com.jme3.bullet.joints.PhysicsJoint Maven / Gradle / Ivy
Show all versions of Minie Show documentation
/*
* Copyright (c) 2009-2018 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
* 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 com.jme3.bullet.joints;
import com.jme3.bullet.NativePhysicsObject;
import com.jme3.bullet.PhysicsSpace;
import com.jme3.bullet.objects.PhysicsBody;
import com.jme3.export.InputCapsule;
import com.jme3.export.JmeExporter;
import com.jme3.export.JmeImporter;
import com.jme3.export.OutputCapsule;
import com.jme3.export.Savable;
import com.jme3.util.clone.Cloner;
import com.jme3.util.clone.JmeCloneable;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import jme3utilities.Validate;
/**
* The abstract base class for physics joints based on Bullet's
* btTypedConstraint, btSoftBody::Anchor, or btSoftBody::Joint.
*
* @author normenhansen
*/
abstract public class PhysicsJoint
extends NativePhysicsObject
implements JmeCloneable, Savable {
// *************************************************************************
// constants and loggers
/**
* message logger for this class
*/
final public static Logger logger
= Logger.getLogger(PhysicsJoint.class.getName());
/**
* field names for serialization
*/
final private static String tagNodeA = "nodeA";
final private static String tagNodeB = "nodeB";
// *************************************************************************
// fields
/**
* body A specified in the constructor, or null for a single-ended joint
* with body B only
*/
private PhysicsBody bodyA = null;
/**
* body B specified in the constructor, or null for a single-ended joint
* with body A only
*/
private PhysicsBody bodyB = null;
/**
* space where this joint is added, or null if none
*/
private PhysicsSpace space = null;
// *************************************************************************
// constructors
/**
* Instantiate a PhysicsJoint.
*
* This no-arg constructor was made explicit to avoid javadoc warnings from
* JDK 18+.
*/
protected PhysicsJoint() {
}
// *************************************************************************
// new methods exposed
/**
* Count how many ends this joint has.
*
* @return 1 if single-ended, 2 if double-ended
*/
public int countEnds() {
if (bodyA == null || bodyB == null) {
return 1;
} else {
return 2;
}
}
/**
* Remove this joint from the joint lists of both ends.
*/
public void destroy() {
if (bodyA != null) {
bodyA.removeJoint(this);
///bodyA = null;
}
if (bodyB != null) {
bodyB.removeJoint(this);
///bodyB = null;
}
}
/**
* Test whether the specified body is an end of this joint.
*
* @param body the body to find (not null, unaffected)
* @return the enum value if found, otherwise null
*/
public JointEnd findEnd(PhysicsBody body) {
Validate.nonNull(body, "body");
if (body == bodyA) {
return JointEnd.A;
} else if (body == bodyB) {
return JointEnd.B;
} else {
return null;
}
}
/**
* Access the remaining body of this joint.
*
* @param body (not null, unaffected)
* @return the body at the other end (null if not found or the joint is
* single-ended)
*/
public PhysicsBody findOtherBody(PhysicsBody body) {
Validate.nonNull(body, "body");
assert bodyA != bodyB;
if (body == bodyA) {
return bodyB;
} else if (body == bodyB) {
return bodyA;
} else {
return null;
}
}
/**
* Access the body at the specified end of this joint.
*
* @param end which end of the joint to access (not null)
* @return the pre-existing body, or null if none
*/
public PhysicsBody getBody(JointEnd end) {
Validate.nonNull(end, "end");
switch (end) {
case A:
return bodyA;
case B:
return bodyB;
default:
throw new IllegalArgumentException("end = " + end);
}
}
/**
* Access the body at the joint's "A" end.
*
* @return the pre-existing body, or null if none
*/
public PhysicsBody getBodyA() {
return bodyA;
}
/**
* Access the body at the joint's "B" end.
*
* @return the pre-existing body, or null if none
*/
public PhysicsBody getBodyB() {
return bodyB;
}
/**
* Access the PhysicsSpace where this joint is added.
*
* @return the pre-existing instance, or null if none
*/
public PhysicsSpace getPhysicsSpace() {
PhysicsSpace result = space;
return result;
}
/**
* Test whether this joint is enabled.
*
* @return true if enabled, otherwise false
*/
abstract public boolean isEnabled();
/**
* Alter which PhysicsSpace this joint is added to. Do not invoke directly!
* The field is updated automatically when added/removed.
