thebookofshaders/15/texture-kaleidoscope.frag

44 lines
931 B
GLSL
Raw Normal View History

2015-05-05 14:19:16 +00:00
// Author @patriciogv - 2015
// http://patriciogonzalezvivo.com
2015-05-04 15:05:46 +00:00
#ifdef GL_ES
precision mediump float;
#endif
#define PI 3.14159265359
#define TWO_PI 6.28318530718
uniform sampler2D u_tex0;
uniform vec2 u_tex0Resolution;
uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_time;
// Based on Asalga shader
// https://www.shadertoy.com/view/4ss3WX
void main () {
vec2 st = gl_FragCoord.xy/u_resolution.xy;
float time = u_time*0.1;
// move to the center
st = st - 0.5;
// cartesian to polar coordinates
float r = length(st);
float a = atan(st.y, st.x);
// Repeat side acoriding to angle
float sides = 10.;
float ma = mod(a, TWO_PI/sides);
ma = abs(ma - PI/sides);
// polar to cartesian coordinates
st = r * vec2(cos(ma), sin(ma));
st = fract(st+time);
vec4 color = vec4(st.x,st.y,0.0,1.0);
color = texture2D(u_tex0,st);
gl_FragColor = color;
}