TextureLoader.java

package complexion.client;

import static org.lwjgl.opengl.GL11.GL_NEAREST;
import static org.lwjgl.opengl.GL11.GL_RGBA;
import static org.lwjgl.opengl.GL11.GL_RGBA8;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_2D;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_MAG_FILTER;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_MIN_FILTER;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_WRAP_S;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_WRAP_T;
import static org.lwjgl.opengl.GL11.GL_UNSIGNED_BYTE;
import static org.lwjgl.opengl.GL11.glBindTexture;
import static org.lwjgl.opengl.GL11.glGenTextures;
import static org.lwjgl.opengl.GL11.glTexImage2D;
import static org.lwjgl.opengl.GL11.glTexParameteri;

import java.awt.image.BufferedImage;
import java.nio.ByteBuffer;

import org.lwjgl.BufferUtils;
import org.lwjgl.opengl.GL12;

/**
 * Static class responsible for texture loading.
 * Code taken from http://stackoverflow.com/questions/10801016/lwjgl-textures-and-strings
 */
public class TextureLoader {
	private static final int BYTES_PER_PIXEL = 4;// 3 for RGB, 4 for RGBA

	/**
	 * Takes a BufferedImage, loads it into the OpenGL texture cache,
	 * and returns the texture ID.
	 */
	public static int loadTexture(BufferedImage image) {

		int[] pixels = new int[image.getWidth() * image.getHeight()];
		image.getRGB(0, 0, image.getWidth(), image.getHeight(), pixels, 0,
				image.getWidth());

		ByteBuffer buffer = BufferUtils.createByteBuffer(image.getWidth()
				* image.getHeight() * BYTES_PER_PIXEL); // 4 for RGBA, 3 for RGB

		for (int y = 0; y < image.getHeight(); y++) {
			for (int x = 0; x < image.getWidth(); x++) {
				int pixel = pixels[y * image.getWidth() + x];
				buffer.put((byte) ((pixel >> 16) & 0xFF)); // Red component
				buffer.put((byte) ((pixel >> 8) & 0xFF)); // Green component
				buffer.put((byte) (pixel & 0xFF)); // Blue component
				buffer.put((byte) ((pixel >> 24) & 0xFF)); // Alpha component.
															// Only for RGBA
			}
		}

		buffer.flip(); // FOR THE LOVE OF GOD DO NOT FORGET THIS

		// You now have a ByteBuffer filled with the color data of each pixel.
		// Now just create a texture ID and bind it. Then you can load it using
		// whatever OpenGL method you want, for example:

		int textureID = glGenTextures(); // Generate texture ID
		glBindTexture(GL_TEXTURE_2D, textureID); // Bind texture ID

		// Setup wrap mode
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL12.GL_CLAMP_TO_EDGE);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL12.GL_CLAMP_TO_EDGE);

		// Setup texture scaling filtering
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

		// Send texel data to OpenGL
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, image.getWidth(),
				image.getHeight(), 0, GL_RGBA, GL_UNSIGNED_BYTE, buffer);

		// Return the texture ID so we can bind it later again
		return textureID;
	}

}