Difference between revisions of "Circular Targeting"

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[[Category:Simple Targeting Strategies]]
 
[[Category:Simple Targeting Strategies]]
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[[Category:Code Snippets]]

Revision as of 06:18, 13 November 2007

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