Pixel-Composer/shaders/sh_kuwahara/sh_kuwahara.fsh
2024-02-09 20:43:03 +07:00

109 lines
No EOL
2.6 KiB
GLSL

/*
Generalized Kuwahara filter, based on work of Acerola
Basically Acerola code rewritten to Shadertoy
- https://www.youtube.com/watch?v=LDhN-JK3U9g
- https://github.com/GarrettGunnell/Post-Processing/tree/main/Assets/Kuwahara%20Filter
*/
varying vec2 v_vTexcoord;
varying vec4 v_vColour;
#define PI 3.14159265358979323846;
#define MAX_RAD 64
const float q = 18.;
uniform vec2 dimension;
uniform int radius;
void main () {
vec2 tx = 1. / dimension;
float zeta = 2. / float(radius);
float zeroCross = 2.;
float sinZeroCross = sin(zeroCross);
float eta = 0.;
vec4 m[8];
vec3 s[8];
for (int k = 0; k < 8; ++k) {
m[k] = vec4(0.);
s[k] = vec3(0.);
}
for (int y = -MAX_RAD; y <= MAX_RAD; y++)
for (int x = -MAX_RAD; x <= MAX_RAD; x++) {
if(y < -radius) continue;
if(x < -radius) continue;
if(x > radius) continue;
if(y > radius) break;
vec2 v = vec2(x, y) / float(radius);
vec3 c = texture2D( gm_BaseTexture, v_vTexcoord + vec2(x, y) * tx).xyz;
c = clamp(c, 0., 1.);
float sum = 0.;
float w[8];
float z, vxx, vyy;
/* Calculate Polynomial Weights */
vxx = zeta - eta * v.x * v.x;
vyy = zeta - eta * v.y * v.y;
z = max(0., v.y + vxx);
w[0] = z * z;
sum += w[0];
z = max(0., -v.x + vyy);
w[2] = z * z;
sum += w[2];
z = max(0., -v.y + vxx);
w[4] = z * z;
sum += w[4];
z = max(0., v.x + vyy);
w[6] = z * z;
sum += w[6];
v = sqrt(2.0) / 2.0 * vec2(v.x - v.y, v.x + v.y);
vxx = zeta - eta * v.x * v.x;
vyy = zeta - eta * v.y * v.y;
z = max(0., v.y + vxx);
w[1] = z * z;
sum += w[1];
z = max(0., -v.x + vyy);
w[3] = z * z;
sum += w[3];
z = max(0., -v.y + vxx);
w[5] = z * z;
sum += w[5];
z = max(0., v.x + vyy);
w[7] = z * z;
sum += w[7];
float g = exp(-3.125 * dot(v, v)) / (sum + 0.0001);
for (int k = 0; k < 8; k++) {
float wk = w[k] * g;
m[k] += vec4(c * wk, wk);
s[k] += c * c * wk;
}
}
vec4 ou = vec4(0.);
for (int k = 0; k < 8; k++) {
m[k].rgb /= m[k].w;
s[k] = abs(s[k] / m[k].w - m[k].rgb * m[k].rgb);
float sigma2 = s[k].r + s[k].g + s[k].b;
float w = 1.0 / (1.0 + pow(1000.0 * sigma2, 0.5 * q));
ou += vec4(m[k].rgb * w, w);
}
gl_FragColor = clamp((ou / ou.w), 0.0, 1.0);
}