BodyTypes.java

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 * Copyright (c) 2013, Daniel Murphy
 * All rights reserved.
 * 
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 * are permitted provided that the following conditions are met:
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/**
 * .created at 1:14:57 AM Jan 14, 2011
 */
package org.jbox2d.testbed.tests;

import org.jbox2d.collision.shapes.EdgeShape;
import org.jbox2d.collision.shapes.PolygonShape;
import org.jbox2d.common.MathUtils;
import org.jbox2d.common.Vec2;
import org.jbox2d.dynamics.Body;
import org.jbox2d.dynamics.BodyDef;
import org.jbox2d.dynamics.BodyType;
import org.jbox2d.dynamics.FixtureDef;
import org.jbox2d.dynamics.joints.PrismaticJointDef;
import org.jbox2d.dynamics.joints.RevoluteJointDef;
import org.jbox2d.testbed.framework.TestbedSettings;
import org.jbox2d.testbed.framework.TestbedTest;

/**
 * @author Daniel Murphy
 */
public class BodyTypes extends TestbedTest {
  private final static long ATTACHMENT_TAG = 19;
  private final static long PLATFORM_TAG = 20;

  Body m_attachment;
  Body m_platform;
  float m_speed;

  @Override
  public Long getTag(Body body) {
    if (body == m_attachment)
      return ATTACHMENT_TAG;
    if (body == m_platform)
      return PLATFORM_TAG;
    return super.getTag(body);
  }

  @Override
  public void processBody(Body body, Long tag) {
    if (tag == ATTACHMENT_TAG) {
      m_attachment = body;
    } else if (tag == PLATFORM_TAG) {
      m_platform = body;
    } else {
      super.processBody(body, tag);
    }
  }
  
  @Override
  public boolean isSaveLoadEnabled() {
    return true;
  }

  @Override
  public void initTest(boolean deserialized) {
    m_speed = 3.0f;

    if (deserialized) {
      return;
    }

    Body ground = null;
    {
      BodyDef bd = new BodyDef();
      ground = getWorld().createBody(bd);

      EdgeShape shape = new EdgeShape();
      shape.set(new Vec2(-20.0f, 0.0f), new Vec2(20.0f, 0.0f));

      FixtureDef fd = new FixtureDef();
      fd.shape = shape;

      ground.createFixture(fd);
    }

    // Define attachment
    {
      BodyDef bd = new BodyDef();
      bd.type = BodyType.DYNAMIC;
      bd.position.set(0.0f, 3.0f);
      m_attachment = getWorld().createBody(bd);

      PolygonShape shape = new PolygonShape();
      shape.setAsBox(0.5f, 2.0f);
      m_attachment.createFixture(shape, 2.0f);
    }

    // Define platform
    {
      BodyDef bd = new BodyDef();
      bd.type = BodyType.DYNAMIC;
      bd.position.set(-4.0f, 5.0f);
      m_platform = getWorld().createBody(bd);

      PolygonShape shape = new PolygonShape();
      shape.setAsBox(0.5f, 4.0f, new Vec2(4.0f, 0.0f), 0.5f * MathUtils.PI);

      FixtureDef fd = new FixtureDef();
      fd.shape = shape;
      fd.friction = 0.6f;
      fd.density = 2.0f;
      m_platform.createFixture(fd);

      RevoluteJointDef rjd = new RevoluteJointDef();
      rjd.initialize(m_attachment, m_platform, new Vec2(0.0f, 5.0f));
      rjd.maxMotorTorque = 50.0f;
      rjd.enableMotor = true;
      getWorld().createJoint(rjd);

      PrismaticJointDef pjd = new PrismaticJointDef();
      pjd.initialize(ground, m_platform, new Vec2(0.0f, 5.0f), new Vec2(1.0f, 0.0f));

      pjd.maxMotorForce = 1000.0f;
      pjd.enableMotor = true;
      pjd.lowerTranslation = -10.0f;
      pjd.upperTranslation = 10.0f;
      pjd.enableLimit = true;

      getWorld().createJoint(pjd);

    }

    // .create a payload
    {
      BodyDef bd = new BodyDef();
      bd.type = BodyType.DYNAMIC;
      bd.position.set(0.0f, 8.0f);
      Body body = getWorld().createBody(bd);

      PolygonShape shape = new PolygonShape();
      shape.setAsBox(0.75f, 0.75f);

      FixtureDef fd = new FixtureDef();
      fd.shape = shape;
      fd.friction = 0.6f;
      fd.density = 2.0f;

      body.createFixture(fd);
    }
  }

  @Override
  public void step(TestbedSettings settings) {
    super.step(settings);

    addTextLine("Keys: (d) dynamic, (s) static, (k) kinematic");
    // Drive the kinematic body.
    if (m_platform.getType() == BodyType.KINEMATIC) {
      Vec2 p = m_platform.getTransform().p;
      Vec2 v = m_platform.getLinearVelocity();

      if ((p.x < -10.0f && v.x < 0.0f) || (p.x > 10.0f && v.x > 0.0f)) {
        v.x = -v.x;
        m_platform.setLinearVelocity(v);
      }
    }
  }

  @Override
  public void keyPressed(char argKeyChar, int argKeyCode) {
    switch (argKeyChar) {
      case 'd':
        m_platform.setType(BodyType.DYNAMIC);
        break;

      case 's':
        m_platform.setType(BodyType.STATIC);
        break;

      case 'k':
        m_platform.setType(BodyType.KINEMATIC);
        m_platform.setLinearVelocity(new Vec2(-m_speed, 0.0f));
        m_platform.setAngularVelocity(0.0f);
        break;
    }
  }

  @Override
  public String getTestName() {
    return "Body Types";
  }

}