*
* @param physicsSpace (may be null)
*/
public void setPhysicsSpace(PhysicsSpace physicsSpace) {
this.space = physicsSpace;
}
// *************************************************************************
// new protected methods
/**
* Specify the body at the joint's "A" end.
*
* @param body the desired body (not null, alias created)
*/
final protected void setBodyA(PhysicsBody body) {
assert body != null;
assert bodyA == null : bodyA;
this.bodyA = body;
}
/**
* Specify the body at the joint's "B" end.
*
* @param body the desired body (not null, alias created)
*/
final protected void setBodyB(PhysicsBody body) {
assert body != null;
assert bodyB == null : bodyB;
this.bodyB = body;
}
// *************************************************************************
// JmeCloneable methods
/**
* Callback from {@link com.jme3.util.clone.Cloner} to convert this
* shallow-cloned object into a deep-cloned one, using the specified Cloner
* and original to resolve copied fields.
*
* @param cloner the Cloner that's cloning this joint (not null)
* @param original the instance from which this joint was shallow-cloned
* (not null, unaffected)
*/
@Override
public void cloneFields(Cloner cloner, Object original) {
assert !hasAssignedNativeObject();
PhysicsJoint old = (PhysicsJoint) original;
assert old != this;
assert old.hasAssignedNativeObject();
PhysicsBody oldBodyA = old.bodyA;
this.bodyA = cloner.clone(oldBodyA);
if (bodyA != null && !bodyA.hasAssignedNativeObject()) {
bodyA.cloneFields(cloner, oldBodyA);
}
assert bodyA == null || bodyA.hasAssignedNativeObject() : bodyA;
PhysicsBody oldBodyB = old.bodyB;
this.bodyB = cloner.clone(oldBodyB);
if (bodyB != null && !bodyB.hasAssignedNativeObject()) {
bodyB.cloneFields(cloner, oldBodyB);
}
assert bodyB == null || bodyB.hasAssignedNativeObject() : bodyA;
this.space = null;
/*
* Each subclass must create the btTypedConstraint, btSoftBody::Anchor,
* or btSoftBody::Joint and invoke setNativeId().
*/
}
/**
* Create a shallow clone for the JME cloner.
*
* @return a new instance
*/
@Override
public PhysicsJoint jmeClone() {
try {
PhysicsJoint clone = (PhysicsJoint) clone();
clone.unassignNativeObject();
return clone;
} catch (CloneNotSupportedException exception) {
throw new RuntimeException(exception);
}
}
// *************************************************************************
// Savable methods
/**
* De-serialize this joint from the specified importer, for example when
* loading from a J3O file.
*
* @param importer (not null)
* @throws IOException from the importer
*/
@Override
public void read(JmeImporter importer) throws IOException {
InputCapsule capsule = importer.getCapsule(this);
this.bodyA = (PhysicsBody) capsule.readSavable(tagNodeA, null);
this.bodyB = (PhysicsBody) capsule.readSavable(tagNodeB, null);
/*
* Each subclass must create the btTypedConstraint, btSoftBody::Anchor,
* or btSoftBody::Joint and then read the remaining properties.
*/
}
/**
* Serialize this joint to the specified exporter, for example when saving
* to a J3O file.
*
* @param exporter (not null)
* @throws IOException from the exporter
*/
@Override
public void write(JmeExporter exporter) throws IOException {
OutputCapsule capsule = exporter.getCapsule(this);
capsule.write(bodyA, tagNodeA, null);
capsule.write(bodyB, tagNodeB, null);
// space is never written.
}
// *************************************************************************
// NativePhysicsObject methods
/**
* Initialize the native ID.
*
* @param jointId the native identifier of the btTypedConstraint,
* btSoftBody::Anchor, or btSoftBody::Joint (not zero)
*/
@Override
protected void setNativeId(long jointId) {
super.setNativeId(jointId);
logger.log(Level.FINE, "Created {0}.", this);
}
/**
* Represent this joint as a String.
*
* @return a descriptive string of text (not null, not empty)
*/
@Override
public String toString() {
String result = getClass().getSimpleName();
result = result.replace("Joint", "");
result = result.replace("Physics", "");
result = result.replace("Point", "P");
result = result.replace("Six", "6");
if (hasAssignedNativeObject()) {
long jointId = nativeId();
result += "#" + Long.toHexString(jointId);
} else {
result += "#unassigned";
}
return result;
}
}