#ifdef GL_ES precision mediump float; #endif #define TAU 6.28318530718 uniform vec2 u_resolution; uniform float u_time; vec3 hsb2rgb( in vec3 c ){ vec3 rgb = clamp(abs(mod(c.x*6.0+vec3(0.0,4.0,2.0), 6.0)-3.0)-1.0, 0.0, 1.0 ); rgb = rgb*rgb*(3.0-2.0*rgb); return c.z * mix( vec3(1.0), rgb, c.y); } void main(){ vec2 st = gl_FragCoord.xy/u_resolution; vec3 color = vec3(0.0); vec2 toCenter = (vec2(sin(u_time*0.5), cos(u_time*0.5))-st); float angle = atan(toCenter.y,toCenter.x)*u_time*3.0; float radius = length(toCenter)*2.0; color = hsb2rgb(vec3((angle/TAU)+0.5,radius,1.0)); gl_FragColor = vec4(color,1.0); }