// burn — generated from https://github.com/gl-transitions/gl-transitions/blob/master/transitions/burn.glsl
// Author: gre
// License: MIT
// Description: A crossfade that brightens toward a color in the middle

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 vec3 color                            ;
vec4 transition (vec2 uv) {
  return mix(
    getFromColor(uv) + vec4(progress*color, 1.0),
    getToColor(uv) + vec4((1.0-progress)*color, 1.0),
    progress
  );
}

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);
}