Pixel-Composer/shaders/sh_rsh_rotate/sh_rsh_rotate.fsh
2023-07-17 19:58:33 +02:00

35 lines
748 B
GLSL

//
// Simple passthrough fragment shader
//
varying vec2 v_vTexcoord;
varying vec4 v_vColour;
uniform vec2 dimension;
#define PI 3.14159265359
vec4 sample( vec2 pos ) {
if(pos.x < 0. || pos.y < 0.) return vec4(0.);
if(pos.x > 1. || pos.y > 1.) return vec4(0.);
return texture2D( gm_BaseTexture, pos );
}
void main() {
vec2 tx = 1. / dimension;
//vec4 a = sample( v_vTexcoord );
//gl_FragColor = a;
//if(a.a == 1.) return;
float dist = length(v_vTexcoord - vec2(0.5, 0.5)) * 3.;
float cir = PI * dist * dimension.x;
for( float i = 0.; i < cir; i++ ) {
float angle = 2. * PI * i / cir;
vec4 b = sample( vec2(0.5, 0.5) + vec2(cos(angle), sin(angle)) * dist * 0.5 );
if(b.a == 1.) {
gl_FragColor = b;
return;
}
}
}