Pixel-Composer/shaders/sh_erode/sh_erode.fsh
2022-11-21 12:38:44 +07:00

49 lines
1.1 KiB
GLSL

//
// Simple passthrough fragment shader
//
varying vec2 v_vTexcoord;
varying vec4 v_vColour;
uniform vec2 dimension;
uniform float size;
uniform int border;
uniform int alpha;
#define TAU 6.28318
float bright(in vec4 col) {
return dot(col.rgb, vec3(0.2126, 0.7152, 0.0722)) * col.a;
}
void main() {
vec2 pixelPosition = v_vTexcoord * dimension;
vec4 point = texture2D( gm_BaseTexture, v_vTexcoord );
vec4 fill = vec4(0.);
if(alpha == 0)
fill.a = 1.;
float tau_div = TAU / 64.;
gl_FragColor = point;
if((alpha == 0 && length(point.rgb) > 0.) || (alpha == 1 && point.a > 0.)) {
for(float i = 1.; i < size; i++) {
for(float j = 0.; j < 64.; j++) {
float ang = j * tau_div;
vec2 pxs = (pixelPosition + vec2( cos(ang) * i, sin(ang) * i)) / dimension;
if(border == 1)
pxs = clamp(pxs, vec2(0.), vec2(1.));
vec4 sam = texture2D( gm_BaseTexture, pxs );
if(pxs.x < 0. || pxs.x > 1. || pxs.y < 0. || pxs.y > 1.) {
gl_FragColor = fill;
break;
}
if((alpha == 0 && length(sam.rgb) == 0.) || (alpha == 1 && sam.a == 0.)) {
gl_FragColor = fill;
break;
}
}
}
}
}