/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
<languageVersion : 1.0;>
kernel WipeLeft
<   namespace : "flex";
    vendor : "Adobe";
    version : 1;
    description : "Wipe left between two images for Flex effects";
>
{
    // first input is unused in AnimateTransitionShader effect
    input image4 src0;
    input image4 from;
    input image4 to;
    output pixel4 dst;

    parameter float progress<
        minValue: 0.00;
        maxValue: 1.00;
        defaultValue: 0.0;
    >;

    parameter float width<
        minValue: 0.0;
        maxValue: 1024.0;
        defaultValue: 576.0;
    >;

    parameter float height<
        minValue: 0.00;
        maxValue: 1024.0;
        defaultValue: 384.0;
    >;
    
    void
    evaluatePixel()
    {
        float2 coord = outCoord();
        
        // Use src0 in a branch we won't reach just to defeat the 
        // optimizer from removing the input parameter
        if ((width * (1.0 - progress)) >= coord.x) 
            dst = sampleNearest(from, coord);
        else if (progress < 100.0)
            dst = sampleNearest(to, coord);
        else
            dst = sampleNearest(src0, coord);
        // workaround for Flash filter bug that replicates last column/row
        if (coord.x >= width || coord.y >= height)
            dst.a = 0.0;
    }
}