Directional Wipe.fs

Code

uniform sampler2D startImage;
uniform sampler2D endImage;
uniform float progress;
uniform vec2 direction;
uniform float smoothness;
precision mediump float;
/*{
    "CATEGORIES": [
        "Wipe"
    ],
    "CREDIT": "Automatically converted from https://www.github.com/gl-transitions/gl-transitions/tree/master/directionalwipe.glsl",
    "DESCRIPTION": "",
    "INPUTS": [
        {
            "NAME": "startImage",
            "TYPE": "image"
        },
        {
            "NAME": "endImage",
            "TYPE": "image"
        },
        {
            "DEFAULT": 0,
            "MAX": 1,
            "MIN": 0,
            "NAME": "progress",
            "TYPE": "float"
        },
        {
            "DEFAULT": [
                1,
                -1
            ],
            "MAX": [
                1,
                1
            ],
            "MIN": [
                -1,
                -1
            ],
            "NAME": "direction",
            "TYPE": "point2D"
        },
        {
            "DEFAULT": 0.5,
            "MAX": 1,
            "MIN": 0,
            "NAME": "smoothness",
            "TYPE": "float"
        }
    ],
    "ISFVSN": "2"
}
*/



vec4 getFromColor(vec2 inUV)	{
	return texture2D(startImage, inUV);
}
vec4 getToColor(vec2 inUV)	{
	return texture2D(endImage, inUV);
}



// Author: gre
// License: MIT

 
const vec2 center = vec2(0.5, 0.5);
 
vec4 transition (vec2 uv) {
  vec2 v = normalize(direction);
  v /= abs(v.x)+abs(v.y);
  float d = v.x * center.x + v.y * center.y;
  float m =
    (1.0-step(progress, 0.0)) * // there is something wrong with our formula that makes m not equals 0.0 with progress is 0.0
    (1.0 - smoothstep(-smoothness, 0.0, v.x * uv.x + v.y * uv.y - (d-0.5+progress*(1.+smoothness))));
  return mix(getFromColor(uv), getToColor(uv), m);
}



void main()	{
	gl_FragColor = transition((gl_FragCoord.xy / u_resolution.xy).xy);
}