// Found this on GLSL sandbox. I really liked it, changed a few things and made it tileable.
// :)
// by David Hoskins.
// Original water turbulence effect by joltz0r


#define TAU 6.28318530718
#define MAX_ITER 5
void mainImage(out vec4 fragColor,in vec2 fragCoord){
double time=iTime*.5+23.0;
vec2 uv=fragCoord.xy/iResolution.xy;
vec2 p=mod(uv*TAU,TAU)-250.0;
vec2 i=vec2(p);
float c=1.0;
float inten=.005;
for(int n=0;n<MAX_ITER;n++){
float t=time*(1.0-(3.5/float(n+1)));
i=p+vec2(cos(t-i.x)+sin(t+i.y),sin(t-i.y)+cos(t+i.x));
c+=1.0/length(vec2(p.x/(sin(i.x+t)/inten),p.y/(cos(i.y+t)/inten)));
}
c/=float(MAX_ITER);
c=1.17-pow(c,1.4);
vec3 colour=vec3(pow(abs(c),8.0));
colour=clamp(colour+vec3(0.0,0.35,0.5),0.0,1.0);
fragColor=vec4(colour,1.0);
}