MinecraftForge/src/test/java/net/minecraftforge/debug/TextureDump.java

package net.minecraftforge.debug;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.nio.IntBuffer;

import javax.imageio.ImageIO;

import net.minecraftforge.fml.common.FMLLog;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.common.event.FMLPreInitializationEvent;
import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;
import org.lwjgl.BufferUtils;
import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.GL12;

import net.minecraft.client.renderer.texture.TextureMap;
import net.minecraftforge.client.event.TextureStitchEvent;
import net.minecraftforge.common.MinecraftForge;

@Mod(modid = TextureDump.MODID, name = "Forge Texture Atlas Dump", version = TextureDump.VERSION, clientSideOnly = true)
public class TextureDump
{
	public static final String MODID = "forge_texture_dump";
	public static final String VERSION = "1.0";

	public static final boolean ENABLE = true;

	@Mod.EventHandler
	public void preInit(FMLPreInitializationEvent event)
	{
		if (ENABLE)
		{
			MinecraftForge.EVENT_BUS.register(this);
		}
	}

	@SubscribeEvent
	public void postTextureStitch(TextureStitchEvent.Post e) throws Exception
	{
		TextureMap map = e.getMap();
		String name = map.getBasePath().replace('/', '_');
		int mip = map.getMipmapLevels();
		saveGlTexture(name, map.getGlTextureId(), mip);
	}

	public static void saveGlTexture(String name, int textureId, int mipmapLevels)
	{
		GL11.glBindTexture(GL11.GL_TEXTURE_2D, textureId);

		GL11.glPixelStorei(GL11.GL_PACK_ALIGNMENT, 1);
		GL11.glPixelStorei(GL11.GL_UNPACK_ALIGNMENT, 1);

		for (int level = 0; level <= mipmapLevels; level++)
		{
			int width = GL11.glGetTexLevelParameteri(GL11.GL_TEXTURE_2D, level, GL11.GL_TEXTURE_WIDTH);
			int height = GL11.glGetTexLevelParameteri(GL11.GL_TEXTURE_2D, level, GL11.GL_TEXTURE_HEIGHT);
			int size = width * height;

			BufferedImage bufferedimage = new BufferedImage(width, height, 2);
			File output = new File("texture_atlas_dump_" + name + "_mipmap_" + level + ".png");

			IntBuffer buffer = BufferUtils.createIntBuffer(size);
			int[] data = new int[size];

			GL11.glGetTexImage(GL11.GL_TEXTURE_2D, level, GL12.GL_BGRA, GL12.GL_UNSIGNED_INT_8_8_8_8_REV, buffer);
			buffer.get(data);
			bufferedimage.setRGB(0, 0, width, height, data, 0, width);

			try
			{
				ImageIO.write(bufferedimage, "png", output);
				FMLLog.info("[TextureDump] Exported png to: %s", output.getAbsolutePath());
			}
			catch (IOException ioexception)
			{
				FMLLog.info("[TextureDump] Unable to write: ", ioexception);
			}
		}
	}
}