Is this a sensible way to do it?

My AdvancedRobot, Thor, is currently using a static boolean "scanning" to determine whether to turn the radar or not.

This should provide a degree of locking by setting "scanning" to false when we scan a robot, setting it to "true" after we execute, and turning if it's true.

I know it's a naive approach and doesn't lock very well, but it doesn't appear to lock -at all- currently.

Is it my methodology that's flawed, or should I hunt for a bug in the code? (No point debugging if I'm going about it the wrong way from the start).

I think the way most of us do it is to simply scan towards the last known location of the enemy every single tick, making sure we overshoot by a little bit in case they move. I've never put too much effort into radar myself (at least 1v1 radar), because extremely simple solutions tend to work perfectly...

You need to turn it every tick, it's just a question of clockwise or counter-clockwise. The area covered by the sweep of the radar from last tick to this tick is the area that is scanned. So once you scan, you want to reverse the direction you turn the radar, not stop turning it.

Edit: Also, there's an option in Robocode to display the radar arcs, which would help you see exactly what's going on.

Ah, so I need to refactor "scanning" to function more as a "turn radar left" boolean (if true, turn radar left, if false turn right) and then just toggle it when I find a robot, would that work?

Yep, that would work fine. That kind of scan type is known as an 'Infinity lock' - there's more on it here: One_on_One_Radar. That kind of radar algorithm will skip scans occasionally, so there are a few others on that page which are usually used on bots that aren't in severely limited codesize tournaments. Personally, I recommend the 'turn multiplier lock', it works perfectly and is quick and easy to implement.

Wow, that one is excellent. I'm not quite grokking it yet, but experiments have shown that it performs much smoother than my previous implementation.

Now to get the gun to point in the right direction.

I've implemented a function, "turnGunTo" which (in theory) turns the gun to a given (absolute) heading. I'm struggling to get it to work, though, as the gun just appears to spin continuously. Here's my function:

	public void turnGunTo(double newHeading) {
		double oldHeading = getGunHeadingRadians(); 
		// use of normalRelativeAngle means we don't have to decide left or right
		setTurnGunLeft(Utils.normalRelativeAngle(calculateTurnAmount(newHeading,oldHeading)));
	}

And, for reference, the calculateTurnAmount() function:

	public double calculateTurnAmount(double newHeading,double oldHeading) {
		// turn amount is a segment of a full circle, calculated by (circle - leftAngle) + rightAngle;
		return (FULL_CIRCLE - Math.max(newHeading, oldHeading)) + Math.min(newHeading, oldHeading);
	}

What am I doing wrong? Also, is the method abstraction superfluous? It seems so, but in some ways it makes it a little bit more semantically-obvious what I'm trying to achieve.