com.jme3.bullet.joints

Class SoftPhysicsJoint

java.lang.Object

com.jme3.bullet.NativePhysicsObject

com.jme3.bullet.joints.PhysicsJoint

com.jme3.bullet.joints.SoftPhysicsJoint

All Implemented Interfaces:

java.lang.Comparable<NativePhysicsObject>

Direct Known Subclasses:

SoftAngularJoint, SoftLinearJoint

public abstract class SoftPhysicsJoint
extends PhysicsJoint

The abstract base class for joining a PhysicsSoftBody to another body, based on Bullet's btSoftBody::Joint. A SoftPhysicsJoint can be soft-soft or soft-rigid:

• a soft-soft joint joins particular clusters of 2 distinct soft bodies
• a soft-rigid joint joins a particular cluster of a soft body to a rigid body

Subclasses include SoftLinearJoint and SoftAngularJoint.

To join a particular *node* of a soft body to a rigid body, use an Anchor instead.

Field Summary

Fields

Modifier and Type	Field and Description
static java.util.logging.Logger	logger2 message logger for this class

Fields inherited from class com.jme3.bullet.joints.PhysicsJoint

logger

Fields inherited from class com.jme3.bullet.NativePhysicsObject

loggerN

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	SoftPhysicsJoint(PhysicsSoftBody softBodyA, int clusterIndexA, PhysicsRigidBody rigidBodyB) Instantiate a SoftPhysicsJoint to join a soft-body cluster and a rigid body.
protected	SoftPhysicsJoint(PhysicsSoftBody softBodyA, int clusterIndexA, PhysicsSoftBody softBodyB, int clusterIndexB) Instantiate a SoftPhysicsJoint to join 2 soft bodies.

Method Summary

Modifier and Type	Method and Description
boolean	checkParameters() Compare Bullet parameters against their local copies.
int	clusterIndexA() Read the index of the cluster for the A end.
int	clusterIndexB() Read the index of the cluster for the B end.
protected static void	finalizeNative(long jointId) Finalize the btTypedConstraint.
float	getCFM() Read the constraint force mixing coefficient (aka CFM).
float	getERP() Read the error-reduction parameter (aka ERP).
PhysicsSoftBody	getSoftBodyA() Access the soft body at the A end.
PhysicsSoftBody	getSoftBodyB() Access the soft body at the B end.
float	getSplit() Return the split.
boolean	isEnabled() Test whether this joint is enabled.
boolean	isSoftRigid() Test whether this joint is a soft-rigid joint.
boolean	isSoftSoft() Test whether this joint is a soft-soft joint.
void	setCFM(float cfm) Set the constraint force mixing coefficient (aka CFM).
void	setERP(float erp) Set the error-reduction parameter (aka ERP).
void	setSplit(float split) Alter the split.

Methods inherited from class com.jme3.bullet.joints.PhysicsJoint

countEnds, destroy, findEnd, findOtherBody, getBody, getBodyA, getBodyB, getPhysicsSpace, setBodyA, setBodyB, setNativeId, setPhysicsSpace, toString

Methods inherited from class com.jme3.bullet.NativePhysicsObject

compareTo, countTrackers, dumpTrackers, equals, freeUnusedObjects, hasAssignedNativeObject, hashCode, nativeId, reassignNativeId, setNativeIdNotTracked, unassignNativeObject

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

logger2

public static final java.util.logging.Logger logger2

message logger for this class

Constructor Detail

SoftPhysicsJoint

protected SoftPhysicsJoint(PhysicsSoftBody softBodyA,
                           int clusterIndexA,
                           PhysicsRigidBody rigidBodyB)

Instantiate a SoftPhysicsJoint to join a soft-body cluster and a rigid body.

To be fully effective, the joint must be added to the PhysicsSoftSpace of both bodies.

Parameters:

softBodyA - the soft body for the A end (not null, alias created)

clusterIndexA - the index of the cluster for the A end (≥0)

rigidBodyB - the rigid body for the B end (not null, alias created)

SoftPhysicsJoint

protected SoftPhysicsJoint(PhysicsSoftBody softBodyA,
                           int clusterIndexA,
                           PhysicsSoftBody softBodyB,
                           int clusterIndexB)

Instantiate a SoftPhysicsJoint to join 2 soft bodies.

