KT-Robots Programming Reference

Pre-Build Lambda-Robots

The lambda-robots/src/main/kotlin/io.onema.ktrobots.lambda/functions/ folder contains additional robots that are deployed, these have different behaviors. Next, we need a few robots to battle it out.

  • TargetRobot: This is a stationary robot for other robots to practice on.
  • YosemiteSam: This robot runs around shooting in random directions as fast as it can.
  • HotShot: This robot uses its radar to find other robots and fire at them. When hit, this robot moves around the board.
  • RoboDog: This robot moves around shooting straight in front of it, when it finds a target it changes direction and chasses it, this robot will do collision damage.

LambdaRobots SDK

Derive your Lambda-Robot from the LambdaRobotFunction provided by the SDK.

Abstract Methods

The base class requires two methods to be implemented:

Method Description
fun getBuild(state: LambdaRobotState): Pair<LambdaRobotBuild, LambdaRobotState> This method returns the robot build information, including its name, armor, engine, missile, and radar types, and the robot state object. Note that a build cannot exceed 8 points by default, or the robot will be disqualified at the beginning of the match.
fun getAction(state: LambdaRobotState): Pair<LambdaRobotAction, LambdaRobotState> This method returns the actions taken by the robot during the turn and the updated robot state


The most commonly needed properties are readily available as properties from the base class. Additional information about the game or the robot is available via the Game and Robot properties, respectively.

Property Type Description
gameInfo GameInfo Game information data structure. See below.
robot LambdaRobot Robot information data structure. See below.

Robot Properties

Property Type Description
arn string Robot invokation identifier, either the AWS Lambda ARN or class namespace + class name.
id string Globally unique robot ID.
index int Index position of robot. Starts at 0.
name string Robot display name.
status LambdaRobotStatus Robot status. Either alive or dead.
x double Robot horizontal position.
y double Robot vertical position.
heading double Robot heading. Between 0 and 360. (degrees)
maxDamage double Maximum damage before the robot is destroyed.
maxSpeed double Engine Maximum speed - armor speed modifier for robot. (m/s)
isAlive() boolean True if the status == LambdaRobotStatus.alive else false
canFire() boolean True if the reloadCoolDown == 0 else false
addDamageDealt() LambdaRobot Increments the count to the totalDamageDealt
addHit() LambdaRobot Increments the count to the totalMissileHitCount
maxTurnSpeed double Maximum speed at which the robot can change heading without a sudden stop. (m/s)
speed double Robot speed. Between 0 and engine.maxSpeed. (m/s)
reloadCoolDown double Number of seconds before the robot can fire another missile. (s)
targetHeading double Desired heading for robot. The heading will be adjusted accordingly every turn. (degrees)
targetSpeed double Desired speed for robot. The current speed will be adjusted accordingly every turn. (m/s)
timeOfDeathGameTurn int Game turn during which the robot died. -1 if robot is alive.
totalCollisions int Number of collisions with walls or other robots during match.
totalDamageDealt double Damage dealt by missiles during match.
totalKills int Number of confirmed kills during match.
totalMissileFiredCount int Number of missiles fired by robot during match.
totalMissileHitCount int Number of missiles that hit a target during match.
totalTravelDistance double Total distance traveled by robot during the match. (m)
damage double Accumulated robot damage. Between 0 and MaxDamage.
armor.deceleration double Deceleration when speeding up. (m/s^2)
armor.collisionDamage double Amount of damage the robot receives from a collision.
armor.directHitDamage double Amount of damage the robot receives from a direct hit.
armor.farHitDamage double Amount of damage the robot receives from a far hit.
armor.nearHitDamage double Amount of damage the robot receives from a near hit.
engine.acceleration double Acceleration when speeding up. (m/s^2)
engine.maxSpeed double Maximum speed for robot. (m/s)
missile.directHitDamageBonus double Bonus damage on target for a direct hit.
missile.farHitDamageBonus double Bonus damage on target for a far hit.
missile.nearHitDamageBonus double Bonus damage on target for a near hit.
missile.range double Maximum range for missile. (m)
missile.reloadCooldown double Number of seconds between each missile launch. (s)
missile.velocity double Travel velocity for missile. (m/s)
radar.maxResolution double Maximum degrees the radar can scan beyond the selected heading. (degrees)
radar.range double Maximum range at which the radar can detect an opponent. (m)

GameInfo Properties

Property Type Description
boardWidth double Width of the game board.
boardHeight double Height of the game board.
secondsPerTurn double Number of seconds elapsed per game turn.
directHitRange double Distance for missile impact to count as direct hit.
nearHitRange double Distance for missile impact to count as near hit.
farHitRange double Distance for missile impact to count as far hit.
collisionRange double Distance between robots to count as a collision.
gameTurn int Current game turn. Starts at 1.
maxGameTurns int Maximum number of turns before the game ends in a draw.
maxBuildPoints int Maximum number of build points a robot can use.
apiUrl string URL for game server API.

