71 lines
1.7 KiB
GLSL
71 lines
1.7 KiB
GLSL
#[compute]
|
|
|
|
#version 450
|
|
|
|
VERSION_DEFINES
|
|
|
|
layout(local_size_x = 8, local_size_y = 8, local_size_z = 1) in;
|
|
|
|
layout(set = 0, binding = 0) uniform sampler2D source_normal;
|
|
layout(r8, set = 1, binding = 0) uniform restrict writeonly image2D dest_roughness;
|
|
|
|
layout(push_constant, binding = 1, std430) uniform Params {
|
|
ivec2 screen_size;
|
|
float curve;
|
|
uint pad;
|
|
}
|
|
params;
|
|
|
|
#define HALF_PI 1.5707963267948966
|
|
|
|
void main() {
|
|
// Pixel being shaded
|
|
ivec2 pos = ivec2(gl_GlobalInvocationID.xy);
|
|
if (any(greaterThan(pos, params.screen_size))) { //too large, do nothing
|
|
return;
|
|
}
|
|
|
|
vec3 normal_accum = vec3(0.0);
|
|
float accum = 0.0;
|
|
for (int i = 0; i <= 1; i++) {
|
|
for (int j = 0; j <= 1; j++) {
|
|
normal_accum += normalize(texelFetch(source_normal, pos + ivec2(i, j), 0).xyz * 2.0 - 1.0);
|
|
accum += 1.0;
|
|
}
|
|
}
|
|
|
|
normal_accum /= accum;
|
|
|
|
float r = length(normal_accum);
|
|
|
|
float limit;
|
|
|
|
if (r < 1.0) {
|
|
float threshold = 0.4;
|
|
|
|
/*
|
|
//Formula from Filament, does not make sense to me.
|
|
|
|
float r2 = r * r;
|
|
float kappa = (3.0f * r - r * r2) / (1.0f - r2);
|
|
float variance = 0.25f / kappa;
|
|
limit = sqrt(min(2.0f * variance, threshold * threshold));
|
|
*/
|
|
/*
|
|
//Formula based on probability distribution graph
|
|
|
|
float width = acos(max(0.0,r)); // convert to angle (width)
|
|
float roughness = pow(width,1.7)*0.854492; //approximate (crappy) formula to convert to roughness
|
|
limit = min(sqrt(roughness), threshold); //convert to perceptual roughness and apply threshold
|
|
*/
|
|
|
|
limit = min(sqrt(pow(acos(max(0.0, r)) / HALF_PI, params.curve)), threshold); //convert to perceptual roughness and apply threshold
|
|
|
|
//limit = 0.5;
|
|
} else {
|
|
limit = 0.0;
|
|
}
|
|
|
|
imageStore(dest_roughness, pos, vec4(limit));
|
|
}
|