Robocode/Game Physics

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Robocode Game Physics

This page describes the game physics of Robocode

Coordinates and Direction Conventions

Coordinates System:	Robocode is using the Cartesian Coordinate System, which means that that the (0, 0) coordinate is located in the buttom left of the battle field.
Clockwise Direction:	Robocode is using a clockwise direction convension where 0 / 360 deg is towards "North", 90 deg towards "East", 180 deg towards "South", and 270 deg towards "West".

Figure 1: http://www.ibm.com/developerworks/java/library/j-robocode2/fig2.gif

Time and distance measurements in Robocode

Time (t):	Robocode time is measured in "ticks". Each robot gets one turn per tick. 1 tick = 1 turn.
Distance Measurement:	Robocode's units are basically measured in pixels, with two exceptions. First, all distances are measured with double precision, so you can actually move a fraction of a pixel. Second, Robocode automatically scales down battles to fit on the screen. In this case, the unit of distance is actually smaller than a pixel.

Robot Movement Physics

Acceleration (a):	Robots accelerate at the rate of 1 pixel/turn. Robots decelerate at the rate of 2 pixels/turn. Robocode determines acceleration for you, based on the distance you are trying to move.
Velocity Equation(v):	v = at. Velocity can never exceed 8 pixels/turn. Note that technically, velocity is a vector, but in Robocode we simply assume the direction of the vector to be the robot's heading.
Distance Equation (d):	d = vt. That is, distance = velocity * time

Robot, Gun, and Radar rotation

Max rate of rotation of robot:	(10 - 0.75 * abs(velocity)) deg / turn. The faster you're moving, the slower you turn.
Max rate of rotation of gun:	20 deg / turn. This is added to the current rate of rotation of the robot.
Max rate of rotation of radar:	45 deg / turn. This is added to the current rate of rotation of the gun.

Bullets

Damage:	4 * firepower. If firepower > 1, it does an additional damage = 2 * (power - 1).
Velocity:	20 - 3 * firepower.
GunHeat generated:	1 + firepower / 5. You cannot fire if gunHeat > 0. All guns are hot at the start of each round.
Power returned on hit:	3 * firepower.

Collisions

With Another Robot:	Each robot takes 0.6 damage. If a robot is moving away from the collision, it will not be stopped.
With a Wall:	AdvancedRobots take abs(velocity) * 0.5 - 1; (Never < 0).

Robocode Processing Loop

The order that Robocode runs is as follows:

1. Battle view is (re)painted
2. All robots execute their code until they take action (and then paused)
3. Time is updated (time = time + 1)
4. All bullets move and check for collisions
5. All robots move (heading, accelration, velocity, distance, in that order)
6. All robots perform scans (and collect team messages)
7. All robots are resumed to take new action
8. Each robot is processing its event queue