// TVStatic — generated from https://github.com/gl-transitions/gl-transitions/blob/master/transitions/TVStatic.glsl
// Author: Brandon Anzaldi
// License: MIT
// Description: Cuts to full-screen TV static, then to the incoming image

uniform shader _from;
uniform shader _to;
uniform float2 _resolution;
uniform float progress;
uniform float ratio;

vec4 getFromColor(vec2 uv) { return vec4(unpremul(_from.eval(vec2(uv.x, 1.0 - uv.y) * _resolution))); }
vec4 getToColor(vec2 uv) { return vec4(unpremul(_to.eval(vec2(uv.x, 1.0 - uv.y) * _resolution))); }

uniform float offset; 

highp float noise(vec2 co)
{
    highp float a = 12.9898;
    highp float b = 78.233;
    highp float c = 43758.5453;
    highp float dt= dot(co.xy * progress, vec2(a, b));
    highp float sn= mod(dt,3.14);
    return fract(sin(sn) * c);
}

vec4 transition(vec2 p) {
  if (progress < offset) {
    return getFromColor(p);
  } else if (progress > (1.0 - offset)) {
    return getToColor(p);
  } else {
    return vec4(vec3(noise(p)), 1.0);
  }
}

half4 main(float2 _coord) {
  vec2 _uv = _coord / _resolution;
  vec4 _c = clamp(transition(vec2(_uv.x, 1.0 - _uv.y)), 0.0, 1.0);
  return half4(_c.rgb * _c.a, _c.a);
}