From 7aded7d53366442941272da756b64b9d52a29a2b Mon Sep 17 00:00:00 2001
From: Alexander Gauggel <agauggel@uni-koblenz.de>
Date: Tue, 17 Aug 2021 15:49:04 +0200
Subject: [PATCH] [#106] Correct handling of motion blur motion vectors
according to paper
---
.../resources/shaders/motionBlur.comp | 26 +++++++++++++------
.../resources/shaders/motionBlurConfig.inc | 1 +
.../resources/shaders/motionVectorMax.comp | 3 +--
projects/indirect_dispatch/src/App.cpp | 2 +-
4 files changed, 21 insertions(+), 11 deletions(-)
create mode 100644 projects/indirect_dispatch/resources/shaders/motionBlurConfig.inc
diff --git a/projects/indirect_dispatch/resources/shaders/motionBlur.comp b/projects/indirect_dispatch/resources/shaders/motionBlur.comp
index 62bae130..5c196016 100644
--- a/projects/indirect_dispatch/resources/shaders/motionBlur.comp
+++ b/projects/indirect_dispatch/resources/shaders/motionBlur.comp
@@ -1,5 +1,6 @@
#version 440
#extension GL_GOOGLE_include_directive : enable
+#include "motionBlurConfig.inc"
layout(set=0, binding=0) uniform texture2D inColor;
layout(set=0, binding=1) uniform texture2D inDepth;
@@ -10,7 +11,7 @@ layout(set=0, binding=4, r11f_g11f_b10f) uniform image2D outImage;
layout(local_size_x = 8, local_size_y = 8, local_size_z = 1) in;
layout( push_constant ) uniform constants{
- float motionFactor; // computed from delta time and shutter speed
+ float motionScaleFactor; // computed from delta time and shutter speed
float minVelocity;
// camera planes are needed to linearize depth
float cameraNearPlane;
@@ -64,11 +65,26 @@ float computeSampleWeigth(SampleData mainPixel, SampleData samplePixel){
return weight;
}
+// see "A Reconstruction Filter for Plausible Motion Blur", section 2.2
+vec2 rescaleMotion(vec2 motion){
+ // every frame a pixel should blur over the distance it moves
+ // as we blur in two directions (where it was and where it will be) we must half the motion
+ vec2 motionHalf = motion * 0.5;
+ vec2 motionScaled = motionHalf * motionScaleFactor; // scale factor contains shutter speed and delta time
+
+ // pixels are anisotropic so the smaller dimension is used, so the clamping is conservative
+ float pixelSize = 1.f / max(imageSize(outImage).x, imageSize(outImage).y);
+ float velocity = length(motionScaled);
+ float epsilon = 0.0001;
+ // this clamps the motion to not exceed the radius given by the motion tile size
+ return motionScaled * max(0.5 * pixelSize, min(velocity, motionTileSize * pixelSize)) / (velocity + epsilon);
+}
+
SampleData loadSampleData(vec2 uv){
SampleData data;
data.uv = uv;
- data.motion = texture(sampler2D(inMotion, nearestSampler), uv).rg * motionFactor;
+ data.motion = rescaleMotion(texture(sampler2D(inMotion, nearestSampler), uv).rg);
data.velocity = length(data.motion);
data.depthLinear = texture(sampler2D(inDepth, nearestSampler), uv).r;
data.depthLinear = linearizeDepth(data.depthLinear, cameraNearPlane, cameraFarPlane);
@@ -105,12 +121,6 @@ void main(){
imageStore(outImage, coord, vec4(color, 0.f));
return;
}
-
- // TODO: check if a max velocity is necessary
- // // TODO: should be configurable by user or computed by velocity tile sizes
- // const float maxBlurDistance = 0.075;
- // if(mainPixel.velocity > maxBlurDistance)
- // motion *= maxBlurDistance / velocity;
vec3 color = vec3(0);
float weightSum = 0;
diff --git a/projects/indirect_dispatch/resources/shaders/motionBlurConfig.inc b/projects/indirect_dispatch/resources/shaders/motionBlurConfig.inc
new file mode 100644
index 00000000..fdd915c8
--- /dev/null
+++ b/projects/indirect_dispatch/resources/shaders/motionBlurConfig.inc
@@ -0,0 +1 @@
+const int motionTileSize = 20;
\ No newline at end of file
diff --git a/projects/indirect_dispatch/resources/shaders/motionVectorMax.comp b/projects/indirect_dispatch/resources/shaders/motionVectorMax.comp
index 725fc3f4..65a6186c 100644
--- a/projects/indirect_dispatch/resources/shaders/motionVectorMax.comp
+++ b/projects/indirect_dispatch/resources/shaders/motionVectorMax.comp
@@ -1,5 +1,6 @@
#version 440
#extension GL_GOOGLE_include_directive : enable
+#include "motionBlurConfig.inc"
layout(set=0, binding=0) uniform texture2D inMotion;
layout(set=0, binding=1) uniform sampler textureSampler;
@@ -7,8 +8,6 @@ layout(set=0, binding=2, rgba8) uniform image2D outMotionMax;
layout(local_size_x = 8, local_size_y = 8, local_size_z = 1) in;
-const int motionTileSize = 20;
-
void main(){
ivec2 outImageRes = imageSize(outMotionMax);
diff --git a/projects/indirect_dispatch/src/App.cpp b/projects/indirect_dispatch/src/App.cpp
index 88fdca59..3b9992ed 100644
--- a/projects/indirect_dispatch/src/App.cpp
+++ b/projects/indirect_dispatch/src/App.cpp
@@ -89,7 +89,7 @@ void App::run() {
float objectVerticalSpeed = 5;
float motionBlurMinVelocity = 0.001;
- int cameraShutterSpeedInverse = 30;
+ int cameraShutterSpeedInverse = 24;
float motionVectorVisualisationRange = 0.008;
glm::mat4 mvpPrevious = glm::mat4(1.f);
--
GitLab