jmonkeyengine/jme3-bullet/src/main/java/com/jme3/bullet/joints/ConeJoint.java

/*
 * 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
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 *
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 * * Redistributions in binary form must reproduce the above copyright
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 *   may be used to endorse or promote products derived from this software
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 * 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.Matrix3f;
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 btConeTwistConstraint.
 * <p>
 * <i>From the Bullet manual:</i><br>
 * To create ragdolls, the cone twist constraint is very useful for limbs like
 * the upper arm. It is a special point to point constraint that adds cone and
 * twist axis limits. The x-axis serves as twist axis.
 *
 * @author normenhansen
 */
public class ConeJoint extends PhysicsJoint {

    protected Matrix3f rotA, rotB;
    protected float swingSpan1 = 1e30f;
    protected float swingSpan2 = 1e30f;
    protected float twistSpan = 1e30f;
    protected boolean angularOnly = false;

    /**
     * No-argument constructor needed by SavableClassUtil. Do not invoke
     * directly!
     */
    protected ConeJoint() {
    }

    /**
     * Instantiate a ConeJoint. 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 ConeJoint(PhysicsRigidBody nodeA, PhysicsRigidBody nodeB, Vector3f pivotA, Vector3f pivotB) {
        super(nodeA, nodeB, pivotA, pivotB);
        this.rotA = new Matrix3f();
        this.rotB = new Matrix3f();
        createJoint();
    }

    /**
     * Instantiate a ConeJoint. 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 local translation of the joint connection point in node A
     * (not null, alias created)
     * @param pivotB local translation of the joint connection point in node B
     * (not null, alias created)
     * @param rotA the local orientation of the connection to node A (not null,
     * alias created)
     * @param rotB the local orientation of the connection to node B (not null,
     * alias created)
     */
    public ConeJoint(PhysicsRigidBody nodeA, PhysicsRigidBody nodeB, Vector3f pivotA, Vector3f pivotB, Matrix3f rotA, Matrix3f rotB) {
        super(nodeA, nodeB, pivotA, pivotB);
        this.rotA = rotA;
        this.rotB = rotB;
        createJoint();
    }

    /**
     * Alter the angular limits for this joint.
     *
     * @param swingSpan1 angle (in radians)
     * @param swingSpan2 angle (in radians)
     * @param twistSpan angle (in radians)
     */
    public void setLimit(float swingSpan1, float swingSpan2, float twistSpan) {
        this.swingSpan1 = swingSpan1;
        this.swingSpan2 = swingSpan2;
        this.twistSpan = twistSpan;
        setLimit(objectId, swingSpan1, swingSpan2, twistSpan);
    }

    private native void setLimit(long objectId, float swingSpan1, float swingSpan2, float twistSpan);

    /**
     * Alter whether this joint is angular only.
     *
     * @param value the desired setting (default=false)
     */
    public void setAngularOnly(boolean value) {
        angularOnly = value;
        setAngularOnly(objectId, value);
    }

    private native void setAngularOnly(long objectId, boolean value);

    /**
     * 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 capsule = ex.getCapsule(this);
        capsule.write(rotA, "rotA", new Matrix3f());
        capsule.write(rotB, "rotB", new Matrix3f());

        capsule.write(angularOnly, "angularOnly", false);
        capsule.write(swingSpan1, "swingSpan1", 1e30f);
        capsule.write(swingSpan2, "swingSpan2", 1e30f);
        capsule.write(twistSpan, "twistSpan", 1e30f);
    }

    /**
     * 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);
        InputCapsule capsule = im.getCapsule(this);
        this.rotA = (Matrix3f) capsule.readSavable("rotA", new Matrix3f());
        this.rotB = (Matrix3f) capsule.readSavable("rotB", new Matrix3f());

        this.angularOnly = capsule.readBoolean("angularOnly", false);
        this.swingSpan1 = capsule.readFloat("swingSpan1", 1e30f);
        this.swingSpan2 = capsule.readFloat("swingSpan2", 1e30f);
        this.twistSpan = capsule.readFloat("twistSpan", 1e30f);
        createJoint();
    }

    /**
     * Create the configured joint in Bullet.
     */
    protected void createJoint() {
        objectId = createJoint(nodeA.getObjectId(), nodeB.getObjectId(), pivotA, rotA, pivotB, rotB);
        Logger.getLogger(this.getClass().getName()).log(Level.FINE, "Created Joint {0}", Long.toHexString(objectId));
        setLimit(objectId, swingSpan1, swingSpan2, twistSpan);
        setAngularOnly(objectId, angularOnly);
    }

    private native long createJoint(long objectIdA, long objectIdB, Vector3f pivotA, Matrix3f rotA, Vector3f pivotB, Matrix3f rotB);
}