ConvexHull.java

/*******************************************************************************
 * Copyright (c) 2013, 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.
 * 
 * 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 THE COPYRIGHT HOLDER OR CONTRIBUTORS 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.
 ******************************************************************************/
package org.jbox2d.testbed.tests;

import org.jbox2d.collision.shapes.PolygonShape;
import org.jbox2d.common.Color3f;
import org.jbox2d.common.MathUtils;
import org.jbox2d.common.Settings;
import org.jbox2d.common.Vec2;
import org.jbox2d.testbed.framework.TestbedSettings;
import org.jbox2d.testbed.framework.TestbedTest;

public class ConvexHull extends TestbedTest {

  private final int e_count = Settings.maxPolygonVertices;

  private boolean m_auto = false;
  private Vec2[] m_points = new Vec2[Settings.maxPolygonVertices];
  private int m_count;

  @Override
  public void initTest(boolean deserialized) {
    if (deserialized) {
      return;
    }
    generate();
  }

  void generate() {
    Vec2 lowerBound = new Vec2(-8f, -8f);
    Vec2 upperBound = new Vec2(8f, 8f);

    for (int i = 0; i < e_count; i++) {
      float x = MathUtils.randomFloat(-8, 8);
      float y = MathUtils.randomFloat(-8, 8);

      Vec2 v = new Vec2(x, y);
      MathUtils.clampToOut(v, lowerBound, upperBound, v);
      m_points[i] = v;
    }
    m_count = e_count;
  }

  public void keyPressed(char argKeyChar, int argKeyCode) {
    if (argKeyChar == 'g') {
      generate();
    } else if (argKeyChar == 'a') {
      m_auto = !m_auto;
    }
  }

  PolygonShape shape = new PolygonShape();
  Color3f color = new Color3f(.9f, .9f, .9f);
  Color3f color2 = new Color3f(.9f, .5f, .5f);

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

    shape.set(m_points, m_count);

    addTextLine("Press g to generate a new random convex hull");

    getDebugDraw().drawPolygon(shape.m_vertices, shape.m_count, color);

    for (int i = 0; i < m_count; ++i) {
      getDebugDraw().drawPoint(m_points[i], 2.0f, color2);
      getDebugDraw().drawString(m_points[i].add(new Vec2(0.05f, 0.05f)), i + "", Color3f.WHITE);
    }

    assert (shape.validate());


    if (m_auto) {
      generate();
    }
  }

  @Override
  public String getTestName() {
    return "Convex Hull";
  }

}