/*******************************************************************************
 * 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;

public interface ContactListener {
	/** Called when two fixtures begin to touch. */
	public void beginContact (Contact contact);

	/** Called when two fixtures cease to touch. */
	public void endContact (Contact contact);

	/*
	 * This is called after a contact is updated. This allows you to inspect a contact before it goes to the solver. If you are
	 * careful, you can modify the contact manifold (e.g. disable contact). A copy of the old manifold is provided so that you can
	 * detect changes. Note: this is called only for awake bodies. Note: this is called even when the number of contact points is
	 * zero. Note: this is not called for sensors. Note: if you set the number of contact points to zero, you will not get an
	 * EndContact callback. However, you may get a BeginContact callback the next step.
	 */
	public void preSolve (Contact contact, Manifold oldManifold);

	/*
	 * This lets you inspect a contact after the solver is finished. This is useful for inspecting impulses. Note: the contact
	 * manifold does not include time of impact impulses, which can be arbitrarily large if the sub-step is small. Hence the
	 * impulse is provided explicitly in a separate data structure. Note: this is only called for contacts that are touching,
	 * solid, and awake.
	 */
	public void postSolve (Contact contact, ContactImpulse impulse);
}