#version 120

uniform sampler2D fbo_texture;
uniform float time;

varying vec2 UV;

float rand(vec2 arg)
{
    return fract(sin(dot(arg, vec2(12.9898, 78.233))) * 43758.5453);
}

void main(void)
{
    vec2 cPos = UV * 2 - 1;
    float cLength = length(cPos);
    vec2 uv = UV + cos(cLength * 100 + time * 10) * 0.0025;
    float argument = atan(time / 20) * sin(time * 10) * 5;
    uv = vec2(cos(argument), sin(argument)) / 50 + uv + (vec2(rand(time * UV), rand(1 + time * UV)) - 0.5) / (10 + 240 * atan(time / 20) * abs(sin(time * 3)));
    float r = abs(rand(vec2(rand(time * UV))) - 0.3);
    gl_FragColor = (r <= 0.0005 ? 1 : 0) + texture2D(fbo_texture, uv);
}