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* Copyright (c) 2002-2008 LWJGL Project
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* * Redistributions of source code must retain the above copyright
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*
* * Redistributions in binary form must reproduce the above copyright
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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package org.lwjgl.examples.spaceinvaders;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.color.ColorSpace;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.ComponentColorModel;
import java.awt.image.DataBuffer;
import java.awt.image.DataBufferByte;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;
import java.io.IOException;
import java.net.URL;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.IntBuffer;
import java.util.HashMap;
import java.util.Hashtable;
import javax.swing.ImageIcon;
import org.lwjgl.BufferUtils;
import static org.lwjgl.opengl.GL11.*;
/**
* A utility class to load textures for OpenGL. This source is based
* on a texture that can be found in the Java Gaming (www.javagaming.org)
* Wiki. It has been simplified slightly for explicit 2D graphics use.
*
* OpenGL uses a particular image format. Since the images that are
* loaded from disk may not match this format this loader introduces
* a intermediate image which the source image is copied into. In turn,
* this image is used as source for the OpenGL texture.
*
* @author Kevin Glass
* @author Brian Matzon
*/
public class TextureLoader {
/** The table of textures that have been loaded in this loader */
private HashMap<String, Texture> table = new HashMap<String, Texture>();
/** The colour model including alpha for the GL image */
private ColorModel glAlphaColorModel;
/** The colour model for the GL image */
private ColorModel glColorModel;
/** Scratch buffer for texture ID's */
private IntBuffer textureIDBuffer = BufferUtils.createIntBuffer(1);
/**
* Create a new texture loader based on the game panel
*/
public TextureLoader() {
glAlphaColorModel = new ComponentColorModel(ColorSpace.getInstance(ColorSpace.CS_sRGB),
new int[] {8,8,8,8},
true,
false,
ComponentColorModel.TRANSLUCENT,
DataBuffer.TYPE_BYTE);
glColorModel = new ComponentColorModel(ColorSpace.getInstance(ColorSpace.CS_sRGB),
new int[] {8,8,8,0},
false,
false,
ComponentColorModel.OPAQUE,
DataBuffer.TYPE_BYTE);
}
/**
* Create a new texture ID
*
* @return A new texture ID
*/
private int createTextureID() {
glGenTextures(textureIDBuffer);
return textureIDBuffer.get(0);
}
/**
* Load a texture
*
* @param resourceName The location of the resource to load
* @return The loaded texture
* @throws IOException Indicates a failure to access the resource
*/
public Texture getTexture(String resourceName) throws IOException {
Texture tex = table.get(resourceName);
if (tex != null) {
return tex;
}
tex = getTexture(resourceName,
GL_TEXTURE_2D, // target
GL_RGBA, // dst pixel format
GL_LINEAR, // min filter (unused)
GL_LINEAR);
table.put(resourceName,tex);
return tex;
}
/**
* Load a texture into OpenGL from a image reference on
* disk.
*
* @param resourceName The location of the resource to load
* @param target The GL target to load the texture against
* @param dstPixelFormat The pixel format of the screen
* @param minFilter The minimising filter
* @param magFilter The magnification filter
* @return The loaded texture
* @throws IOException Indicates a failure to access the resource
*/
public Texture getTexture(String resourceName,
int target,
int dstPixelFormat,
int minFilter,
int magFilter) throws IOException {
int srcPixelFormat;
// create the texture ID for this texture
int textureID = createTextureID();
Texture texture = new Texture(target,textureID);
// bind this texture
glBindTexture(target, textureID);
BufferedImage bufferedImage = loadImage(resourceName);
texture.setWidth(bufferedImage.getWidth());
texture.setHeight(bufferedImage.getHeight());
if (bufferedImage.getColorModel().hasAlpha()) {
srcPixelFormat = GL_RGBA;
} else {
srcPixelFormat = GL_RGB;
}
// convert that image into a byte buffer of texture data
ByteBuffer textureBuffer = convertImageData(bufferedImage,texture);
if (target == GL_TEXTURE_2D) {
glTexParameteri(target, GL_TEXTURE_MIN_FILTER, minFilter);
glTexParameteri(target, GL_TEXTURE_MAG_FILTER, magFilter);
}
// produce a texture from the byte buffer
glTexImage2D(target,
0,
dstPixelFormat,
get2Fold(bufferedImage.getWidth()),
get2Fold(bufferedImage.getHeight()),
0,
srcPixelFormat,
GL_UNSIGNED_BYTE,
textureBuffer );
return texture;
}
/**
* Get the closest greater power of 2 to the fold number
*
* @param fold The target number
* @return The power of 2
*/
private static int get2Fold(int fold) {
int ret = 2;
while (ret < fold) {
ret *= 2;
}
return ret;
}
/**
* Convert the buffered image to a texture
*
* @param bufferedImage The image to convert to a texture
* @param texture The texture to store the data into
* @return A buffer containing the data
*/
private ByteBuffer convertImageData(BufferedImage bufferedImage,Texture texture) {
ByteBuffer imageBuffer;
WritableRaster raster;
BufferedImage texImage;
int texWidth = 2;
int texHeight = 2;
// find the closest power of 2 for the width and height
// of the produced texture
while (texWidth < bufferedImage.getWidth()) {
texWidth *= 2;
}
while (texHeight < bufferedImage.getHeight()) {
texHeight *= 2;
}
texture.setTextureHeight(texHeight);
texture.setTextureWidth(texWidth);
// create a raster that can be used by OpenGL as a source
// for a texture
if (bufferedImage.getColorModel().hasAlpha()) {
raster = Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE,texWidth,texHeight,4,null);
texImage = new BufferedImage(glAlphaColorModel,raster,false,new Hashtable());
} else {
raster = Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE,texWidth,texHeight,3,null);
texImage = new BufferedImage(glColorModel,raster,false,new Hashtable());
}
// copy the source image into the produced image
Graphics g = texImage.getGraphics();
g.setColor(new Color(0f,0f,0f,0f));
g.fillRect(0,0,texWidth,texHeight);
g.drawImage(bufferedImage,0,0,null);
// build a byte buffer from the temporary image
// that be used by OpenGL to produce a texture.
byte[] data = ((DataBufferByte) texImage.getRaster().getDataBuffer()).getData();
imageBuffer = ByteBuffer.allocateDirect(data.length);
imageBuffer.order(ByteOrder.nativeOrder());
imageBuffer.put(data, 0, data.length);
imageBuffer.flip();
return imageBuffer;
}
/**
* Load a given resource as a buffered image
*
* @param ref The location of the resource to load
* @return The loaded buffered image
* @throws IOException Indicates a failure to find a resource
*/
private BufferedImage loadImage(String ref) throws IOException {
URL url = TextureLoader.class.getClassLoader().getResource(ref);
if (url == null) {
throw new IOException("Cannot find: " + ref);
}
// due to an issue with ImageIO and mixed signed code
// we are now using good oldfashioned ImageIcon to load
// images and the paint it on top of a new BufferedImage
Image img = new ImageIcon(url).getImage();
BufferedImage bufferedImage = new BufferedImage(img.getWidth(null), img.getHeight(null), BufferedImage.TYPE_INT_RGB);
Graphics g = bufferedImage.getGraphics();
g.drawImage(img, 0, 0, null);
g.dispose();
return bufferedImage;
}
}