#version 330 core
out vec4 FragColor;
in vec2 TexCoord;

uniform sampler2D inputImageTexture;
uniform sampler2D inputImageTexture2;
uniform float mixturePercent;
uniform int   directionType;

// Both clips stay put; a hard edge sweeps across the screen revealing the
// incoming clip behind it. directionType convention same as transition_slide.fs.
void main() {
    if (directionType == 2) {
        FragColor = (TexCoord.y > mixturePercent)
            ? texture(inputImageTexture,  TexCoord)
            : texture(inputImageTexture2, TexCoord);
    } else if (directionType == 1) {
        FragColor = (TexCoord.x > mixturePercent)
            ? texture(inputImageTexture,  TexCoord)
            : texture(inputImageTexture2, TexCoord);
    } else if (directionType == 0) {
        FragColor = (TexCoord.y < (1.0 - mixturePercent))
            ? texture(inputImageTexture,  TexCoord)
            : texture(inputImageTexture2, TexCoord);
    } else if (directionType == 3) {
        FragColor = (TexCoord.x < (1.0 - mixturePercent))
            ? texture(inputImageTexture,  TexCoord)
            : texture(inputImageTexture2, TexCoord);
    } else {
        vec4 a = texture(inputImageTexture,  TexCoord);
        vec4 b = texture(inputImageTexture2, TexCoord);
        FragColor = mix(a, b, mixturePercent);
    }
}