/*
 * Copyright (c) 2009-2010 jMonkeyEngine
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
 *   may be used to endorse or promote products derived from this software
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.aionemu.gameserver.geoEngine.scene;

import com.aionemu.gameserver.geoEngine.math.Vector3f;

/**
 * An eight sided box.
 * <p>
 * A {@code Box} is defined by a minimal point and a maximal point. The eight vertices that make the box are then
 * computed, they are computed in such a way as to generate an axis-aligned box.
 * <p>
 * This class does not control how the geometry data is generated, see {@link Box} for that.
 * 
 * @author <a href="mailto:ianp@ianp.org">Ian Phillips</a>
 * @version $Revision: 4131 $, $Date: 2009-03-19 16:15:28 -0400 (Thu, 19 Mar 2009) $
 */
public abstract class AbstractBox extends Mesh {

	public final Vector3f center = new Vector3f(0f, 0f, 0f);

	public float xExtent, yExtent, zExtent;

	public AbstractBox() {
		super();
	}

	/**
	 * Gets the array or vectors representing the 8 vertices of the box.
	 * 
	 * @return a newly created array of vertex vectors.
	 */
	protected final Vector3f[] computeVertices() {
		Vector3f[] axes = { Vector3f.UNIT_X.mult(xExtent), Vector3f.UNIT_Y.mult(yExtent), Vector3f.UNIT_Z.mult(zExtent) };
		return new Vector3f[] { center.subtract(axes[0]).subtractLocal(axes[1]).subtractLocal(axes[2]),
			center.add(axes[0]).subtractLocal(axes[1]).subtractLocal(axes[2]), center.add(axes[0]).addLocal(axes[1]).subtractLocal(axes[2]),
			center.subtract(axes[0]).addLocal(axes[1]).subtractLocal(axes[2]), center.add(axes[0]).subtractLocal(axes[1]).addLocal(axes[2]),
			center.subtract(axes[0]).subtractLocal(axes[1]).addLocal(axes[2]), center.add(axes[0]).addLocal(axes[1]).addLocal(axes[2]),
			center.subtract(axes[0]).addLocal(axes[1]).addLocal(axes[2]) };
	}

	/**
	 * Convert the indices into the list of vertices that define the box's geometry.
	 */
	protected abstract void duUpdateGeometryIndices();

	/**
	 * Update the normals of each of the box's planes.
	 */
	protected abstract void duUpdateGeometryNormals();

	/**
	 * Update the position of the vertices that define the box.
	 * <p>
	 * These eight points are determined from the minimum and maximum point.
	 */
	protected abstract void duUpdateGeometryVertices();

	/**
	 * Get the center point of this box.
	 */
	public final Vector3f getCenter() {
		return center;
	}

	/**
	 * Get the x-axis size (extent) of this box.
	 */
	public final float getXExtent() {
		return xExtent;
	}

	/**
	 * Get the y-axis size (extent) of this box.
	 */
	public final float getYExtent() {
		return yExtent;
	}

	/**
	 * Get the z-axis size (extent) of this box.
	 */
	public final float getZExtent() {
		return zExtent;
	}

	/**
	 * Rebuilds the box after a property has been directly altered.
	 * <p>
	 * For example, if you call {@code getXExtent().x = 5.0f} then you will need to call this method afterwards in order
	 * to update the box.
	 */
	public final void updateGeometry() {
		duUpdateGeometryVertices();
		duUpdateGeometryNormals();
		duUpdateGeometryIndices();
	}

	/**
	 * Rebuilds this box based on a new set of parameters.
	 * <p>
	 * Note that the actual sides will be twice the given extent values because the box extends in both directions from
	 * the center for each extent.
	 * 
	 * @param center
	 *          the center of the box.
	 * @param x
	 *          the x extent of the box, in each directions.
	 * @param y
	 *          the y extent of the box, in each directions.
	 * @param z
	 *          the z extent of the box, in each directions.
	 */
	public final void updateGeometry(Vector3f center, float x, float y, float z) {
		if (center != null) {
			this.center.set(center);
		}
		this.xExtent = x;
		this.yExtent = y;
		this.zExtent = z;
		updateGeometry();
	}

	/**
	 * Rebuilds this box based on a new set of parameters.
	 * <p>
	 * The box is updated so that the two opposite corners are {@code minPoint} and {@code maxPoint}, the other corners
	 * are created from those two positions.
	 * 
	 * @param minPoint
	 *          the new minimum point of the box.
	 * @param maxPoint
	 *          the new maximum point of the box.
	 */
	public final void updateGeometry(Vector3f minPoint, Vector3f maxPoint) {
		center.set(maxPoint).addLocal(minPoint).multLocal(0.5f);
		float x = maxPoint.x - center.x;
		float y = maxPoint.y - center.y;
		float z = maxPoint.z - center.z;
		updateGeometry(center, x, y, z);
	}

}