# Wall avoidance

Fragment of a discussion from Talk:Talon/source
```package cs;

import java.awt.geom.Point2D;
import robocode.ScannedRobotEvent;
import robocode.util.Utils;

/**
* Talon - a Nano Melee robot by Chase
*
* The idea is to avoid driving toward enemy robots, nearer ones are more
* dangerous to drive towards.
*
* Codesize: 248
*/
public class Talon extends AdvancedRobot {
private static Point2D.Double[] map = new Point2D.Double[10];
private static int n;

public void run() {
//setAdjustGunForRobotTurn(true); //Sheldor: In melee this doesn't really matter.
//setAllColors(Color.RED); //Sheldor: I'm very sorry. :(
double angle, bestDanger, danger;
while(true) {

setAhead((bestDanger = angle = 360) - (5 * getTurnRemaining())); //Sheldor: Slowing down before making big turns makes the wall avoidance much better.

while(angle-- > 0) {
int t;
setFire(t = getOthers()); //Sheldor: From Graviton.

//Sheldor: Drive toward the center of the field when the bot gets near a wall.
//This will only work properly on a 1000/1000 pixel field.
danger = -Math.abs(Utils.normalRelativeAngleDegrees(angle - Math.toDegrees(Math.atan2(getX() - 500, getY() - 500)))) *
(table.charAt((int)getX()) + table.charAt((int)getY()));

try {
while(true) {
// our most recent scans, unfortunately not enough room
// to project them
Point2D.Double v;
// set our gun to face this nearest enemy
// the difference between current angle we are
// considering and the enemy
// multiply it by how close they are, closer is more
// dangerous to move towards
danger += 1 / (Math.abs(Utils.normalRelativeAngleDegrees(angle - v.y))) / v.x; //Sheldor: "X / Y" has exactly the same effect as "X * (1 / Y)" but is ~3 bytes smaller.
}
} catch(Exception e) {
// We don't have room for any kind of sanity checks, also
// the only way to get out of the loop without
// having to have a comparison, saves us some code size
}
if(danger < bestDanger) {
bestDanger = danger;
}
}
// Turning it by only 1 saves us some code size but in radians this
// value > PI/4 the maximum
// turn the radar can turn, meaning it will cover the full arc as
// long as we call it every turn.
}
}

public void onScannedRobot(ScannedRobotEvent e) {
try {
// Set the most recent scan into our map of enemies
map[--n] = new Point2D.Double(e.getDistance(), getHeading() + e.getBearing());
}
catch(Exception ex) {
// attempted to scan but it failed, set the number of enemies again
// we miss an enemy scan but we gain some code size here
n = getOthers();
}
}

static final String table = "\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064" +
"\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0001" +
"\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001" +
"\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" +
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" +
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" +
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" +
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" +
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" +
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" +
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" +
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" +
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" +
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" +
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\u0001\u0001\u0001\u0001\u0001" +
"\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001" +
"\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064" +
"\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064" +
"\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064\u0064";
}```
Sheldor17:10, 22 February 2013