NullImage.java

/*******************************************************************************
 * Copyright (c) 2015, 2016
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *******************************************************************************/
package jsettlers.graphics.image;

import java.nio.ShortBuffer;

import go.graphics.GLDrawContext;
import jsettlers.common.Color;
import jsettlers.graphics.reader.ImageMetadata;

/**
 * This is a null image.
 * <p>
 * It may be returned by image methods if the requested image is not available.
 * 
 * @author Michael Zangl
 */
public final class NullImage extends SingleImage {
	private static final float NULL_IMAGE_ALPHA = 0.5f;
	private static final short[] NULL_DATA = new short[] { 0 };
	private static final int HALFSIZE = 3;
	private static final ImageMetadata NULL_IMAGE_METADATA = new ImageMetadata();

	static {
		NULL_IMAGE_METADATA.width = 1;
		NULL_IMAGE_METADATA.height = 1;
		NULL_IMAGE_METADATA.offsetX = 0;
		NULL_IMAGE_METADATA.offsetY = 0;
	}

	private static NullImage instance;
	private static LandscapeImage landscapeinstance = null;

	/**
	 * Gets an instance of the null image.
	 * 
	 * @return An instance.
	 */
	public static NullImage getInstance() {
		if (instance == null) {
			instance = new NullImage();
		}
		return instance;
	}

	private NullImage() {
		super(ShortBuffer.allocate(1), 1, 1, 0, 0);
	}

	@Override
	public void draw(GLDrawContext gl, Color color) {
		gl.color(1, 1, 1, NULL_IMAGE_ALPHA);
		gl.fillQuad(-HALFSIZE, -HALFSIZE, HALFSIZE, HALFSIZE);

		gl.color(1, 0, 0, 1);
		gl.drawLine(new float[] {
				-HALFSIZE,
				-HALFSIZE,
				0,
				+HALFSIZE,
				-HALFSIZE,
				0,
				+HALFSIZE,
				+HALFSIZE,
				0,
				-HALFSIZE,
				+HALFSIZE,
				0,
		}, true);
	}

	private static GuiImage guiinstance;

	/**
	 * Gets an empty landscape image.
	 * 
	 * @return The imge instance.
	 */
	public static LandscapeImage getForLandscape() {
		if (landscapeinstance == null) {
			landscapeinstance = new LandscapeImage(NULL_IMAGE_METADATA, NULL_DATA);
		}
		return landscapeinstance;
	}

	/**
	 * Gets an empty gui image.
	 * 
	 * @return The imge instance.
	 */
	public static GuiImage getForGui() {
		if (guiinstance == null) {
			guiinstance = new GuiImage(NULL_IMAGE_METADATA, NULL_DATA);
		}
		return guiinstance;
	}
}