WheelJoint.java

/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package com.badlogic.gdx.physics.box2d.joints;

import com.badlogic.gdx.physics.box2d.Joint;
import com.badlogic.gdx.physics.box2d.World;

/** A wheel joint. This joint provides two degrees of freedom: translation along an axis fixed in body1 and rotation in the plane.
 * You can use a joint limit to restrict the range of motion and a joint motor to drive the rotation or to model rotational
 * friction. This joint is designed for vehicle suspensions. */
public class WheelJoint extends Joint {
	// @off
	/*JNI
#include <Box2D/Box2D.h> 
	 */
	
	public WheelJoint (World world, long addr) {
		super(world, addr);
	}

	/** Get the current joint translation, usually in meters. */
	public float getJointTranslation () {
		return jniGetJointTranslation(addr);
	}

	private native float jniGetJointTranslation (long addr); /*
	  	b2WheelJoint* joint = (b2WheelJoint*)addr;
		return joint->GetJointTranslation();
	*/

	/** Get the current joint translation speed, usually in meters per second. */
	public float getJointSpeed () {
		return jniGetJointSpeed(addr);
	}

	private native float jniGetJointSpeed (long addr); /*
	  	b2WheelJoint* joint = (b2WheelJoint*)addr;
		return joint->GetJointSpeed();
	*/

	/** Is the joint motor enabled? */
	private boolean isMotorEnabled () {
		return jniIsMotorEnabled(addr);
	}

	private native boolean jniIsMotorEnabled (long addr); /*
	  	b2WheelJoint* joint = (b2WheelJoint*)addr;
		return joint->IsMotorEnabled();
	*/

	/** Enable/disable the joint motor. */
	public void enableMotor (boolean flag) {
		jniEnableMotor(addr, flag);
	}

	private native void jniEnableMotor (long addr, boolean flag); /*
	  	b2WheelJoint* joint = (b2WheelJoint*)addr;
		joint->EnableMotor(flag);
	*/

	/** Set the motor speed, usually in radians per second. */
	public void setMotorSpeed (float speed) {
		jniSetMotorSpeed(addr, speed);
	}

	private native void jniSetMotorSpeed (long addr, float speed); /*
	  	b2WheelJoint* joint = (b2WheelJoint*)addr;
		joint->SetMotorSpeed(speed);
	*/

	/** Get the motor speed, usually in radians per second. */
	public float getMotorSpeed () {
		return jniGetMotorSpeed(addr);
	}

	private native float jniGetMotorSpeed (long addr); /*
	  	b2WheelJoint* joint = (b2WheelJoint*)addr;
		return joint->GetMotorSpeed();
	*/

	/** Set/Get the maximum motor force, usually in N-m. */
	public void setMaxMotorTorque (float torque) {
		jniSetMaxMotorTorque(addr, torque);
	}

	private native void jniSetMaxMotorTorque (long addr, float torque); /*
	  	b2WheelJoint* joint = (b2WheelJoint*)addr;
		joint->SetMaxMotorTorque(torque);
	*/

	public float getMaxMotorTorque () {
		return jniGetMaxMotorTorque(addr);
	}

	private native float jniGetMaxMotorTorque (long addr); /*
		b2WheelJoint* joint = (b2WheelJoint*)addr;
		return joint->GetMaxMotorTorque();
	*/

	/** Get the current motor torque given the inverse time step, usually in N-m. */
	public float getMotorTorque (float invDt) {
		return jniGetMotorTorque(addr, invDt);
	}

	private native float jniGetMotorTorque (long addr, float invDt); /*
	  	b2WheelJoint* joint = (b2WheelJoint*)addr;
		return joint->GetMotorTorque(invDt);
	*/

	/** Set/Get the spring frequency in hertz. Setting the frequency to zero disables the spring. */
	public void setSpringFrequencyHz (float hz) {
		jniSetSpringFrequencyHz(addr, hz);
	}

	private native void jniSetSpringFrequencyHz (long addr, float hz); /*
		b2WheelJoint* joint = (b2WheelJoint*)addr;
		joint->SetSpringFrequencyHz(hz);
	*/

	public float getSpringFrequencyHz () {
		return jniGetSpringFrequencyHz(addr);
	}

	private native float jniGetSpringFrequencyHz (long addr); /*
		b2WheelJoint* joint = (b2WheelJoint*)addr;
		return joint->GetSpringFrequencyHz();
	*/

	/** Set/Get the spring damping ratio */
	public void setSpringDampingRatio (float ratio) {
		jniSetSpringDampingRatio(addr, ratio);
	}

	private native void jniSetSpringDampingRatio (long addr, float ratio); /*
		b2WheelJoint* joint = (b2WheelJoint*)addr;
		joint->SetSpringDampingRatio(ratio);
	*/

	public float getSpringDampingRatio () {
		return jniGetSpringDampingRatio(addr);
	}

	private native float jniGetSpringDampingRatio (long addr); /*
		b2WheelJoint* joint = (b2WheelJoint*)addr;
		return joint->GetSpringDampingRatio();
	*/
}