/**
 * Simple fade between 2 images
 */
export default class Fade implements FLib.GLImageTransition.Preset {

    get fsSource(): string {
        return `
            #ifdef GL_ES
            precision mediump float;
            #endif

            varying highp vec2 vTextureCoord;

            uniform sampler2D uSampler;
            uniform sampler2D uSampler2;
            uniform float uProgress;
            uniform float uTime;
            uniform float uDeltaTime;

            void main(void) {
                vec3 t1Color = texture2D(uSampler, vTextureCoord).rgb;
                vec3 t2Color = texture2D(uSampler2, vTextureCoord).rgb;

                vec3 color = mix( t1Color, t2Color, uProgress );

                gl_FragColor = vec4( color, 1.0 );
            }
        `;
    }
}