com.jme3.bullet.joints.Point2PointJoint Maven / Gradle / Ivy
/*
* Copyright (c) 2009-2019 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
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*
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* 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
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package com.jme3.bullet.joints;
import com.jme3.bullet.objects.PhysicsRigidBody;
import com.jme3.export.InputCapsule;
import com.jme3.export.JmeExporter;
import com.jme3.export.JmeImporter;
import com.jme3.export.OutputCapsule;
import com.jme3.math.Vector3f;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* A joint based on Bullet's btPoint2PointConstraint.
*
* From the Bullet manual:
* Point to point constraint limits the translation so that the local pivot
* points of 2 rigidbodies match in worldspace. A chain of rigidbodies can be
* connected using this constraint.
*
* @author normenhansen
*/
public class Point2PointJoint extends PhysicsJoint {
/**
* No-argument constructor needed by SavableClassUtil. Do not invoke
* directly!
*/
protected Point2PointJoint() {
}
/**
* Instantiate a Point2PointJoint. To be effective, the joint must be added
* to a physics space.
*
* @param nodeA the 1st body connected by the joint (not null, alias
* created)
* @param nodeB the 2nd body connected by the joint (not null, alias
* created)
* @param pivotA the local offset of the connection point in node A (not
* null, alias created)
* @param pivotB the local offset of the connection point in node B (not
* null, alias created)
*/
public Point2PointJoint(PhysicsRigidBody nodeA, PhysicsRigidBody nodeB, Vector3f pivotA, Vector3f pivotB) {
super(nodeA, nodeB, pivotA, pivotB);
createJoint();
}
/**
* Alter the joint's damping.
*
* @param value the desired viscous damping ratio (0→no damping,
* 1→critically damped, default=1)
*/
public void setDamping(float value) {
setDamping(objectId, value);
}
private native void setDamping(long objectId, float value);
/**
* Alter the joint's impulse clamp.
*
* @param value the desired impulse clamp value (default=0)
*/
public void setImpulseClamp(float value) {
setImpulseClamp(objectId, value);
}
private native void setImpulseClamp(long objectId, float value);
/**
* Alter the joint's tau value.
*
* @param value the desired tau value (default=0.3)
*/
public void setTau(float value) {
setTau(objectId, value);
}
private native void setTau(long objectId, float value);
/**
* Read the joint's damping ratio.
*
* @return the viscous damping ratio (0→no damping, 1→critically
* damped)
*/
public float getDamping() {
return getDamping(objectId);
}
private native float getDamping(long objectId);
/**
* Read the joint's impulse clamp.
*
* @return the clamp value
*/
public float getImpulseClamp() {
return getImpulseClamp(objectId);
}
private native float getImpulseClamp(long objectId);
/**
* Read the joint's tau value.
*
* @return the tau value
*/
public float getTau() {
return getTau(objectId);
}
private native float getTau(long objectId);
/**
* Serialize this joint, for example when saving to a J3O file.
*
* @param ex exporter (not null)
* @throws IOException from exporter
*/
@Override
public void write(JmeExporter ex) throws IOException {
super.write(ex);
OutputCapsule cap = ex.getCapsule(this);
cap.write(getDamping(), "damping", 1.0f);
cap.write(getTau(), "tau", 0.3f);
cap.write(getImpulseClamp(), "impulseClamp", 0f);
}
/**
* De-serialize this joint, for example when loading from a J3O file.
*
* @param im importer (not null)
* @throws IOException from importer
*/
@Override
public void read(JmeImporter im) throws IOException {
super.read(im);
createJoint();
InputCapsule cap = im.getCapsule(this);
setDamping(cap.readFloat("damping", 1.0f));
setDamping(cap.readFloat("tau", 0.3f));
setDamping(cap.readFloat("impulseClamp", 0f));
}
/**
* Create the configured joint in Bullet.
*/
protected void createJoint() {
objectId = createJoint(nodeA.getObjectId(), nodeB.getObjectId(), pivotA, pivotB);
Logger.getLogger(this.getClass().getName()).log(Level.FINE, "Created Joint {0}", Long.toHexString(objectId));
}
private native long createJoint(long objectIdA, long objectIdB, Vector3f pivotA, Vector3f pivotB);
}