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.terrain.geomipmap.picking; 3459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 3559b2e6871c65f58fdad78cd7229c292f6a177578Scott Bartaimport com.jme3.math.Ray; 3659b2e6871c65f58fdad78cd7229c292f6a177578Scott Bartaimport com.jme3.math.Vector2f; 3759b2e6871c65f58fdad78cd7229c292f6a177578Scott Bartaimport com.jme3.math.Vector3f; 3859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 3959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta/** 4059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * Works on the XZ plane, with positive Y as up. 4159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * 4259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * @author Joshua Slack 4359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta * @author Brent Owens 4459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta */ 4559b2e6871c65f58fdad78cd7229c292f6a177578Scott Bartapublic class BresenhamYUpGridTracer { 4659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 4759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta protected Vector3f gridOrigin = new Vector3f(); 4859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta protected Vector3f gridSpacing = new Vector3f(); 4959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta protected Vector2f gridLocation = new Vector2f(); 5059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta protected Vector3f rayLocation = new Vector3f(); 5159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta protected Ray walkRay = new Ray(); 5259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 5359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta protected Direction stepDirection = Direction.None; 5459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta protected float rayLength; 5559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 5659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta public static enum Direction { 5759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta None, PositiveX, NegativeX, PositiveY, NegativeY, PositiveZ, NegativeZ; 5859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta }; 5959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 6059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta // a "near zero" value we will use to determine if the walkRay is 6159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta // perpendicular to the grid. 6259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta protected static float TOLERANCE = 0.0000001f; 6359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 6459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta private int stepXDirection; 6559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta private int stepZDirection; 6659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 6759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta // from current position along ray 6859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta private float distToNextXIntersection, distToNextZIntersection; 6959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta private float distBetweenXIntersections, distBetweenZIntersections; 7059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 7159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta public void startWalk(final Ray walkRay) { 7259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta // store ray 7359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta this.walkRay.set(walkRay); 7459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 7559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta // simplify access to direction 7659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta Vector3f direction = this.walkRay.getDirection(); 7759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 7859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta // Move start point to grid space 7959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta Vector3f start = this.walkRay.getOrigin().subtract(gridOrigin); 8059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 8159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta gridLocation.x = (int) (start.x / gridSpacing.x); 8259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta gridLocation.y = (int) (start.z / gridSpacing.z); 8359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 8459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta Vector3f ooDirection = new Vector3f(1.0f / direction.x, 1,1.0f / direction.z); 8559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 8659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta // Check which direction on the X world axis we are moving. 8759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta if (direction.x > TOLERANCE) { 8859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta distToNextXIntersection = ((gridLocation.x + 1) * gridSpacing.x - start.x) * ooDirection.x; 8959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta distBetweenXIntersections = gridSpacing.x * ooDirection.x; 9059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta stepXDirection = 1; 9159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } else if (direction.x < -TOLERANCE) { 9259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta distToNextXIntersection = (start.x - (gridLocation.x * gridSpacing.x)) * -direction.x; 9359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta distBetweenXIntersections = -gridSpacing.x * ooDirection.x; 9459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta stepXDirection = -1; 9559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } else { 9659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta distToNextXIntersection = Float.MAX_VALUE; 9759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta distBetweenXIntersections = Float.MAX_VALUE; 9859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta stepXDirection = 0; 9959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 10059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 10159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta // Check which direction on the Z world axis we are moving. 10259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta if (direction.z > TOLERANCE) { 10359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta distToNextZIntersection = ((gridLocation.y + 1) * gridSpacing.z - start.z) * ooDirection.z; 10459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta distBetweenZIntersections = gridSpacing.z * ooDirection.z; 10559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta stepZDirection = 1; 10659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } else if (direction.z < -TOLERANCE) { 10759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta distToNextZIntersection = (start.z - (gridLocation.y * gridSpacing.z)) * -direction.z; 10859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta distBetweenZIntersections = -gridSpacing.z * ooDirection.z; 10959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta stepZDirection = -1; 11059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } else { 11159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta distToNextZIntersection = Float.MAX_VALUE; 11259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta distBetweenZIntersections = Float.MAX_VALUE; 11359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta stepZDirection = 0; 11459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 11559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 11659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta // Reset some variables 11759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta rayLocation.set(start); 11859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta rayLength = 0.0f; 11959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta stepDirection = Direction.None; 12059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 12159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 12259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta public void next() { 12359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta // Walk us to our next location based on distances to next X or Z grid 12459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta // line. 12559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta if (distToNextXIntersection < distToNextZIntersection) { 12659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta rayLength = distToNextXIntersection; 12759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta gridLocation.x += stepXDirection; 12859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta distToNextXIntersection += distBetweenXIntersections; 12959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta switch (stepXDirection) { 13059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta case -1: 13159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta stepDirection = Direction.NegativeX; 13259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta break; 13359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta case 0: 13459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta stepDirection = Direction.None; 13559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta break; 13659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta case 1: 13759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta stepDirection = Direction.PositiveX; 13859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta break; 13959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 14059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } else { 14159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta rayLength = distToNextZIntersection; 14259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta gridLocation.y += stepZDirection; 14359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta distToNextZIntersection += distBetweenZIntersections; 14459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta switch (stepZDirection) { 14559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta case -1: 14659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta stepDirection = Direction.NegativeZ; 14759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta break; 14859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta case 0: 14959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta stepDirection = Direction.None; 15059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta break; 15159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta case 1: 15259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta stepDirection = Direction.PositiveZ; 15359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta break; 15459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 15559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 15659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 15759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta rayLocation.set(walkRay.direction).multLocal(rayLength).addLocal(walkRay.origin); 15859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 15959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 16059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta public Direction getLastStepDirection() { 16159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta return stepDirection; 16259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 16359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 16459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta public boolean isRayPerpendicularToGrid() { 16559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta return stepXDirection == 0 && stepZDirection == 0; 16659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 16759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 16859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 16959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta public Vector2f getGridLocation() { 17059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta return gridLocation; 17159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 17259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 17359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta public Vector3f getGridOrigin() { 17459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta return gridOrigin; 17559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 17659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 17759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta public Vector3f getGridSpacing() { 17859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta return gridSpacing; 17959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 18059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 18159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 18259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta public void setGridLocation(Vector2f gridLocation) { 18359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta this.gridLocation = gridLocation; 18459b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 18559b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 18659b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta public void setGridOrigin(Vector3f gridOrigin) { 18759b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta this.gridOrigin = gridOrigin; 18859b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 18959b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta 19059b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta public void setGridSpacing(Vector3f gridSpacing) { 19159b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta this.gridSpacing = gridSpacing; 19259b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta } 19359b2e6871c65f58fdad78cd7229c292f6a177578Scott Barta} 194