BodyUpdateAction.java

/*
 * -----------------------------------------------------------------------
 * Copyright 2012 - Alistair Rutherford - www.netthreads.co.uk
 * -----------------------------------------------------------------------
 * 
 * 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.netthreads.libgdx.action;

import com.badlogic.gdx.math.MathUtils;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.Body;
import com.badlogic.gdx.physics.box2d.World;
import com.badlogic.gdx.scenes.scene2d.Action;
import com.badlogic.gdx.utils.Pool;

/**
 * BodyUpdateAction - Box2D Action
 * 
 * Map Box2D body to view coordinates.
 * 
 * Note: This action 'owns' body and will destroy it when finished. It normally
 * runs all the time against an active body.
 * 
 */
public class BodyUpdateAction extends Action
{
	private static final Pool<BodyUpdateAction> pool = new Pool<BodyUpdateAction>(10, 100)
	{
		@Override
		protected BodyUpdateAction newObject()
		{
			BodyUpdateAction action = new BodyUpdateAction();
			
			action.setPool(this);
			
			return action;
		}
		
		/**
		 * Override the 'free to ensure the object is removed from the 'world'
		 * as well.
		 */
		public void free(BodyUpdateAction object)
		{
			super.free(object);
			
			object.getWorld().destroyBody(object.getBody());
		}
	};
	
	private World world;
	private Body body;
	private float pixelsPerMetre;
	private boolean centred;
	
	/**
	 * Get instance from pool.
	 * 
	 * @param world
	 *            The Box2D world reference.
	 * @param body
	 *            The Box2D body reference.
	 * @param pixelsPerMetre
	 *            The conversion ratio.
	 * @param centred
	 *            If true the actor positioned at centre of body.
	 * 
	 * @return The pooled instance.
	 */
	public static BodyUpdateAction $(World world, Body body, float pixelsPerMetre, boolean centred)
	{
		BodyUpdateAction action = pool.obtain();
		
		action.setWorld(world);
		action.setBody(body);
		action.setPixelsPerMetre(pixelsPerMetre);
		action.setCentre(centred);
		
		return action;
	}
	
	/**
	 * Action.
	 * 
	 */
	@Override
	public boolean act(float delta)
	{
		// Centre body.
		Vector2 pos = body.getPosition();
		
		if (centred)
		{
			// Adjust the actor to centre
			getActor().setX((pos.x * pixelsPerMetre) - getActor().getWidth() / 2);
			getActor().setY((pos.y * pixelsPerMetre) - getActor().getHeight() / 2);
		}
		else
		{
			getActor().setX(pos.x * pixelsPerMetre);
			getActor().setY(pos.y * pixelsPerMetre);
		}
		
		float angleDeg = body.getAngle() * MathUtils.radiansToDegrees;
		
		getActor().setRotation(angleDeg);
		
		return false;
	}
	
	public World getWorld()
	{
		return world;
	}
	
	public void setWorld(World world)
	{
		this.world = world;
	}
	
	/**
	 * Set Body reference.
	 * 
	 * @param body
	 */
	private void setBody(Body body)
	{
		this.body = body;
	}
	
	/**
	 * Fetch Body reference.
	 * 
	 * @return The Body reference.
	 */
	public Body getBody()
	{
		return body;
	}
	
	/**
	 * Return ppm conversion factor.
	 * 
	 * @return
	 */
	public float getPixelsPerMetre()
	{
		return pixelsPerMetre;
	}
	
	/**
	 * Set PPM conversion factor.
	 * 
	 * @param pixelsPerMetre
	 */
	public void setPixelsPerMetre(float pixelsPerMetre)
	{
		this.pixelsPerMetre = pixelsPerMetre;
	}
	
	public boolean isCentre()
	{
		return centred;
	}
	
	public void setCentre(boolean centre)
	{
		this.centred = centre;
	}
	
}