color dithering

zenovis/xinxinoptix/PTKernel.cu

@@ -434,10 +434,16 @@ extern "C" __global__ void __raygen__rg()
     params.accum_buffer_S[ image_index ] = make_float3( accum_color_s.x,accum_color_s.y, accum_color_s.z);
     params.accum_buffer_T[ image_index ] = make_float3( accum_color_t.x,accum_color_t.y,accum_color_t.z);
     params.accum_buffer_B[ image_index ] = float_to_half(accum_color_b.x);
-    params.frame_buffer[ image_index ] = make_color ( accum_color );
+
     params.frame_buffer_M[ image_index ] = float3_to_half3(accum_mask);
     params.frame_buffer_P[ image_index ] = float3_to_half3(click_pos);
 
+    auto uv = float2{idx.x+0.5f, idx.y+0.5f};
+    auto dither = InterleavedGradientNoise(uv);
+
+    dither = (dither-0.5f)/255;
+    params.frame_buffer[ image_index ] = make_color( accum_color + dither);
+
     if (params.denoise) {
         params.albedo_buffer[ image_index ] = tmp_albedo;
         params.normal_buffer[ image_index ] = tmp_normal;

zenovis/xinxinoptix/SDK/cuda/random.h

@@ -28,6 +28,9 @@
 
 #pragma once
 
+#include <vector_types.h>
+#include <sutil/vec_math.h>
+
 template<unsigned int N>
 static __host__ __device__ __inline__ unsigned int tea( unsigned int val0, unsigned int val1 )
 {
@@ -150,3 +153,15 @@ float2 sobolRnd2(unsigned int & seed)
 
     //return make_float2(rnd(seed), rnd(seed));
 }
+
+__forceinline__ __device__ float fractf(float x)
+{
+	return x - floorf(x);
+}
+
+/* Gradient noise from Jorge Jimenez's presentation: */
+/* http://www.iryoku.com/next-generation-post-processing-in-call-of-duty-advanced-warfare */
+__forceinline__ __device__ float InterleavedGradientNoise(float2 uv)
+{
+	return fractf(52.9829189 * fractf(dot(uv, float2{0.06711056, 0.00583715})));
+}