1 /******************************************************************************* 2 * Copyright (c) 2013, Daniel Murphy 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without modification, 6 * are permitted provided that the following conditions are met: 7 * * Redistributions of source code must retain the above copyright notice, 8 * this list of conditions and the following disclaimer. 9 * * Redistributions in binary form must reproduce the above copyright notice, 10 * this list of conditions and the following disclaimer in the documentation 11 * and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 16 * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 17 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 19 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 20 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 21 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 22 * POSSIBILITY OF SUCH DAMAGE. 23 ******************************************************************************/ 24 /** 25 * Created at 7:27:31 AM Jan 21, 2011 26 */ 27 package org.jbox2d.dynamics.joints; 28 29 import org.jbox2d.common.Vec2; 30 import org.jbox2d.dynamics.Body; 31 32 /** 33 * Wheel joint definition. This requires defining a line of motion using an axis and an anchor 34 * point. The definition uses local anchor points and a local axis so that the initial configuration 35 * can violate the constraint slightly. The joint translation is zero when the local anchor points 36 * coincide in world space. Using local anchors and a local axis helps when saving and loading a 37 * game. 38 * 39 * @author Daniel Murphy 40 */ 41 public class WheelJointDef extends JointDef { 42 43 /** 44 * The local anchor point relative to body1's origin. 45 */ 46 public final Vec2 localAnchorA = new Vec2(); 47 48 /** 49 * The local anchor point relative to body2's origin. 50 */ 51 public final Vec2 localAnchorB = new Vec2(); 52 53 /** 54 * The local translation axis in body1. 55 */ 56 public final Vec2 localAxisA = new Vec2(); 57 58 /** 59 * Enable/disable the joint motor. 60 */ 61 public boolean enableMotor; 62 63 /** 64 * The maximum motor torque, usually in N-m. 65 */ 66 public float maxMotorTorque; 67 68 /** 69 * The desired motor speed in radians per second. 70 */ 71 public float motorSpeed; 72 73 /** 74 * Suspension frequency, zero indicates no suspension 75 */ 76 public float frequencyHz; 77 78 /** 79 * Suspension damping ratio, one indicates critical damping 80 */ 81 public float dampingRatio; 82 83 public WheelJointDef() { 84 super(JointType.WHEEL); 85 localAxisA.set(1, 0); 86 enableMotor = false; 87 maxMotorTorque = 0f; 88 motorSpeed = 0f; 89 } 90 91 public void initialize(Body b1, Body b2, Vec2 anchor, Vec2 axis) { 92 bodyA = b1; 93 bodyB = b2; 94 b1.getLocalPointToOut(anchor, localAnchorA); 95 b2.getLocalPointToOut(anchor, localAnchorB); 96 bodyA.getLocalVectorToOut(axis, localAxisA); 97 } 98 } 99
