Add sharpening and better AABB history clamp to Screen Space Reflections temporal filter

Source/Engine/Renderer/ScreenSpaceReflectionsPass.cpp

@@ -24,29 +24,23 @@
 
 GPU_CB_STRUCT(Data {
     ShaderGBufferData GBuffer;
-
     float MaxColorMiplevel;
     float TraceSizeMax;
     float MaxTraceSamples;
     float RoughnessFade;
-
     Float2 SSRtexelSize;
     float TemporalTime;
     float BRDFBias;
-
     float WorldAntiSelfOcclusionBias;
     float EdgeFadeFactor;
     float TemporalResponse;
     float TemporalScale;
-
     float RayTraceStep;
     float TemporalEffect;
     float Intensity;
     float FadeOutDistance;
-
     Matrix ViewMatrix;
     Matrix ViewProjectionMatrix;
-
     GlobalSignDistanceFieldPass::ConstantsData GlobalSDF;
     GlobalSurfaceAtlasPass::ConstantsData GlobalSurfaceAtlas;
     });

Source/Shaders/SSR.shader

@@ -5,6 +5,7 @@
 #include "./Flax/ReflectionsCommon.hlsl"
 #include "./Flax/SSR.hlsl"
 #include "./Flax/GBuffer.hlsl"
+#include "./Flax/Temporal.hlsl"
 #include "./Flax/GlobalSignDistanceField.hlsl"
 #include "./Flax/GI/GlobalSurfaceAtlas.hlsl"
 
@@ -15,34 +16,26 @@
 #define SSR_MIX_BLUR 1
 
 META_CB_BEGIN(0, Data)
-
 GBufferData GBuffer;
-
 float MaxColorMiplevel;
 float TraceSizeMax;
 float MaxTraceSamples;
 float RoughnessFade;
-
 float2 SSRtexelSize;
 float TemporalTime;
 float BRDFBias;
-
 float WorldAntiSelfOcclusionBias;
 float EdgeFadeFactor;
 float TemporalResponse;
 float TemporalScale;
-
 float RayTraceStep;
 float TemporalEffect;
 float Intensity;
 float FadeOutDistance;
-
 float4x4 ViewMatrix;
 float4x4 ViewProjectionMatrix;
-
 GlobalSDFData GlobalSDF;
 GlobalSurfaceAtlasData GlobalSurfaceAtlas;
-
 META_CB_END
 
 DECLARE_GBUFFERDATA_ACCESS(GBuffer)
@@ -227,15 +220,11 @@ float4 PS_TemporalPass(Quad_VS2PS input) : SV_Target0
 	// Texture1 - prev frame temporal SSR buffer
 	// Texture2 - motion vectors
 
+	// Sample inputss
 	float2 uv = input.TexCoord;
-
-	// Sample velocity
 	float2 velocity = Texture2.SampleLevel(SamplerLinearClamp, uv, 0).xy;
-
-	// Prepare
 	float2 prevUV = uv - velocity;
 	float4 current = Texture0.SampleLevel(SamplerLinearClamp, uv, 0);
-	float4 previous = Texture1.SampleLevel(SamplerLinearClamp, prevUV, 0);
 	float2 du = float2(SSRtexelSize.x, 0.0);
 	float2 dv = float2(0.0, SSRtexelSize.y);
 
@@ -252,18 +241,23 @@ float4 PS_TemporalPass(Quad_VS2PS input) : SV_Target0
 
 	float4 currentMin = min(currentTopLeft, min(currentTopCenter, min(currentTopRight, min(currentMiddleLeft, min(currentMiddleCenter, min(currentMiddleRight, min(currentBottomLeft, min(currentBottomCenter, currentBottomRight))))))));
 	float4 currentMax = max(currentTopLeft, max(currentTopCenter, max(currentTopRight, max(currentMiddleLeft, max(currentMiddleCenter, max(currentMiddleRight, max(currentBottomLeft, max(currentBottomCenter, currentBottomRight))))))));
+	float4 currentSum = currentTopLeft + currentTopCenter + currentTopRight + currentMiddleLeft + currentMiddleCenter + currentMiddleRight + currentBottomLeft + currentBottomCenter + currentBottomRight;
+	float4 currentAvg = currentSum / 9.0;
 
