Pulleys.java

/*******************************************************************************
 * Copyright (c) 2011, Daniel Murphy
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the <organization> nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL DANIEL MURPHY BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ******************************************************************************/
/**
 * Created at 12:46:04 PM Jan 23, 2011
 */
package org.jbox2d.gwt.showcase.client.example;

import org.jbox2d.collision.shapes.PolygonShape;
import org.jbox2d.common.Vec2;
import org.jbox2d.dynamics.Body;
import org.jbox2d.dynamics.BodyDef;
import org.jbox2d.dynamics.BodyType;
import org.jbox2d.dynamics.joints.PulleyJoint;
import org.jbox2d.dynamics.joints.PulleyJointDef;
import org.jbox2d.gwt.showcase.client.framework.BaseExample;
import org.jbox2d.gwt.showcase.client.framework.ShowcaseSettings;

/**
 * @author Daniel Murphy
 */
public class Pulleys extends BaseExample {
	
	PulleyJoint m_joint1;
	/**
	 * @see org.jbox2d.testbed.framework.TestbedTest#initTest()
	 */
	@Override
	public void initTest() {
		Body ground = null;
		{
			BodyDef bd = new BodyDef();
			ground = m_world.createBody(bd);

			PolygonShape shape = new PolygonShape();
			shape.setAsEdge(new Vec2(-40.0f, 0.0f), new Vec2(40.0f, 0.0f));
			ground.createFixture(shape, 0.0f);
		}

		{
			float a = 2.0f;
			float b = 4.0f;
			float y = 16.0f;
			float L = 12.0f;

			PolygonShape shape = new PolygonShape();
			shape.setAsBox(a, b);

			BodyDef bd = new BodyDef();
			bd.type = BodyType.DYNAMIC;

			bd.position.set(-10.0f, y);
			Body body1 = m_world.createBody(bd);
			body1.createFixture(shape, 5.0f);

			bd.position.set(10.0f, y);
			Body body2 = m_world.createBody(bd);
			body2.createFixture(shape, 5.0f);

			PulleyJointDef pulleyDef = new PulleyJointDef();
			Vec2 anchor1 = new Vec2(-10.0f, y + b);
			Vec2 anchor2 = new Vec2(10.0f, y + b);
			Vec2 groundAnchor1 = new Vec2(-10.0f, y + b + L);
			Vec2 groundAnchor2 = new Vec2(10.0f, y + b + L);
			pulleyDef.initialize(body1, body2, groundAnchor1, groundAnchor2, anchor1, anchor2, 2.0f);

			m_joint1 = (PulleyJoint)m_world.createJoint(pulleyDef);
		}
	}
	
	@Override
	public void render(ShowcaseSettings settings) {
		super.render(settings);
		float ratio = m_joint1.getRatio();
		float L = m_joint1.getLength1() + ratio * m_joint1.getLength2();
		addTextLine("L1 + "+ratio+" * L2 = "+L);
		if(L >= 36){
			addTextLine("Pulley is taught");
		}
	}
	/**
	 * @see org.jbox2d.testbed.framework.TestbedTest#getTestName()
	 */
	@Override
	public String getTestName() {
		return "Pulleys";
	}
	
}