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thebookofshaders/09/rays.frag

27 lines
539 B
GLSL

9 years ago
// Author @patriciogv - 2015 - patricio.io
#ifdef GL_ES
precision mediump float;
#endif
const float PI = 3.1415926535897932384626433832795;
uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_time;
float stripes(vec2 st){
return step(.2,abs(sin(st.x*PI)));
}
void main(){
vec2 st = gl_FragCoord.xy/u_resolution.xy;
st.x *= u_resolution.x/u_resolution.y;
vec2 pos = vec2(0.5)-st;
float a = atan(pos.y,pos.x);
float r = length(pos);
vec3 color = vec3(stripes(vec2(a,r)*50.));
gl_FragColor = vec4(color, 1.0);
}