// #include //ly.img.cesdk/shader/common/ubq_constants
// #include //ly.img.cesdk/shader/common/ubq_noise
uniform shader image;
uniform float2 imageSize;
uniform float slices;
uniform float offset;
uniform float speedV;
uniform float time;

float steppedVal(float v, float steps) {
  return floor(v * steps) / steps;
}

// returns 0 - 1
float random1d(float n) {
  const float scale = 0.2;
  const float speed = 1.0;  
  return getNoise(float2(n, n), n, scale, speed);
}

// returns 0 - 1
float noise1d(float p) {
  float fl = floor(p);
  float fc = fract(p);
  return mix(random1d(fl), random1d(fl + 1.0), fc);
}

half4 main(float2 coord) {
  float2 uv = coord / imageSize;
  // variable width strips
  float n = noise1d((1 - uv.y) * slices + time * speedV * 3.0);
  float ns = steppedVal(fract(n), slices) + 2.0;

  float nsr = random1d(ns);
  uv.x += nsr * sin(time * TWO_PI + nsr * 20.0) * offset;
  uv *= imageSize;
  return image.eval(uv);
}