Android Open Source - Avoidance Utils

• Back to Game/ball  ↑

From Project

Back to project page Avoidance.

License

The source code is released under:

GNU General Public License

Java Source Code

/* 
 * Copyright (c) 2012 Florian Minges, Filip Brynfors
 * /*from w w w. j av  a  2 s  . com*/
 * This file is part of Avoidance.
 * 
 * Avoidance is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Avoidance is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Avoidance.  If not, see <http://www.gnu.org/licenses/>. 
 *  
 */

package se.chalmers.avoidance.util;

import java.util.List;

/**
 * Contains a set of static helper-methods.
 * 
 * @author Florian Minges, Filip Brynfors
 * 
 */
public final class Utils {

  private Utils() {
  }

  /**
   * Simplifies the angle so that it fits in the interval 0 <= angle < (2 *
   * PI).
   * 
   * @param angle
   *            The angle you want to simplify.
   * @return The simplified angle.
   */
  public static float simplifyAngle(float angle) {
    float simplifiedAngle = angle % (float) (2 * Math.PI);
    return simplifiedAngle < 0 ? (simplifiedAngle + (float) (2 * Math.PI))
        : simplifiedAngle; // make angle positive
  }

  /**
   * Calculates the speed of the horizontal part of the velocity with the
   * given angle and speed.
   * 
   * @param speed
   *            the speed of the velocity
   * @param angle
   *            the angle of the velocity
   * @return the horizontal part of the velocity
   */
  public static float getHorizontalSpeed(float speed, float angle) {
    return (float) (speed * Math.cos(angle));
  }

  /**
   * Calculates the speed of the vertical part of the velocity with the given
   * angle and speed.
   * 
   * @param speed
   *            the speed of the velocity
   * @param angle
   *            the angle of the velocity
   * @return the vertical part of the velocity
   */
  public static float getVerticalSpeed(float speed, float angle) {
    return (float) (speed * Math.sin(angle));
  }

  /**
   * Returns an angle that points in the opposite direction. This is equal to
   * adding/subracting 180 degrees, or PI radians. If you are looking for a
   * way to simplify your angle, see {@link #simplifyAngle(float)
   * simplifyAngle(float)}.
   * 
   * @param angle
   *            the angle to reverse
   * @return the reversed angle.
   */
  public static float reverseAngle(float angle) {
    float rotation = (angle < (float) Math.PI) ? 1f : -1f;
    return angle + (float) Math.PI * rotation;
  }

  /**
   * Trims the list size of the supplied <code>List</code> to contain a
   * maximum of <code>maxElements</code> elements, as specified by the
   * argument.
   * <p>
   * 
   * If <code>maxElements</code> is larger than the lists size, then the last
   * elements in the list are removed.
   * 
   * @param list
   *            the list to trim
   * @param maxElements
   *            the maximum number of allowed elements in the list
   */
  public static void trimList(List<?> list, int maxElements) {
    int size = list.size();
    int diff = size - maxElements;
    for (int i = 1; i <= diff; i++) {
      list.remove(size - i);
    }
  }

}

Java Source Code List

• Back to Game/ball  ↑