TextureData.java

/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 * 
 * Licensed 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.
 ******************************************************************************/

package com.badlogic.gdx.graphics;

import com.badlogic.gdx.graphics.Pixmap.Format;
import com.badlogic.gdx.graphics.glutils.ETC1TextureData;
import com.badlogic.gdx.graphics.glutils.FileTextureData;
import com.badlogic.gdx.graphics.glutils.MipMapGenerator;

/**
 * Used by a {@link Texture} to load the pixel data. A TextureData can either return a {@link Pixmap} or upload the
 * pixel data itself. It signals it's type via {@link #getType()} to the Texture that's using it. The Texture will then
 * either invoke {@link #consumePixmap()} or {@link #consumeCompressedData()}. These are the first methods to be called
 * by Texture. After that the Texture will invoke the other methods to find out about the size of the image data, the
 * format, whether mipmaps should be generated and whether the TextureData is able to manage the pixel data if the
 * OpenGL ES context is lost.</p>
 * 
 * In case the TextureData implementation has the type {@link TextureDataType#Compressed}, the implementation has to
 * generate the mipmaps itself if necessary. See {@link MipMapGenerator}.</p>
 * 
 * Before a call to either {@link #consumePixmap()} or {@link #consumeCompressedData()}, Texture will bind the OpenGL ES
 * texture.</p>
 * 
 * Look at {@link FileTextureData} and {@link ETC1TextureData} for example implementations of this interface.
 * 
 * @author mzechner
 */
public interface TextureData {
	/**
	 * The type of this {@link TextureData}.
	 * 
	 * @author mzechner
	 */
	public String getFileName();

	public enum TextureDataType {
		Pixmap, Compressed, Float,
	}

	/** @return the {@link TextureDataType} */
	public TextureDataType getType();

	/** @return whether the TextureData is prepared or not. */
	public boolean isPrepared();

	/**
	 * Prepares the TextureData for a call to {@link #consumePixmap()} or {@link #consumeCompressedData()}. This method
	 * can be called from a non OpenGL thread and should thus not interact with OpenGL.
	 */
	public void prepare();

	/**
	 * Returns the {@link Pixmap} for upload by Texture. A call to {@link #prepare()} must preceed a call to this
	 * method. Any internal datastructures created in {@link #prepare()} should be disposed of here.
	 * 
	 * @return the pixmap.
	 */
	public Pixmap consumePixmap();

	/**
	 * @return whether the caller of {@link #consumePixmap()} should dispose the Pixmap returned by
	 *         {@link #consumePixmap()}
	 */
	public boolean disposePixmap();

	/**
	 * Uploads the pixel data to the OpenGL ES texture. The caller must bind an OpenGL ES texture. A call to
	 * {@link #prepare()} must preceed a call to this method. Any internal datastructures created in {@link #prepare()}.
	 */
	public void consumeCompressedData();

	/** @return the width of the pixel data */
	public int getWidth();

	/** @return the height of the pixel data */
	public int getHeight();

	/** @return the {@link Format} of the pixel data */
	public Format getFormat();

	/** @return whether to generate mipmaps or not. */
	public boolean useMipMaps();

	/** @return whether this implementation can cope with a EGL context loss. */
	public boolean isManaged();
}