Fixed gaussian pyramid first blit (point -> bilinear filtering)

Should look smoother and reduce aliasing in motion.

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/HDAssetFactory.cs

 
                 // General
                 newAsset.cameraMotionVectors = Load<Shader>(HDRenderPipelinePath + "RenderPipelineResources/CameraMotionVectors.shader");
-                newAsset.copyStencilBuffer = Load<Shader>(HDRenderPipelinePath + "RenderPipelineResources/copyStencilBuffer.shader");
+                newAsset.copyStencilBuffer = Load<Shader>(HDRenderPipelinePath + "RenderPipelineResources/CopyStencilBuffer.shader");
+                newAsset.blit = Load<Shader>(HDRenderPipelinePath + "RenderPipelineResources/Blit.shader");
 
                 // Sky
                 newAsset.blitCubemap = Load<Shader>(HDRenderPipelinePath + "Sky/BlitCubemap.shader");

ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDRenderPipeline.cs

         Material m_currentDebugViewMaterialGBuffer;
         Material m_DebugDisplayLatlong;
         Material m_DebugFullScreen;
+        Material m_Blit;
         Material m_ErrorMaterial;
 
         // Various buffer
             m_DebugViewMaterialGBufferShadowMask.EnableKeyword("SHADOWS_SHADOWMASK");
             m_DebugDisplayLatlong = CoreUtils.CreateEngineMaterial(m_Asset.renderPipelineResources.debugDisplayLatlongShader);
             m_DebugFullScreen = CoreUtils.CreateEngineMaterial(m_Asset.renderPipelineResources.debugFullScreenShader);
+            m_Blit = CoreUtils.CreateEngineMaterial(m_Asset.renderPipelineResources.blit);
             m_ErrorMaterial = CoreUtils.CreateEngineMaterial("Hidden/InternalErrorShader");
         }
 
             CoreUtils.Destroy(m_DebugViewMaterialGBufferShadowMask);
             CoreUtils.Destroy(m_DebugDisplayLatlong);
             CoreUtils.Destroy(m_DebugFullScreen);
+            CoreUtils.Destroy(m_Blit);
             CoreUtils.Destroy(m_ErrorMaterial);
 
             m_SSSBufferManager.Cleanup();
 
                 cmd.SetGlobalVector(HDShaderIDs._GaussianPyramidColorMipSize, new Vector4(pyramidSideSize, pyramidSideSize, lodCount, 0));
 
-                cmd.Blit(m_CameraColorBufferRT, m_GaussianPyramidColorBufferRT);
+                cmd.SetGlobalTexture(HDShaderIDs._BlitTexture, m_CameraColorBufferRT);
+                CoreUtils.DrawFullScreen(cmd, m_Blit, m_GaussianPyramidColorBufferRT, null, 1); // Bilinear filtering
 
                 var last = m_GaussianPyramidColorBuffer;
 

ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDStringConstants.cs

             Shader.PropertyToID("_DepthPyramidMip14"),
         };
         public static readonly int _DebugFullScreenTexture = Shader.PropertyToID("_DebugFullScreenTexture");
+        public static readonly int _BlitTexture = Shader.PropertyToID("_BlitTexture");
 
         public static readonly int _WorldScales = Shader.PropertyToID("_WorldScales");
         public static readonly int _FilterKernels = Shader.PropertyToID("_FilterKernels");

ScriptableRenderPipeline/HDRenderPipeline/HDRP/RenderPipelineResources/HDRenderPipelineResources.asset

   combineLighting: {fileID: 4800000, guid: 2e37131331fbdca449b1a2bc47a639ca, type: 3}
   cameraMotionVectors: {fileID: 4800000, guid: 035941b63024d1943af48811c1db20d9, type: 3}
   copyStencilBuffer: {fileID: 4800000, guid: 3d1574f1cdfa0ce4995f9bc79ed7f8ec, type: 3}
+  blit: {fileID: 4800000, guid: 370f7a9cc4e362d488af024d371091e8, type: 3}
   blitCubemap: {fileID: 4800000, guid: d05913e251bed7a4992c921c62e1b647, type: 3}
   buildProbabilityTables: {fileID: 7200000, guid: b9f26cf340afe9145a699753531b2a4c,
     type: 3}

ScriptableRenderPipeline/HDRenderPipeline/HDRP/RenderPipelineResources/RenderPipelineResources.cs

         // General
         public Shader cameraMotionVectors;
         public Shader copyStencilBuffer;
+        public Shader blit;
 
         // Sky
         public Shader blitCubemap;

ScriptableRenderPipeline/HDRenderPipeline/HDRP/RenderPipelineResources/Blit.shader

+Shader "Hidden/HDRenderPipeline/Blit"
+{
+    HLSLINCLUDE
+
+        #pragma target 4.5
+        #pragma only_renderers d3d11 ps4 xboxone vulkan metal
+        #include "CoreRP/ShaderLibrary/Common.hlsl"
+        #include "../ShaderVariables.hlsl"
+
+        TEXTURE2D(_BlitTexture);
+        SamplerState sampler_PointClamp;
+        SamplerState sampler_LinearClamp;
+
+        struct Attributes
+        {
+            uint vertexID : SV_VertexID;
+        };
+
+        struct Varyings
+        {
+            float4 positionCS : SV_POSITION;
+            float2 texcoord   : TEXCOORD0;
+        };
+
+        Varyings Vert(Attributes input)
+        {
+            Varyings output;
+            output.positionCS = GetFullScreenTriangleVertexPosition(input.vertexID);
+            output.texcoord   = GetFullScreenTriangleTexCoord(input.vertexID);
+            return output;
+        }
+
+        float4 FragNearest(Varyings input) : SV_Target
+        {
+            return SAMPLE_TEXTURE2D(_BlitTexture, sampler_PointClamp, input.texcoord);
+        }
+
+        float4 FragBilinear(Varyings input) : SV_Target
+        {
+            return SAMPLE_TEXTURE2D(_BlitTexture, sampler_LinearClamp, input.texcoord);
+        }
+
+    ENDHLSL
+
+    SubShader
+    {
+        // 0: Nearest
+        Pass
+        {
+            ZWrite Off ZTest Always Blend Off Cull Off
+
+            HLSLPROGRAM
+                #pragma vertex Vert
+                #pragma fragment FragNearest
+            ENDHLSL
+        }
+
+        // 1: Bilinear
+        Pass
+        {
+            ZWrite Off ZTest Always Blend Off Cull Off
+
+            HLSLPROGRAM
+                #pragma vertex Vert
+                #pragma fragment FragBilinear
+            ENDHLSL
+        }
+    }
+
+    Fallback Off
+}

ScriptableRenderPipeline/HDRenderPipeline/HDRP/RenderPipelineResources/Blit.shader.meta

+fileFormatVersion: 2
+guid: 370f7a9cc4e362d488af024d371091e8
+ShaderImporter:
+  externalObjects: {}
+  defaultTextures: []
+  nonModifiableTextures: []
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: