thebookofshaders/07/circle-making.frag
2015-03-30 07:42:31 -04:00

30 lines
603 B
GLSL

// Author @patriciogv - 2015
// http://patriciogonzalezvivo.com
#ifdef GL_ES
precision mediump float;
#endif
#define PI 3.14159265359
uniform vec2 u_resolution;
uniform float u_time;
void main(){
vec2 st = gl_FragCoord.xy/u_resolution;
float pct = 0.0;
// a. The DISTANCE to the center whick is the
pct = distance(st,vec2(0.5));
// b. The LENGTH to the vector to the center
// vec2 tC = vec2(0.5)-st;
// pct = length(tC);
// c. The SQUARE ROOT of the vector
// pct = sqrt(tC.x*tC.x+tC.y*tC.y);
vec3 color = vec3(pct);
gl_FragColor = vec4( color, 1.0 );
}