ContactImpulse.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;

/**
 * Contact impulses for reporting. Impulses are used instead of forces because sub-step forces may approach infinity for
 * rigid body collisions. These match up one-to-one with the contact points in b2Manifold.
 * 
 * @author mzechner
 */
public class ContactImpulse {
	// @off
	/*JNI
	#include <Box2D/Box2D.h>
	 */

	final World world;
	long addr;
	float[] tmp = new float[2];
	final float[] normalImpulses = new float[2];
	final float[] tangentImpulses = new float[2];

	protected ContactImpulse(World world, long addr) {
		this.world = world;
		this.addr = addr;
	}

	public float[] getNormalImpulses() {
		jniGetNormalImpulses(addr, normalImpulses);
		return normalImpulses;
	}

	private native void jniGetNormalImpulses(long addr, float[] values); /*
																			b2ContactImpulse* contactImpulse = (b2ContactImpulse*)addr;	
																			values[0] = contactImpulse->normalImpulses[0];
																			values[1] = contactImpulse->normalImpulses[1];
																			*/

	public float[] getTangentImpulses() {
		jniGetTangentImpulses(addr, tangentImpulses);
		return tangentImpulses;
	}

	private native void jniGetTangentImpulses(long addr, float[] values); /*
																			b2ContactImpulse* contactImpulse = (b2ContactImpulse*)addr;	
																			values[0] = contactImpulse->tangentImpulses[0];
																			values[1] = contactImpulse->tangentImpulses[1];
																			*/

	public int getCount() {
		return jniGetCount(addr);
	}

	private native int jniGetCount(long addr); /*
												b2ContactImpulse* contactImpulse = (b2ContactImpulse*)addr;
												return contactImpulse->count;
												*/
}