47_fillCircle.frag

#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;

    pct = step(0.5, distance(st,vec2(0.5))*2.0);

    vec3 color = 1.0 - vec3(pct);

  gl_FragColor = vec4( color, 1.0 );
}