/*
* Phys2D - a 2D physics engine based on the work of Erin Catto. The
* original source remains:
*
* Copyright (c) 2006 Erin Catto http://www.gphysics.com
*
* This source is provided under the terms of the BSD License.
*
* Copyright (c) 2006, Phys2D
* 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 the Phys2D/New Dawn Software 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 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
* TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*/
package net.phys2d.raw;
import net.phys2d.math.Vector2f;
/**
* A joint between two bodies. The joint affects the impulses applied to
* each body each step constraining the movement. This joint is anchored
* on the opposing bodies centre
*
* @author Kevin Glass
*/
public strictfp class FixedJoint implements Joint {
/** The next ID to be used */
public static int NEXT_ID = 0;
/** The first body attached to the joint */
private Body body1;
/** The second body attached to the joint */
private Body body2;
/** The ID of this joint */
private int id;
/** The first joint fixing the position in one direction */
private BasicJoint joint1;
/** The second joint fixing the position in one direction */
private BasicJoint joint2;
/**
* Create a joint holding two bodies together
*
* @param b1 The first body attached to the joint
* @param b2 The second body attached to the joint
*/
public FixedJoint(Body b1, Body b2) {
id = NEXT_ID++;
set(b1,b2);
}
/**
* Set the relaxtion value on this joint. This value determines
* how loose the joint will be
*
* @param relaxation The relaxation value
*/
public void setRelaxation(float relaxation) {
joint1.setRelaxation(relaxation);
joint2.setRelaxation(relaxation);
}
/**
* Get the first body attached to this joint
*
* @return The first body attached to this joint
*/
public Body getBody1() {
return body1;
}
/**
* Get the second body attached to this joint
*
* @return The second body attached to this joint
*/
public Body getBody2() {
return body2;
}
/**
* Reconfigure this joint
*
* @param b1 The first body attached to this joint
* @param b2 The second body attached to this joint
*/
public void set(Body b1, Body b2) {
body1 = b1;
body2 = b2;
joint1 = new BasicJoint(b1,b2,new Vector2f(b1.getPosition()));
joint2 = new BasicJoint(b2,b1,new Vector2f(b2.getPosition()));
}
/**
* Precaculate everything and apply initial impulse before the
* simulation step takes place
*
* @param invDT The amount of time the simulation is being stepped by
*/
public void preStep(float invDT) {
joint1.preStep(invDT);
joint2.preStep(invDT);
}
/**
* Apply the impulse caused by the joint to the bodies attached.
*/
public void applyImpulse() {
joint1.applyImpulse();
joint2.applyImpulse();
}
/**
* @see java.lang.Object#hashCode()
*/
public int hashCode() {
return id;
}
/**
* @see java.lang.Object#equals(java.lang.Object)
*/
public boolean equals(Object other) {
if (other.getClass() == getClass()) {
return ((FixedJoint) other).id == id;
}
return false;
}
}