Gears.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 4:25:03 AM Jan 15, 2011
 */
package org.jbox2d.gwt.showcase.client.example;

import org.jbox2d.collision.shapes.CircleShape;
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.GearJoint;
import org.jbox2d.dynamics.joints.GearJointDef;
import org.jbox2d.dynamics.joints.PrismaticJoint;
import org.jbox2d.dynamics.joints.PrismaticJointDef;
import org.jbox2d.dynamics.joints.RevoluteJoint;
import org.jbox2d.dynamics.joints.RevoluteJointDef;
import org.jbox2d.gwt.showcase.client.framework.BaseExample;
import org.jbox2d.gwt.showcase.client.framework.ShowcaseSettings;

/**
 * @author Daniel Murphy
 */
public class Gears extends BaseExample {
	
	RevoluteJoint m_joint1;
	RevoluteJoint m_joint2;
	PrismaticJoint m_joint3;
	GearJoint m_joint4;
	GearJoint m_joint5;
	
	/**
	 * @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(50.0f, 0.0f), new Vec2(-50.0f, 0.0f));
			ground.createFixture(shape, 0.0f);
		}

		{
			CircleShape circle1 = new CircleShape();
			circle1.m_radius = 1.0f;

			CircleShape circle2 = new CircleShape();
			circle2.m_radius = 2.0f;
			
			PolygonShape box = new PolygonShape();
			box.setAsBox(0.5f, 5.0f);

			BodyDef bd1 = new BodyDef();
			bd1.type = BodyType.DYNAMIC;
			bd1.position.set(-3.0f, 12.0f);
			Body body1 = m_world.createBody(bd1);
			body1.createFixture(circle1, 5.0f);

			RevoluteJointDef jd1 = new RevoluteJointDef();
			jd1.bodyA = ground;
			jd1.bodyB = body1;
			jd1.localAnchorA = ground.getLocalPoint(bd1.position);
			jd1.localAnchorB = body1.getLocalPoint(bd1.position);
			jd1.referenceAngle = body1.getAngle() - ground.getAngle();
			m_joint1 = (RevoluteJoint)m_world.createJoint(jd1);

			BodyDef bd2 = new BodyDef();
			bd2.type = BodyType.DYNAMIC;
			bd2.position.set(0.0f, 12.0f);
			Body body2 = m_world.createBody(bd2);
			body2.createFixture(circle2, 5.0f);

			RevoluteJointDef jd2 = new RevoluteJointDef();
			jd2.initialize(ground, body2, bd2.position);
			m_joint2 = (RevoluteJoint)m_world.createJoint(jd2);

			BodyDef bd3 = new BodyDef();
			bd3.type = BodyType.DYNAMIC;
			bd3.position.set(2.5f, 12.0f);
			Body body3 = m_world.createBody(bd3);
			body3.createFixture(box, 5.0f);

			PrismaticJointDef jd3 = new PrismaticJointDef();
			jd3.initialize(ground, body3, bd3.position, new Vec2(0.0f, 1.0f));
			jd3.lowerTranslation = -5.0f;
			jd3.upperTranslation = 5.0f;
			jd3.enableLimit = true;

			m_joint3 = (PrismaticJoint)m_world.createJoint(jd3);

			GearJointDef jd4 = new GearJointDef();
			jd4.bodyA = body1;
			jd4.bodyB = body2;
			jd4.joint1 = m_joint1;
			jd4.joint2 = m_joint2;
			jd4.ratio = circle2.m_radius / circle1.m_radius;
			m_joint4 = (GearJoint)m_world.createJoint(jd4);

			GearJointDef jd5 = new GearJointDef();
			jd5.bodyA = body2;
			jd5.bodyB = body3;
			jd5.joint1 = m_joint2;
			jd5.joint2 = m_joint3;
			jd5.ratio = -1.0f / circle2.m_radius;
			m_joint5 = (GearJoint)m_world.createJoint(jd5);
		}
	}
	
	/**
	 * @see org.jbox2d.testbed.framework.TestbedTest#step(org.jbox2d.testbed.framework.ShowcaseSettings)
	 */
	@Override
	public void render(ShowcaseSettings settings) {
		super.render(settings);
		
		float ratio, value;
		
		ratio = m_joint4.getRatio();
		value = m_joint1.getJointAngle() + ratio * m_joint2.getJointAngle();
		
		addTextLine("theta1 + "+ratio+" * theta2 = "+value);

		ratio = m_joint5.getRatio();
		value = m_joint2.getJointAngle() + ratio * m_joint3.getJointTranslation();
		addTextLine("theta2 + "+ratio+" * delta = "+value);
	}
	
	/**
	 * @see org.jbox2d.testbed.framework.TestbedTest#getTestName()
	 */
	@Override
	public String getTestName() {
		return "Gears";
	}
}