#version 150
//OVE shader_name: Displacement
//OVE shader_description: by Travis Fischer (Licence MIT)


//OVE name: Displacement map
//OVE type: TEXTURE
//OVE flag: NOT_KEYFRAMABLE
//OVE description: 
uniform sampler2D displacementMap;

//OVE name: Strength
//OVE type: FLOAT
//OVE flag: NOT_CONNECTABLE
//OVE min: 0.0
//OVE max: 3.0
//OVE default: 0.5
//OVE description: 
uniform float strength;

//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;

float progress;

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 displacement = texture2D(displacementMap, uv).r * strength;

  vec2 uvFrom = vec2(uv.x + progress * displacement, uv.y);
  vec2 uvTo = vec2(uv.x - (1.0 - progress) * displacement, uv.y);

  return mix(
    getFromColor(uvFrom),
    getToColor(uvTo),
    progress
  );

}


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