float r(vec2 n)
{
    return fract(cos(dot(n,vec2(70.26,200.12)))*900.63);
}
float noise(vec2 n)
{
    vec2 fn = floor(n);
    vec2 sn = smoothstep(vec2(0),vec2(1),fract(n));
    
    float h1 = mix(r(fn),r(fn+vec2(1,0)),sn.x);
    float h2 = mix(r(fn+vec2(0,1)),r(fn+vec2(1)),sn.x);
    return mix(h1,h2,sn.y);
}
float value(vec2 n)
{
    float total;
    total = noise(n/32.)*0.5454+noise(n/16.)*0.1+noise(n/8.)*0.1
            +noise(n/4.)*0.05+noise(n/2.)*0.8763+noise(n)*0.0333;
 	return total;
}
void main() {
	gl_FragColor = vec4(vec3(value(u_time*16.+gl_FragCoord.xy/4.)),3.0);
}
     
//created by firstuser at shadergrounds.com