From b5f2879871b32cc098fa0dfa9794d82afe74506a Mon Sep 17 00:00:00 2001
From: Alexander Gauggel <agauggel@uni-koblenz.de>
Date: Mon, 16 Aug 2021 23:14:16 +0200
Subject: [PATCH] [#106] Replaced motion blur noise with dither to reduce
visible noise
---
.../resources/shaders/motionBlur.comp | 28 +++++++++----------
.../shaders/motionVectorMaxNeighbourhood.comp | 2 --
projects/indirect_dispatch/src/App.cpp | 2 --
3 files changed, 13 insertions(+), 19 deletions(-)
diff --git a/projects/indirect_dispatch/resources/shaders/motionBlur.comp b/projects/indirect_dispatch/resources/shaders/motionBlur.comp
index 233947d1..62bae130 100644
--- a/projects/indirect_dispatch/resources/shaders/motionBlur.comp
+++ b/projects/indirect_dispatch/resources/shaders/motionBlur.comp
@@ -15,7 +15,6 @@ layout( push_constant ) uniform constants{
// camera planes are needed to linearize depth
float cameraNearPlane;
float cameraFarPlane;
- float time;
};
float linearizeDepth(float depth, float near, float far){
@@ -77,19 +76,16 @@ SampleData loadSampleData(vec2 uv){
return data;
}
-// simple hash/noise function from: https://www.shadertoy.com/view/ttc3zr
-uint murmurHash12(uvec2 src) {
- const uint M = 0x5bd1e995u;
- uint h = 1190494759u;
- src *= M; src ^= src>>24u; src *= M;
- h *= M; h ^= src.x; h *= M; h ^= src.y;
- h ^= h>>13u; h *= M; h ^= h>>15u;
- return h;
-}
-
-float hash12(vec2 src) {
- uint h = murmurHash12(floatBitsToUint(src));
- return uintBitsToFloat(h & 0x007fffffu | 0x3f800000u) - 1.0;
+// simple binary dither pattern
+// could be optimized to avoid modulo and branch
+float dither(ivec2 coord){
+
+ int ditherSize = 4;
+
+ bool x = coord.x % ditherSize < (ditherSize / 2);
+ bool y = coord.y % ditherSize < (ditherSize / 2);
+
+ return x ^^ y ? 1 : 0;
}
void main(){
@@ -126,7 +122,9 @@ void main(){
vec2 uvEnd = clamp(uv + mainPixel.motion, 0, 1);
// samples are placed evenly, but the entire filter is jittered
- float random = hash12(uv + time) - 0.5; // in range [-0.5, 0.5]
+ // dither returns either 0 or 1
+ // the sampleUV code expects an offset in range [-0.5, 0.5], so the dither is rescaled to a binary -0.25/0.25
+ float random = dither(coord) * 0.5 - 0.25;
for(int i = 0; i < sampleCount; i++){
vec2 sampleUV = mix(uvStart, uvEnd, (i + random + 1) / float(sampleCount + 1));
diff --git a/projects/indirect_dispatch/resources/shaders/motionVectorMaxNeighbourhood.comp b/projects/indirect_dispatch/resources/shaders/motionVectorMaxNeighbourhood.comp
index 85d45235..90f9acce 100644
--- a/projects/indirect_dispatch/resources/shaders/motionVectorMaxNeighbourhood.comp
+++ b/projects/indirect_dispatch/resources/shaders/motionVectorMaxNeighbourhood.comp
@@ -7,8 +7,6 @@ layout(set=0, binding=2, rgba8) uniform image2D outMotionMaxNeighbourhood;
layout(local_size_x = 8, local_size_y = 8, local_size_z = 1) in;
-const int motionTileSize = 8;
-
void main(){
ivec2 outImageRes = imageSize(outMotionMaxNeighbourhood);
diff --git a/projects/indirect_dispatch/src/App.cpp b/projects/indirect_dispatch/src/App.cpp
index 0856173a..02442423 100644
--- a/projects/indirect_dispatch/src/App.cpp
+++ b/projects/indirect_dispatch/src/App.cpp
@@ -305,7 +305,6 @@ void App::run() {
float minVelocity;
float cameraNearPlane;
float cameraFarPlane;
- float time;
};
MotionBlurConstantData motionBlurConstantData;
@@ -323,7 +322,6 @@ void App::run() {
m_cameraManager.getActiveCamera().getNearFar(cameraNear, cameraFar);
motionBlurConstantData.cameraNearPlane = cameraNear;
motionBlurConstantData.cameraFarPlane = cameraFar;
- motionBlurConstantData.time = fCurrentTime;
vkcv::PushConstants motionBlurPushConstants(sizeof(motionBlurConstantData));
motionBlurPushConstants.appendDrawcall(motionBlurConstantData);
--
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