Box2dSquareAABBProximity.java

/*******************************************************************************
 * Copyright 2014 davebaol https://github.com/davebaol
 * 
 * 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.
 ******************************************************************************/

 /*
  * The reportFixture() method was modified from the original to check for a null in the input.
  */

 package com.devcharles.piazzapanic.utility.box2d;

 import com.badlogic.gdx.ai.steer.Proximity;
 import com.badlogic.gdx.ai.steer.Steerable;
 import com.badlogic.gdx.math.Vector2;
 import com.badlogic.gdx.physics.box2d.Fixture;
 import com.badlogic.gdx.physics.box2d.QueryCallback;
 import com.badlogic.gdx.physics.box2d.World;
 
 /** A {@code Box2dSquareAABBProximity} is a {@link Proximity} that queries the world for all fixtures that potentially overlap the
  * square AABB built around the circle having the specified detection radius and whose center is the owner position.
  * 
  * @author davebaol */
 public class Box2dSquareAABBProximity implements Proximity<Vector2>, QueryCallback {
 
     protected Steerable<Vector2> owner;
     protected World world;
     protected ProximityCallback<Vector2> behaviorCallback;
     protected float detectionRadius;
 
     private int neighborCount;
 
     private static final AABB aabb = new AABB();
 
     public Box2dSquareAABBProximity (Steerable<Vector2> owner, World world, float detectionRadius) {
         this.owner = owner;
         this.world = world;
         this.detectionRadius = detectionRadius;
         this.behaviorCallback = null;
         this.neighborCount = 0;
     }
 
     @Override
     public Steerable<Vector2> getOwner () {
         return owner;
     }
 
     @Override
     public void setOwner (Steerable<Vector2> owner) {
         this.owner = owner;
     }
 
     /** Returns the box2d world. */
     public World getWorld () {
         return world;
     }
 
     /** Sets the box2d world. */
     public void setWorld (World world) {
         this.world = world;
     }
 
     /** Returns the detection radius that is half the side of the square AABB. */
     public float getDetectionRadius () {
         return detectionRadius;
     }
 
     /** Sets the detection radius that is half the side of the square AABB. */
     public void setDetectionRadius (float detectionRadius) {
         this.detectionRadius = detectionRadius;
     }
 
     @Override
     public int findNeighbors (ProximityCallback<Vector2> behaviorCallback) {
         this.behaviorCallback = behaviorCallback;
         neighborCount = 0;
         prepareAABB(aabb);
         world.QueryAABB(this, aabb.lowerX, aabb.lowerY, aabb.upperX, aabb.upperY);
         this.behaviorCallback = null;
         return neighborCount;
     }
 
     protected void prepareAABB (AABB aabb) {
         Vector2 position = owner.getPosition();
         aabb.lowerX = position.x - detectionRadius;
         aabb.lowerY = position.y - detectionRadius;
         aabb.upperX = position.x + detectionRadius;
         aabb.upperY = position.y + detectionRadius;
     }
 
     @SuppressWarnings("unchecked")
     protected Steerable<Vector2> getSteerable (Fixture fixture) {
         return (Steerable<Vector2>)fixture.getBody().getUserData();
     }
 
     protected boolean accept (Steerable<Vector2> steerable) {
         return true;
     }
 
     @Override
     public boolean reportFixture (Fixture fixture) {
         Steerable<Vector2> steerable = getSteerable(fixture);
         if (steerable == null) {
            return false;
         }
         if (steerable != owner && accept(steerable)) {
             if (behaviorCallback.reportNeighbor(steerable)) neighborCount++;
         }
         return true;
     }
 
     public static class AABB {
         float lowerX;
         float lowerY;
         float upperX;
         float upperY;
     }
 }