.0f);
-
             for (int i = 0; i < 6; ++i)
             {
                 var lookAt = Matrix4x4.LookAt(Vector3.zero, CoreUtils.lookAtList[i], CoreUtils.upVectorList[i]);
@@ -962,7 +960,7 @@ public void PreRenderSky(HDCamera hdCamera, Light sunLight, RTHandle colorBuffer
                 }
 
                 if (preRenderSky)
-                    skyContext.skyRenderer.PreRenderSky(m_BuiltinParameters, false, hdCamera.camera.cameraType != CameraType.Reflection || skyContext.skySettings.includeSunInBaking.value);
+                    skyContext.skyRenderer.PreRenderSky(m_BuiltinParameters);
 
                 if (skyContext.HasClouds() && skyContext.cloudRenderer.RequiresPreRenderClouds(m_BuiltinParameters))
                 {

com.unity.render-pipelines.high-definition/Runtime/Sky/SkyRenderer.cs

@@ -33,7 +33,18 @@ public abstract class SkyRenderer
         /// <param name="builtinParams">Engine parameters that you can use to render the sky.</param>
         /// <param name="renderForCubemap">Pass in true if you want to render the sky into a cubemap for lighting. This is useful when the sky renderer needs a different implementation in this case.</param>
         /// <param name="renderSunDisk">If the sky renderer supports the rendering of a sun disk, it must not render it if this is set to false.</param>
-        public virtual void PreRenderSky(BuiltinSkyParameters builtinParams, bool renderForCubemap, bool renderSunDisk) {}
+        [System.Obsolete("Please override PreRenderSky(BuiltinSkyParameters) instead.")]
+        public virtual void PreRenderSky(BuiltinSkyParameters builtinParams, bool renderForCubemap, bool renderSunDisk)
+        {
+            PreRenderSky(builtinParams);
+        }
+
+        /// <summary>
+        /// Preprocess for rendering the sky. Called before the DepthPrePass operations
+        /// </summary>
+        /// <param name="builtinParams">Engine parameters that you can use to render the sky.</param>
+        public virtual void PreRenderSky(BuiltinSkyParameters builtinParams) {}
+
 
         /// <summary>
         /// Whether the PreRenderSky step is required.