#version 150
//OVE shader_name: Color Distance
//OVE shader_description: by gre (License: MIT)
// ported by gre from https://gist.github.com/P-Seebauer/2a5fa2f77c883dd661f9

//OVE name: Power
//OVE type: FLOAT
//OVE flag: NOT_CONNECTABLE
//OVE min: 0
//OVE default: 5
//OVE description:
uniform float power;


//OVE end

#define LINEAR_CURVE 0
#define EXPONENTIAL_CURVE 1
#define LOGARITHMIC_CURVE 2

uniform sampler2D out_block_in;
uniform sampler2D in_block_in;
uniform bool out_block_in_enabled;
uniform bool in_block_in_enabled;
uniform int curve_in;

/* animated from 0 to 1 */
uniform float ove_tprog_all;

in vec2 ove_texcoord;
out vec4 frag_color;

vec4 getFromColor( vec2 p)
{
  return texture( in_block_in, p);
}

vec4 getToColor( vec2 p)
{
  return texture( out_block_in, p);
}

float TransformCurve(float linear) {
  if (curve_in == EXPONENTIAL_CURVE) {
    return linear * linear;
  } else if (curve_in == LOGARITHMIC_CURVE) {
    return sqrt(linear);
  } else {
    return linear;
  }
}

vec4 transition(vec2 p, float progress) {
  vec4 fTex = getFromColor(p);
  vec4 tTex = getToColor(p);
  float m = step(distance(fTex, tTex), progress);
  return mix(
    mix(fTex, tTex, m),
    tTex,
    pow(progress, power)
  );
}


void main(void) {
    frag_color = transition( ove_texcoord.xy, TransformCurve(1.0 - ove_tprog_all));
}