-	float scale = TemporalScale;
+	// Sample history by clamp it to the nearby colors range to reduce artifacts
+	float lumaOffset = abs(Luminance(currentAvg.rgb) - Luminance(current.rgb));
+	float velocityLength = length(velocity);
+	float aabbMargin = lerp(4.0, 0.25, saturate(velocityLength * 100.0)) * lumaOffset;
+	float4 previous = Texture1.SampleLevel(SamplerLinearClamp, prevUV, 0);
+	previous = ClipToAABB(previous, currentMin - aabbMargin, currentMax + aabbMargin);
+	//previous = clamp(previous, currentMin, currentMax);
 
-	float4 center = (currentMin + currentMax) * 0.5f;
+    // Blend with history sample
-	currentMin = (currentMin - center) * scale + center;
+	float response = TemporalResponse * (1 - velocityLength * 8);
-	currentMax = (currentMax - center) * scale + center;
+	current = lerp(current, previous, saturate(response));
-
-	previous = clamp(previous, currentMin, currentMax);
 	current = clamp(current, 0, HDR_CLAMP_MAX);
 
-	float response = TemporalResponse * (1 - length(velocity) * 8);
+    return current;
-	return lerp(current, previous, saturate(response));
 }
 
 // Pixel Shader for screen space reflections rendering - mix pass

Source/Shaders/TAA.shader

@@ -6,6 +6,7 @@
 #include "./Flax/Common.hlsl"
 #include "./Flax/GBuffer.hlsl"
 #include "./Flax/Noise.hlsl"
+#include "./Flax/Temporal.hlsl"
 
 META_CB_BEGIN(0, Data)
 float2 ScreenSizeInv;
@@ -24,17 +25,6 @@ Texture2D InputHistory : register(t1);
 Texture2D MotionVectors : register(t2);
 Texture2D Depth : register(t3);
 
-// [Pedersen, 2016, "Temporal Reprojection Anti-Aliasing in INSIDE"]
-float4 ClipToAABB(float4 color, float4 minimum, float4 maximum)
-{
-	float4 center = (maximum + minimum) * 0.5;
-	float4 extents = (maximum - minimum) * 0.5;
-	float4 shift = color - center;
-    float4 absUnit = abs(shift / max(extents, 0.0001));
-    float maxUnit = max(max(absUnit.x, absUnit.y), absUnit.z);
-	return maxUnit > 1.0 ? center + (shift / maxUnit) : color;
-}
-
 // Pixel Shader for Temporal Anti-Aliasing
 META_PS(true, FEATURE_LEVEL_ES2)
 float4 PS(Quad_VS2PS input) : SV_Target0
@@ -105,7 +95,6 @@ float4 PS(Quad_VS2PS input) : SV_Target0
 	neighborhoodSharp = float4(1, 0, 0, 1);
 #endif
 	color = lerp(color, neighborhoodSharp, saturate(miss));
-
 	color = clamp(color, 0, HDR_CLAMP_MAX);
 
     // Apply quantization error to reduce yellowish artifacts due to R11G11B10 format

Source/Shaders/Temporal.hlsl

@@ -0,0 +1,19 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#ifndef __TEMPORAL__
+#define __TEMPORAL__
+
+#include "./Flax/Common.hlsl"
+
+// [Pedersen, 2016, "Temporal Reprojection Anti-Aliasing in INSIDE"]
+float4 ClipToAABB(float4 color, float4 minimum, float4 maximum)
+{
+	float4 center = (maximum + minimum) * 0.5;
+	float4 extents = (maximum - minimum) * 0.5;
+	float4 shift = color - center;
+    float4 absUnit = abs(shift / max(extents, 0.0001));
+    float maxUnit = max(max(absUnit.x, absUnit.y), absUnit.z);
+	return maxUnit > 1.0 ? center + (shift / maxUnit) : color;
+}
+
+#endif