Robocode Library

Robocode Tank Royale Java API v0.30.2 — Function & Event Reference

How to use this doc  Each heading is a function or event class. – Description explains what it does. – Example is a minimal Java snippet you can paste into your bot.

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✅ Core Bot Methods

Movement & Body Control

forward(double distance)

Moves the bot forward until the distance is reached or a wall/robot stops it.

forward(150);

back(double distance)

Moves the bot backwards.

back(75);

turnLeft(double degrees) / turnRight(double degrees)

Rotate the body counter‑clockwise / clockwise.

turnLeft(90);

turnGunLeft(double degrees) / turnGunRight(double degrees)

Rotate only the gun.

turnGunRight(45);

turnRadarLeft(double degrees) / turnRadarRight(double degrees)

Rotate the radar dish.

turnRadarRight(360);   // full sweep

fire(double power)

Fire a bullet. power ∈ [0.1 … 3].

if (getGunHeat()==0) fire(2.0);

rescan()

Trigger a radar scan immediately.

rescan();

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Utility & Introspection

• getGunTurnRemaining() – degrees left for gun to finish turning
• getRadarTurnRemaining() – degrees left for radar
• getTurnRemaining() – body turn remainder
• getDistanceRemaining() – outstanding move distance
• isRunning() – true while bot is alive
• calcBulletSpeed(double power) – returns speed (20 – 3 × power)
• calcGunHeat(double power) – heat added by a shot (1 + power/5)
• clearEvents() – flush the event queue
• broadcastTeamMessage(Object msg) – send JSON‑serialisable data to teammates

double bulletTime = opponentDist / calcBulletSpeed(1.8);

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State Accessors (BaseBot / BotState)

getEnergy();      // current energy
getX(); getY();   // position (centre)
getDirection();   // body heading (°)
getGunDirection();
getRadarDirection();
getGunHeat();
getSpeed();

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Bullet Information (BulletState)

• getBulletId()
• getOwnerId()
• getPower() / getSpeed()
• getDirection()
• getX() / getY()

for (BulletState b : getBulletStates()) {
    System.out.printf("Bullet %d @ %.0f,%.0f%n", b.getBulletId(), b.getX(), b.getY());
}

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🚨 Event Classes & Handlers

Override the matching on…Event method in your bot. Priorities shown are defaults from DefaultEventPriority (higher fires first).

WonRoundEvent (150)

Round finished and you were last survivor.

@Override public void onWonRound(WonRoundEvent e) {
    System.out.println("I won round " + e.getRoundNumber());
}

TickEvent (100)

Occurs every game tick. Keep logic lightweight to avoid skipped turns.

@Override public void onTick(TickEvent e) {
    if (e.getTurnNumber() % 10 == 0) rescan();
}

ScannedBotEvent (80)

Radar spotted an opponent.

@Override public void onScannedBot(ScannedBotEvent e) {
    double abs = getRadarDirection() + e.getBearing();
    turnGunRight(normalizeBearing(abs - getGunDirection()));
    if (getGunHeat()==0) fire(3);
}

HitByBulletEvent (70)

You were hit.

@Override public void onHitByBullet(HitByBulletEvent e) {
    setBack(100);
    setTurnRight(45);
    go(); // run queued commands
}

BulletHitBotEvent (70)

Your bullet struck another bot.

@Override public void onBulletHitBot(BulletHitBotEvent e) {
    System.out.println("Damage="+ e.getDamage());
}

BulletFiredEvent (70)

Confirmation shot left barrel.

@Override public void onBulletFired(BulletFiredEvent e) {
    lastId = e.getBulletState().getBulletId();
}

BulletHitWallEvent (60)

Your bullet hit the arena wall.

HitBotEvent (50)

Physical collision with another bot.

SkippedTurnEvent (50)

Bot exceeded time budget in previous tick – optimise your code!

CustomEvent (60)

User‑defined Condition became true.

addCustomEvent(() -> getEnergy() < 10);
@Override public void onCustomEvent(CustomEvent e) {
    setMaxSpeed(8);
    back(150);
}

HitWallEvent (40)

Body collided with arena border.

BotDeathEvent (30)

Another bot died.

TeamMessageEvent (20)

Teammate sent message via broadcastTeamMessage.

@Override public void onTeamMessage(TeamMessageEvent e) {
    System.out.println("Msg from " + e.getSenderId() + ": " + e.getMessage());
}

DeathEvent (10)

Your bot died – last chance to log stats.

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🛰 Quick‑Start Mini Bot

public class SpinAndShoot extends Bot {
    @Override public void run() {
        setBodyColor(Color.CYAN);
        while (isRunning()) {
            turnRadarRight(360);   // continuous sweep
        }
    }
 
    @Override public void onScannedBot(ScannedBotEvent e) {
        double abs = getRadarDirection() + e.getBearing();
        turnGunRight(normalizeBearing(abs - getGunDirection()));
        if (getGunHeat()==0) fire(Math.min(3, 400/e.getDistance()));
    }
}

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More resources

• Full Javadoc → https://robocode-dev.github.io/tank-royale/api/java/
• Sample bots → check the samples directory in the course repo.

Happy coding & good luck in the arena! 🚀