Kelsidavis-WoWee/assets/shaders/fsr2_motion.comp.glsl
Kelsi c3047c33ba FSR2: fix motion vector jitter, add bicubic anti-ringing, depth-dilated MVs
- Motion shader: unjitter NDC before reprojection (ndc+jitter, not ndc-jitter),
  compute motion against unjittered UV so static scenes produce zero motion
- Pass jitter offset to motion shader (push constant 80→96 bytes)
- Accumulate shader: restore Catmull-Rom bicubic with anti-ringing clamp to
  prevent negative-lobe halos at edges while maintaining sharpness
- Add depth-dilated motion vectors (3x3 nearest-to-camera) to prevent
  background MVs bleeding over foreground edges
- Widen neighborhood clamp gamma to 3.0, uniform 5% blend with
  disocclusion/velocity reactive boosting
2026-03-08 14:18:00 -07:00

45 lines
1.7 KiB
GLSL

#version 450
layout(local_size_x = 8, local_size_y = 8) in;
layout(set = 0, binding = 0) uniform sampler2D depthBuffer;
layout(set = 0, binding = 1, rg16f) uniform writeonly image2D motionVectors;
layout(push_constant) uniform PushConstants {
mat4 reprojMatrix; // prevUnjitteredVP * inverse(currentUnjitteredVP)
vec4 resolution; // xy = internal size, zw = 1/internal size
vec4 jitterOffset; // xy = current jitter (NDC), zw = unused
} pc;
void main() {
ivec2 pixelCoord = ivec2(gl_GlobalInvocationID.xy);
ivec2 imgSize = ivec2(pc.resolution.xy);
if (pixelCoord.x >= imgSize.x || pixelCoord.y >= imgSize.y) return;
float depth = texelFetch(depthBuffer, pixelCoord, 0).r;
// Pixel center UV and NDC
vec2 uv = (vec2(pixelCoord) + 0.5) * pc.resolution.zw;
vec2 ndc = uv * 2.0 - 1.0;
// Unjitter the NDC: the scene was rendered with jitter applied to
// projection[2][0/1]. For RH perspective (P[2][3]=-1, clip.w=-vz):
// jittered_ndc = unjittered_ndc - jitter
// unjittered_ndc = ndc + jitter
vec2 unjitteredNDC = ndc + pc.jitterOffset.xy;
// Reproject to previous frame via unjittered VP matrices
vec4 clipPos = vec4(unjitteredNDC, depth, 1.0);
vec4 prevClip = pc.reprojMatrix * clipPos;
vec2 prevNdc = prevClip.xy / prevClip.w;
vec2 prevUV = prevNdc * 0.5 + 0.5;
// Current unjittered UV for this pixel's world content
vec2 currentUnjitteredUV = unjitteredNDC * 0.5 + 0.5;
// Motion between unjittered positions — jitter-free.
// For a static scene (identity reprojMatrix), this is exactly zero.
vec2 motion = prevUV - currentUnjitteredUV;
imageStore(motionVectors, pixelCoord, vec4(motion, 0.0, 0.0));
}