Fixed TAA not using Gather correctly in DX11 & PSSL compatible platforms

Author: Chman

PostProcessing/Resources/Shaders/TAA.cginc

@@ -10,8 +10,6 @@
 // -----------------------------------------------------------------------------
 // Solver
 
-#define TAA_USE_GATHER4_FOR_DEPTH_SAMPLE (SHADER_TARGET >= 41)
-
 #define TAA_USE_STABLE_BUT_GHOSTY_VARIANT 0
 
 #if !defined(TAA_DILATE_MOTION_VECTOR_SAMPLE)
@@ -39,13 +37,7 @@ struct OutputSolver
 sampler2D _HistoryTex;
 
 sampler2D _CameraMotionVectorsTexture;
-
-#if TAA_USE_GATHER4_FOR_DEPTH_SAMPLE
-Texture2D _CameraDepthTexture;
-SamplerState sampler_CameraDepthTexture;
-#else
 sampler2D _CameraDepthTexture;
-#endif
 
 float4 _HistoryTex_TexelSize;
 float4 _CameraDepthTexture_TexelSize;
@@ -74,20 +66,14 @@ VaryingsSolver VertSolver(AttributesDefault input)
 float2 GetClosestFragment(float2 uv)
 {
     const float2 k = _CameraDepthTexture_TexelSize.xy;
-
-#if TAA_USE_GATHER4_FOR_DEPTH_SAMPLE
-    const float4 neighborhood = _CameraDepthTexture.Gather(sampler_CameraDepthTexture, uv, int2(1, 1));
-    float3 result = float3(0.0, 0.0, _CameraDepthTexture.Sample(sampler_CameraDepthTexture, uv).r);
-#else
     const float4 neighborhood = float4(
         SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, uv - k),
         SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, uv + float2(k.x, -k.y)),
         SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, uv + float2(-k.x, k.y)),
         SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, uv + k)
         );
-    float3 result = float3(0.0, 0.0, SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, uv));
-#endif
 
+    float3 result = float3(0.0, 0.0, SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, uv));
     result = lerp(result, float3(-1.0, -1.0, neighborhood.x), step(neighborhood.x, result.z));
     result = lerp(result, float3( 1.0, -1.0, neighborhood.y), step(neighborhood.y, result.z));
     result = lerp(result, float3(-1.0,  1.0, neighborhood.z), step(neighborhood.z, result.z));