LambdaRobotAction Properties

Property Type Description
speed double Update the robot speed up to engine.maxSpeed.
heading double Update the robot heading.
fireMissileHeading double Heading of a new fired missile.
fireMissileDistance double Distance a fired missile can travel up to missile.range.
fired boolean Whether a missile was fired or not.
arrivedAtDestination boolean Whether or not the robot arrived at it’s destination.

Primary Methods

The following methods represent the core capabilities of the robot. They are used to move, fire missiles, and scan their surroundings.

Method ReturnType Description
scan(heading: Double, resolution: Double) ScanEnemiesResponse Scan the game board in a given deading and resolution. The resolution specifies in the scan arc centered on heading with +/- resolution tolerance. The max resolution is limited to Robot.RadarMaxResolution.
angleToXY(x: Double, y: Double) Double Determine the angel in degrees relative to the current robot position. Returns a value between -180 and 180 degrees.
distanceToXY(x: Double, y: Double) Double Determine the distance to X, Y relative to the current robot position.
normalizeAngle(angle: Double) Double Normalize angle to be between -180 and 180.
getNewHeading(minDistanceToEdge: Int = 100) Int Check if the robot needs to turn based on a minimum distance to the edge and return a new heading if it does.

Support extension functions

The following methods are available to make some operations easier:

LambdaRobotAction Extension Functions ReturnType Description
LambdaRobotAction.fireMissile(heading: Double, distance: Double) LambdaRobotAction Fire a missile in a given direction with impact at a given distance. A missile can only be fired if Robot.ReloadCoolDown is 0.
LambdaRobotAction.fireMissileToXY(x: Double, y: Double) LambdaRobotAction Convenience function to fire a missile at a specific set of coordinages.
LambdaRobotAction.moveToXY(x: Double, y: Double) LambdaRobotAction Convenience method to move the robot to a specific location.
LambdaRobotState Extension Functions ReturnType Description
LambdaRobotState.initialize() LambdaRobotState Convenience function to set the state to initialized.

Robot Build

By default, 8 build points are available to allocate in any fashion. The robot is disqualified if its build exceeds the maximum number of build points.



Radar Type Radar Range Radar Resolution Points
ultraShortRange 200 meters 45 degrees 0
shortRange 400 meters 20 degrees 1
midRange 600 meters 10 degrees 2
longRange 800 meters 8 degrees 3
ultraLongRange 1,000 meters 5 degrees 4



Engine Type Max. Speed Acceleration Points
economy 60 m/s 7 m/s^2 0
compact 80 m/s 8 m/s^2 1
standard 100 m/s 10 m/s^2 2
large 120 m/s 12 m/s^2 3
extraLarge 140 m/s 13 m/s^2 4



Armor Type Direct Hit Near Hit Far Hit Collision Max. Speed Deceleration Points
ultraLight 50 25 12 10 +35 m/s 30 m/s^2 0
light 16 8 4 3 +25 m/s 25 m/s^2 1
medium 8 4 2 2 - 20 m/s^2 2
heavy 4 2 1 1 -25 m/s 15 m/s^2 3
ultraHeavy 2 1 0 1 -45 m/s 10 m/s^2 4



When shooting a missile a heading and a range must be set. Depending on the missile, the range cannot exceed the Max. Range. Each missile causes damage only when it reaches its set range, none otherwise. When a missile explodes it can cause up to three types of damage:

Shooting Direct hit damage Near hit damage Far hit damage
shooting direct-hit-damage near-hit-damage far-hit-damage
Missile Type Max. Range Velocity Direct Hit Bonus Near Hit Bonus Far Hit Bonus Cooldown Points
dart 1,200 meters 250 m/s 0 0 0 0.0 sec 0
arrow 900 meters 200 m/s 2 1 0.5 0.5 sec 1
javelin 700 meters 150 m/s 6 3 1 1.0 sec 2
cannon 500 meters 100 m/s 10 8 6 1.5 sec 3
BFG 350 meters 75 m/s 40 20 10 2.0 sec 4
sniperRifle 1200 meters 1750 m/s 30 15 0 4.0 sec 5