159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta/* 259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * Copyright (c) 2009-2010 jMonkeyEngine 359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * All rights reserved. 459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * 559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * Redistribution and use in source and binary forms, with or without 659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * modification, are permitted provided that the following conditions are 759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * met: 859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * 959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * * Redistributions of source code must retain the above copyright 1059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * notice, this list of conditions and the following disclaimer. 1159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * 1259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * * Redistributions in binary form must reproduce the above copyright 1359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * notice, this list of conditions and the following disclaimer in the 1459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * documentation and/or other materials provided with the distribution. 1559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * 1659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * * Neither the name of 'jMonkeyEngine' nor the names of its contributors 1759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * may be used to endorse or promote products derived from this software 1859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * without specific prior written permission. 1959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * 2059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 2159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 2259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 2359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 2459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 2559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 2659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 2759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 2859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 2959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 3059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 3159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta */ 3259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 3359b2e6871c65f58fdad78cd7229c292f6a177578Scott Bartapackage com.jme3.scene.control; 3459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 3559b2e6871c65f58fdad78cd7229c292f6a177578Scott Bartaimport com.jme3.bounding.BoundingBox; 3659b2e6871c65f58fdad78cd7229c292f6a177578Scott Bartaimport com.jme3.bounding.BoundingSphere; 3759b2e6871c65f58fdad78cd7229c292f6a177578Scott Bartaimport com.jme3.bounding.BoundingVolume; 3859b2e6871c65f58fdad78cd7229c292f6a177578Scott Bartaimport com.jme3.math.FastMath; 3959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 4059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta/** 4159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * <code>AreaUtils</code> is used to calculate the area of various objects, such as bounding volumes. These 4259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * functions are very loose approximations. 4359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * @author Joshua Slack 4459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * @version $Id: AreaUtils.java 4131 2009-03-19 20:15:28Z blaine.dev $ 4559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta */ 4659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 4759b2e6871c65f58fdad78cd7229c292f6a177578Scott Bartapublic class AreaUtils { 4859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 4959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta /** 5059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * calcScreenArea -- in Pixels 5159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * Aproximates the screen area of a bounding volume. If the volume isn't a 5259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * BoundingSphere, BoundingBox, or OrientedBoundingBox 0 is returned. 5359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * 5459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * @param bound The bounds to calculate the volume from. 5559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * @param distance The distance from camera to object. 5659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * @param screenWidth The width of the screen. 5759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * @return The area in pixels on the screen of the bounding volume. 5859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta */ 5959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta public static float calcScreenArea(BoundingVolume bound, float distance, float screenWidth) { 6059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta if (bound.getType() == BoundingVolume.Type.Sphere){ 6159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta return calcScreenArea((BoundingSphere) bound, distance, screenWidth); 6259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta }else if (bound.getType() == BoundingVolume.Type.AABB){ 6359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta return calcScreenArea((BoundingBox) bound, distance, screenWidth); 6459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 6559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta return 0.0f; 6659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 6759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 6859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta private static float calcScreenArea(BoundingSphere bound, float distance, float screenWidth) { 6959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta // Where is the center point and a radius point that lies in a plan parallel to the view plane? 7059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta// // Calc radius based on these two points and plug into circle area formula. 7159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta// Vector2f centerSP = null; 7259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta// Vector2f outerSP = null; 7359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta// float radiusSq = centerSP.subtract(outerSP).lengthSquared(); 7459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta float radius = (bound.getRadius() * screenWidth) / (distance * 2); 7559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta return radius * radius * FastMath.PI; 7659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 7759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 7859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta private static float calcScreenArea(BoundingBox bound, float distance, float screenWidth) { 7959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta // Calc as if we are a BoundingSphere for now... 8059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta float radiusSquare = bound.getXExtent() * bound.getXExtent() 8159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta + bound.getYExtent() * bound.getYExtent() 8259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta + bound.getZExtent() * bound.getZExtent(); 8359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta return ((radiusSquare * screenWidth * screenWidth) / (distance * distance * 4)) * FastMath.PI; 8459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 8559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta}