Robocode Position04

I completed position04 a little while ago and it's been a while since I've used trig functions.  The most time was spent wrapping my head around radians again.

I'm quite proud of the code since it took a lot of diagramming and trial and error.  It's a pretty trivial task (moving a robot to the middle of the battlefield), but it still took a while.

I was trying for a while to use the getBearing() function, but this requires an event and I looked up a few items on creating custom events, but gave up and decided to go with the brute math instead.

Something I want to look at later is using the least amount of turning to position the robot to face the center.  As it is now, the robot rotates to a heading of 0 degrees before doing anything (this is to normalize the heading to a known heading of 0).

********************************************************************************
package kgl;

import robocode.Robot;

/**
* Position 04 Robot
*
* Move to the center of the playing field, spin around in a circle,  and stop.
*
* @class  ICS 413
* @author Kevin Leong
* @date   9/2/10
*/

public class Position04 extends Robot{

 public void run(){
     //Get battlefield dimensions
     double width = getBattleFieldWidth();
     double height = getBattleFieldHeight();
  
     //Assign coordinates for center and starting position 'current'
     Position center = new Position(width/2, height/2);
     Position current = new Position(getX(), getY());
          
     //Get starting heading
     double currentHeading = getHeading();
  
     //Calculate the Distance and angle from the starting point to the center of the
     //battlefield
     DistanceAngle ad = current.angleDistanceBetweenTwoPoints(center);
  
     //Align to 0 degrees
     turnRight(360-currentHeading);
  
     //Turn the robot to face toward the center
     turnRight(ad.angle);
  
     //Move Robot ahead the correct distance
     ahead(ad.distance);
  
     //Spin - We're Done!
     turnRight(360);
 }
}

/**
* Position Class to store position of center and starting position
* as coordinates.  Also calculates:
*
*  - Distance between two points
*  - Angle between two points in degrees
*/
class Position{
 double x;
 double y;

 public Position(double x, double y){
     this.x = x;
     this.y = y;
 }

 DistanceAngle angleDistanceBetweenTwoPoints(Position p){
     double a = this.x - p.x;
     double b = this.y - p.y;
  
     //Calculate distance using Pythagorean Theorem
     double distance = Math.sqrt(Math.pow(a, 2) + Math.pow(b,2));
  
     //Angle variables for converting angle to degrees
     double angleRadians, angleDegrees;

     //Get angle in radians to center
     angleRadians = Math.atan(a/b);
     System.out.println("AngleRadians: " + angleRadians);
  
     //Convert radians to degrees.  This represents angle
     //if robot starts in quadrant III or IV (below the center of the battlefield)
     angleDegrees = 180 * angleRadians/Math.PI;
  
     //If robot starts in quadrant I or II
     if(b > 0){
         angleDegrees = (180 - Math.abs(angleDegrees));
      
         //If we are in quadrant I
         if(a > 0){
             angleDegrees *= -1;
         }
     }
  
     return new DistanceAngle(distance, angleDegrees);
 }
  
}

/**
* Object to hold calculations on Distance and Angle
* Calculated in the Position Class
*/
class DistanceAngle{
 double distance;
 double angle;

 public DistanceAngle(double distance, double angle){
     this.distance = distance;
     this.angle = angle;
 }
}