#ifdef GL_ES
precision mediump float;
#endif
uniform vec2 resolution;uniform float time;uniform sampler2D backbuffer;
vec2 rand(vec2 p){return fract((pow(p+2.5,p.yx)*tan(time/10.)));}
void main(){vec2 texPos = vec2(gl_FragCoord.xy/resolution) +sin(time)/20.;
vec2 pos = gl_FragCoord.xy/resolution.y;gl_FragColor = vec4(rand(rand(pos)),
tan(rand(pos).y),1)*0.5;gl_FragColor += texture2D(backbuffer, texPos*sin(time)
*1.1)*0.5;}