To be effective, the joint must be added to the PhysicsSoftSpace of both bodies. Also, the bodies must be distinct.

Parameters:

softBodyA - the body for the A end (not null, alias created)

clusterIndexA - the index of the cluster for the A end (≥0)

softBodyB - the body for the B end (not null, alias created)

clusterIndexB - the index of the cluster for the B end (≥0)

Method Detail

checkParameters

public boolean checkParameters()

Compare Bullet parameters against their local copies.

Returns:

true if the local copies are accurate, otherwise false

clusterIndexA

public int clusterIndexA()

Read the index of the cluster for the A end.

Returns:

the index (≥0)

clusterIndexB

public int clusterIndexB()

Read the index of the cluster for the B end.

Returns:

the index (≥0) or -1 for a soft-rigid joint

getCFM

public float getCFM()

Read the constraint force mixing coefficient (aka CFM).

From the Bullet documentation:

• If CFM=0 then the constraint will be hard.
• If CFM is set to a positive value, it will be possible to violate the constraint by "pushing on it" (for example, for contact constraints by forcing the two contacting objects together). In other words the constraint will be soft, and the softness will increase as CFM increases.

Returns:

the coefficient value (≥0)

getERP

public float getERP()

Read the error-reduction parameter (aka ERP).

From the Bullet documentation:

The ERP specifies what proportion of the joint error will be fixed during the next simulation step.

• If ERP=0 then no correcting force is applied and the bodies will eventually drift apart as the simulation proceeds.
• If ERP=1 then the simulation will attempt to fix all joint error during the next simulation step. However, setting ERP=1 is not recommended, as the joint error will not be completely fixed due to various internal approximations.

Values between 0.1 and 0.8 are recommended.

Returns:

the parameter value (≥0, ≤1, default=1)

getSoftBodyA

public PhysicsSoftBody getSoftBodyA()

Access the soft body at the A end.

Returns:

the pre-existing soft body (not null)

getSoftBodyB

public PhysicsSoftBody getSoftBodyB()

Access the soft body at the B end.

Returns:

the pre-existing soft body, or null for a soft-rigid joint

getSplit

public float getSplit()

Return the split.

Returns:

the split value

isSoftRigid

public boolean isSoftRigid()

Test whether this joint is a soft-rigid joint.

Returns:

true if soft-rigid, otherwise false

isSoftSoft

public boolean isSoftSoft()

Test whether this joint is a soft-soft joint.

Returns:

true if soft-soft, otherwise false

setCFM

public void setCFM(float cfm)

Set the constraint force mixing coefficient (aka CFM).

From the Bullet documentation:

• If CFM=0 then the constraint will be hard.
• If CFM is set to a positive value, it will be possible to violate the constraint by "pushing on it" (for example, for contact constraints by forcing the two contacting objects together). In other words the constraint will be soft, and the softness will increase as CFM increases.

Setting CFM to a negative value can cause instability.

Parameters:

cfm - the desired coefficient value (≥0, default=1)

setERP

public void setERP(float erp)

Set the error-reduction parameter (aka ERP).

From the Bullet documentation:

The ERP specifies what proportion of the joint error will be fixed during the next simulation step.

• If ERP=0 then no correcting force is applied and the bodies will eventually drift apart as the simulation proceeds.
• If ERP=1 then the simulation will attempt to fix all joint error during the next simulation step. However, setting ERP=1 is not recommended, as the joint error will not be completely fixed due to various internal approximations.

Values between 0.1 and 0.8 are recommended.

Parameters:

erp - the desired parameter value (≥0, ≤1, default=1)

setSplit

public void setSplit(float split)

Alter the split.

Parameters:

split - the desired split value (default=1)

finalizeNative

protected static void finalizeNative(long jointId)

Finalize the btTypedConstraint.

Parameters:

jointId - identifier of the btSoftBody::Joint (not zero)

isEnabled

public boolean isEnabled()

Test whether this joint is enabled.

Specified by:

isEnabled in class PhysicsJoint

Returns:

true