#version 150
//OVE shader_name: burn
//OVE shader_description: by gre (License: MIT)

//OVE name: Color
//OVE type: COLOR
//OVE default: RGBA(0.9, 0.4, 0.2,  1)
//OVE description: 
uniform vec4 color_in;
//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 uv, float progress) {
  return mix(
    getFromColor(uv) + progress*color_in,
    getToColor(uv) + (1.0-progress)*color_in,
    progress
  );
}



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