Pixel-Composer/shaders/sh_pb_hash/sh_pb_hash.fsh
2023-07-23 20:21:35 +02:00

70 lines
1.5 KiB
GLSL

//
// Simple passthrough fragment shader
//
varying vec2 v_vTexcoord;
varying vec4 v_vColour;
uniform vec2 dimension;
uniform vec4 color;
uniform float hash;
uniform int invert;
uniform float dissolve;
uniform vec2 dissolveSca;
uniform int dissolveItr;
///////////////////// PERLIN START /////////////////////
float random (in vec2 st) { return fract(sin(dot(st.xy, vec2(12.9898, 78.233))) * 43758.5453123); }
float noise (in vec2 st) {
vec2 i = floor(st);
vec2 f = fract(st);
// Four corners in 2D of a tile
float a = random(i);
float b = random(i + vec2(1.0, 0.0));
float c = random(i + vec2(0.0, 1.0));
float d = random(i + vec2(1.0, 1.0));
// Cubic Hermine Curve. Same as SmoothStep()
vec2 u = f * f * (3.0 - 2.0 * f);
// Mix 4 coorners percentages
return mix(mix(a, b, u.x), mix(c, d, u.x), u.y);
}
float perlin ( vec2 pos, int iteration ) {
float amp = pow(2., float(iteration) - 1.) / (pow(2., float(iteration)) - 1.);
float n = 0.;
for(int i = 0; i < iteration; i++) {
n += noise(pos) * amp;
amp *= .5;
pos *= 2.;
}
return n;
}
///////////////////// PERLIN END /////////////////////
void main() {
gl_FragColor = texture2D( gm_BaseTexture, v_vTexcoord );
if(gl_FragColor.a == 0.) return;
vec2 px = v_vTexcoord * dimension;
float index;
if(invert == 1) index = px.x - px.y;
else index = px.x + px.y;
if(dissolve > 0. && perlin( v_vTexcoord * dimension / dissolveSca, dissolveItr ) <= dissolve)
return;
if(mod(index, hash) >= hash / 2.)
gl_FragColor = color;
}