Circular Targeting

Description

A method of targeting which assumes that the target will continue moving with the same turn rate and at the same speed.

Example

This is the code used in WaveSurfing Challenge Bot C:

//Add import robocode.util.* for Utils and import java.awt.geom.* for Point2D
//This code goes in your onScannedRobot() event handler

double bulletPower = Math.min(3.0,getEnergy());
double myX = getX();
double myY = getY();
double absoluteBearing = getHeadingRadians() + e.getBearingRadians();
double enemyX = getX() + e.getDistance() * Math.sin(absoluteBearing);
double enemyY = getY() + e.getDistance() * Math.cos(absoluteBearing);
double enemyHeading = e.getHeadingRadians();
double enemyHeadingChange = enemyHeading - oldEnemyHeading;
double enemyVelocity = e.getVelocity();
oldEnemyHeading = enemyHeading;

double deltaTime = 0;
double battleFieldHeight = getBattleFieldHeight(), 
       battleFieldWidth = getBattleFieldWidth();
double predictedX = enemyX, predictedY = enemyY;
while((++deltaTime) * (20.0 - 3.0 * bulletPower) < 
      Point2D.Double.distance(myX, myY, predictedX, predictedY)){		
	predictedX += Math.sin(enemyHeading) * enemyVelocity;
	predictedY += Math.cos(enemyHeading) * enemyVelocity;
	enemyHeading += enemyHeadingChange;
	if(	predictedX < 18.0 
		|| predictedY < 18.0
		|| predictedX > battleFieldWidth - 18.0
		|| predictedY > battleFieldHeight - 18.0){

		predictedX = Math.min(Math.max(18.0, predictedX), 
		    battleFieldWidth - 18.0);	
		predictedY = Math.min(Math.max(18.0, predictedY), 
		    battleFieldHeight - 18.0);
		break;
	}
}
double theta = Utils.normalAbsoluteAngle(Math.atan2(
    predictedX - getX(), predictedY - getY()));

setTurnRadarRightRadians(Utils.normalRelativeAngle(
    absoluteBearing - getRadarHeadingRadians()));
setTurnGunRightRadians(Utils.normalRelativeAngle(
    theta - getGunHeadingRadians()));
fire(3);

See also

• Circular Targeting/Walkthrough - An in-depth example of creating a circular targeting algorithm in Robocode, authored by Dummy.
• Alisdair Owen's circular targeting tutorial with iteration.

Targeting Quick Head-On · Linear · Circular · Random · Mean · Area · Head-Fake Statistical Laser · Avg Bearing Offset · Factored Angular · Visit Count Stats · BestPSpace Log-Based Pattern Matching · Dynamic Clustering Heuristics Neural · FuzzyLogic Hybrid Symbolic Dynamic Segmentation · Zoom Targeting · SmartFactor · Anti-Surfer Firing Angle Bearing Offset · GuessFactor · Play It Forward · Displacement Vector Energy Selecting Fire Power · When To Fire Terms Bullet Travel Time · Waves · Multiple Choice · Max Escape Angle Related Targeting Challenges · Segmentation · Chase Bullets · Virtual Guns · Saving See Also: Category:Targeting