texture

sample.frag

#ifdef GL_ES
precision mediump float;
#endif

uniform float u_time;
uniform vec2 u_resolution;

uniform sampler2D u_tex0;

const mat2 m=mat2(.80,.60,-.60,.80);

float hash(float n)
{
    return fract(sin(n)*43758.5453);
}

float noise(in vec2 x)
{
    vec2 p=floor(x);
    vec2 f=fract(x);
    f=f*f*(3.-2.*f);
    float n=p.x+p.y*57.;
    return mix(mix(hash(n+0.),hash(n+1.),f.x),
    mix(hash(n+57.),hash(n+58.),f.x),f.y);
}

float fbm(vec2 p){
    float f=0.;
    f+=.5*noise(p);p*=m*2.02;
    f+=.25*noise(p);p*=m*2.03;
    f+=.125*noise(p);p*=m*2.01;
    f+=.0625*noise(p);p*=m*2.04;
    f/=.9375;
    return f;
}

float N21(vec2 p){
    p=fract(p*vec2(233.34,851.73));
    p+=dot(p,p+23.45);
    return fract(p.x*p.y);
}

vec2 N22(vec2 p){
    float n=N21(p);
    return vec2(n,N21(p+n));
}

vec2 GetPos(vec2 id,vec2 offset){
    vec2 n=N22(id+offset)*u_time;    
    return offset+sin(n)*.1;
}

void main(){
    vec2 uv=gl_FragCoord.xy/u_resolution.xy;
    vec3 col=vec3(0.);
    
    vec2 p = GetPos(uv, vec2(.45));
    uv = uv * vec2(cos(p.x - p.y), sin(p.x - p.y + u_time));
    gl_FragColor = texture2D(u_tex0, uv);
}