thebookofshaders/07/circle-making.frag
2017-08-23 11:34:44 +02:00

33 lines
707 B
GLSL

// Author @patriciogv - 2015
// http://patriciogonzalezvivo.com
#ifdef GL_ES
precision mediump float;
#endif
uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_time;
void main(){
vec2 st = gl_FragCoord.xy/u_resolution;
float pct = 0.0;
// a. The DISTANCE from the pixel to the center
pct = distance(st,vec2(0.5));
// b. The LENGTH of the vector
// from the pixel to the center
// vec2 toCenter = vec2(0.5)-st;
// pct = length(toCenter);
// c. The SQUARE ROOT of the vector
// from the pixel to the center
// vec2 tC = vec2(0.5)-st;
// pct = sqrt(tC.x*tC.x+tC.y*tC.y);
vec3 color = vec3(pct);
gl_FragColor = vec4( color, 1.0 );
}