1/*
2 * Copyright (c) 2009-2010 jMonkeyEngine
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met:
8 *
9 * * Redistributions of source code must retain the above copyright
10 *   notice, this list of conditions and the following disclaimer.
11 *
12 * * Redistributions in binary form must reproduce the above copyright
13 *   notice, this list of conditions and the following disclaimer in the
14 *   documentation and/or other materials provided with the distribution.
15 *
16 * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
17 *   may be used to endorse or promote products derived from this software
18 *   without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
24 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
26 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
27 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
28 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
29 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
30 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33package com.jme3.texture.plugins;
34
35import com.jme3.texture.Image;
36import com.jme3.util.BufferUtils;
37import java.nio.ByteBuffer;
38
39/**
40 * ImageFlipper is a utility class used to flip images across the Y axis.
41 * Due to the standard of where the image origin is between OpenGL and
42 * other software, this class is required.
43 *
44 * @author Kirill Vainer
45 */
46public class ImageFlipper {
47
48    public static void flipImage(Image img, int index){
49        if (img.getFormat().isCompressed())
50            throw new UnsupportedOperationException("Flipping compressed " +
51                                                    "images is unsupported.");
52
53        int w = img.getWidth();
54        int h = img.getHeight();
55        int halfH = h / 2;
56
57        // bytes per pixel
58        int bpp = img.getFormat().getBitsPerPixel() / 8;
59        int scanline = w * bpp;
60
61        ByteBuffer data = img.getData(index);
62        ByteBuffer temp = BufferUtils.createByteBuffer(scanline);
63
64        data.rewind();
65        for (int y = 0; y < halfH; y++){
66            int oppY = h - y - 1;
67            // read in scanline
68            data.position(y * scanline);
69            data.limit(data.position() + scanline);
70
71            temp.rewind();
72            temp.put(data);
73
74        }
75    }
76
77}
78