TAA: removed unneeded FEATURE_FLAG_REVERSED_DEPTH flag (#228)

Author: TheMostDiligent

PostProcess/TemporalAntiAliasing/interface/TemporalAntiAliasing.hpp

@@ -55,17 +55,14 @@ class TemporalAntiAliasing
     {
         FEATURE_FLAG_NONE = 0u,
 
-        // Indicates that the application uses a reversed depth buffer.
-        FEATURE_FLAG_REVERSED_DEPTH = 1u << 0u,
-
         // Use Gaussian weighting in the variance clipping step.
-        FEATURE_FLAG_GAUSSIAN_WEIGHTING = 1u << 1u,
+        FEATURE_FLAG_GAUSSIAN_WEIGHTING = 1u << 0u,
 
         // Use Catmull-Rom filter to sample the history buffer.
-        FEATURE_FLAG_BICUBIC_FILTER = 1u << 2u,
+        FEATURE_FLAG_BICUBIC_FILTER = 1u << 1u,
 
         // Use YCoCg color space for color clipping.
-        FEATURE_FLAG_YCOCG_COLOR_SPACE = 1u << 3u
+        FEATURE_FLAG_YCOCG_COLOR_SPACE = 1u << 2u
     };
 
     struct RenderAttributes

PostProcess/TemporalAntiAliasing/src/TemporalAntiAliasing.cpp

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2024 Diligent Graphics LLC
+ *  Copyright 2024-2025 Diligent Graphics LLC
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -234,7 +234,6 @@ void TemporalAntiAliasing::PrepareShadersAndPSO(const RenderAttributes& RenderAt
 
         ShaderMacroHelper Macros;
         Macros.Add("TAA_OPTION_GAUSSIAN_WEIGHTING", (FeatureFlags & FEATURE_FLAG_GAUSSIAN_WEIGHTING) != 0);
-        Macros.Add("TAA_OPTION_INVERTED_DEPTH", (FeatureFlags & FEATURE_FLAG_REVERSED_DEPTH) != 0);
         Macros.Add("TAA_OPTION_BICUBIC_FILTER", (FeatureFlags & FEATURE_FLAG_BICUBIC_FILTER) != 0);
         Macros.Add("TAA_OPTION_YCOCG_COLOR_SPACE", (FeatureFlags & FEATURE_FLAG_YCOCG_COLOR_SPACE) != 0);
 

Shaders/PostProcess/TemporalAntiAliasing/private/TAA_ComputeTemporalAccumulation.fx

@@ -3,14 +3,7 @@
 #include "PostFX_Common.fxh"
 #include "TemporalAntiAliasingStructures.fxh"
 
-#define FLT_EPS   5.960464478e-8
-#define FLT_MAX   3.402823466e+38
-
-#if TAA_OPTION_INVERTED_DEPTH
-    #define DepthFarPlane 0.0
-#else
-    #define DepthFarPlane 1.0
-#endif // TAA_OPTION_INVERTED_DEPTH
+#define FLT_EPS 5.960464478e-8
 
 cbuffer cbCameraAttribs
 {
@@ -119,9 +112,11 @@ float3 ClipToAABB(float3 ColorPrev, float3 ColorCurr, float3 AABBCentre, float3
 
 float ComputeDepthDisocclusionWeight(float CurrDepth, float PrevDepth)
 {
-    float LinearDepthCurr = DepthToCameraZ(CurrDepth, g_PrevCamera.mProj);
-    float LinearDepthPrev = DepthToCameraZ(PrevDepth, g_PrevCamera.mProj);
-    return exp(-abs(LinearDepthPrev - LinearDepthCurr) / LinearDepthCurr);
+    float LinearDepthCurr  = abs(DepthToCameraZ(CurrDepth, g_PrevCamera.mProj));
+    float LinearDepthPrev  = abs(DepthToCameraZ(PrevDepth, g_PrevCamera.mProj));
+    float MaxLinearDepth   = max(LinearDepthCurr, LinearDepthPrev);
+    float LinearDepthDelta = abs(LinearDepthCurr - LinearDepthPrev);
+    return exp(-LinearDepthDelta / max(MaxLinearDepth, 1e-6));
 }
 
 float ComputeDepthDisocclusion(float2 Position, float2 PrevPosition)