glsl fiddling

glslang

// From iq's latest live coding video, "a simple eye ball"

#ifdef GL_ES
precision highp float;
#endif

uniform vec2 resolution;
uniform vec2 mouse;
uniform float time;

const mediump mat4 rgbToYuv = mat4( 0.257,  0.439,  -0.148, 0.06, 
                                    0.504, -0.368,  -0.291, 0.5,
                                    0.098, -0.071,   0.439, 0.5, 
                                     0.0,     0.0,     0.0, 1.0);

const mediump mat4 yuvToRgb = mat4( 1.164,  1.164,  1.164,  -0.07884, 
                                    2.018, -0.391,    0.0,  1.153216,
                                      0.0, -0.813,  1.596,  0.53866, 
                                      0.0,    0.0,    0.0,  1.0);



void main(void)
{
	vec2 O = -1.0 + 2.0 * (mouse.xy);
    vec2 q = gl_FragCoord.xy / resolution.xy;
    vec2 p = -1.0 + 2.0 * q;
    p.x *= resolution.x/resolution.y;
	
    float th = atan(p.y, p.x - O.x);
    float r = sqrt(dot(p - O,p));
    float rr = sqrt(dot(p - O,p - O));
    float rays = 12.0;
    float waves = rays / 4.0 + tan(cos(time));
    float PI = 3.14159265; float PI_2 = PI / 2.0;
    vec4 col = vec4(abs(th/PI_2 + PI*(sin(time))) - 0.5, 0.5 ,1.0 - sqrt((sin(r*r  + rr*rr))),0);
    gl_FragColor = col * yuvToRgb;
}