PluggableRobot/Math2

/*
 * PluggableRobot, by Robert J. Walker
 * Home page: http://robowiki.net/cgi-bin/robowiki?PluggableRobot
 * This software is made available under the RoboWiki Public Code License (RWPCL). The full text of
 * the license may be found at http://robowiki.net/cgi-bin/robowiki?RWPCL.
 */
package rjw.pluggablerobot;

import java.awt.geom.Point2D;
import java.util.Random;

import robocode.Rules;
import robocode.util.Utils;

/**
 * Math utility class.
 * @author Robert J. Walker
 */
public final class Math2 {
	public static final double PI_OVER_2 = Math.PI / 2;

	private static final Random random = new Random();

	private Math2() {
	}

	/**
	 * Returns a random int between the min and max arguments, inclusive.
	 */
    public static int randomInteger(int min, int max) {
    	return random.nextInt(max - min + 1) + min;
    }

    /**
     * Returns a random double value between 0.0 (inclusive) and 1.0 (exclusive).
     */
    public static double randomDouble() {
    	return random.nextDouble();
    }

    /**
     * If value is less than min, returns min. If value is greater than max, returns max. Otherwise,
     * returns value.
     */
    public static double limit(double min, double value, double max) {
        return Math.max(min, Math.min(value, max));
    }

    /**
     * Adds the X and Y components of the given Point2D.Double objects and returns a new
     * Point2D.Double object with the result.
     */
    public static Point2D.Double add(Point2D.Double point1, Point2D.Double point2) {
		return new Point2D.Double(point1.x + point2.x, point1.y + point2.y);
	}

    /**
     * Subtracts the X and Y components of the second given Point2D.Double object from those of the
     * first and returns a new Point2D.Double object with the result.
     */
	public static Point2D.Double subtract(Point2D.Double point1, Point2D.Double point2) {
		return new Point2D.Double(point1.x - point2.x, point1.y - point2.y);
	}

	/**
	 * Returns the absolute bearing in radians from the given origin point to the given target
	 * point.
	 */
	public static double getAbsoluteTargetBearing(Point2D.Double origin, Point2D.Double target) {
		return Utils.normalAbsoluteAngle(Math.atan2(target.x - origin.x, target.y - origin.y));
	}

	/**
	 * Returns a Point2D.Double object indicating the relative position of an object at the given
	 * angle and distance from the origin.
	 */
	public static Point2D.Double getRelativePosition(double angle, double distance) {
		double dx = distance * Math.sin(angle);
		double dy = distance * Math.cos(angle);
		return new Point2D.Double(dx, dy);
	}

	/**
	 * Returns a Point2D.Double object indicating the position of an object at the given angle and
	 * distance from the given origin point.
	 */
	public static Point2D.Double getAbsolutePosition(Point2D.Double origin, double angle, double distance) {
		double x = origin.x + distance * Math.sin(angle);
		double y = origin.y + distance * Math.cos(angle);
		return new Point2D.Double(x, y);
	}

    /**
     * Returns the fire power of a bullet that causes the given amount of damage. Useful to prevent
     * firing stronger bullets than you have to.
     * http://robowiki.net/cgi-bin/robowiki?SelectingFirePower
     */
    public static double damageToFirePower(double damage) {
    	return limit(Rules.MIN_BULLET_POWER, damage >= 4 ? (damage + 2) / 6 : damage / 4, Rules.MAX_BULLET_POWER);
    }

    /**
     * Returns the accuracy (hit percentage) required of a gun to make it cost effective for a
     * bullet with the given power. This is the crossover point where the cost of firing the bullet
     * is surpassed by the damage inflicted by it times the odds of a hit.
     */
    public static double minEffectiveAccuracy(double power) {
		return power / ((9 * power) - 2);
	}

    /**
     * Converts degrees to radians.
     */
    public static double degToRad(double degrees) {
    	return degrees * Math.PI / 180;
    }

    /**
     * Converts radians to degrees.
     */
    public static double radToDeg(double radians) {
    	return radians * 180 / Math.PI;
    }
}