Crabking Cannontower

Based on game build 714014 | Last updated: 2026-03-04

Overview

The crabking_cannontower is a boss-associated environmental prefab functioning as a stationary mortar turret. It is part of the Crab King's defenses and operates autonomously: it scans for boats within range, then targets large creatures or player-associated entities to fire mortar projectiles. It features dynamic health-based damage reduction, reload timing, and visual upgrades based on its red gem count. The component integrates with physics via boat collisions, floating on water, and custom projectile launch logic using the complexprojectile, health, and floater components.

Usage example

-- This prefab is instantiated internally by the game and not typically spawned manually by mods.
-- Example of how its core methods are invoked during gameplay:
local tower = SpawnPrefab("crabking_cannontower")
tower.redgemcount = 8  -- Upgrades mortar visual and damage
tower:UpdateMortarArt()
tower:TryShootCannon()  -- Attempt to fire if loaded

Dependencies & tags

Components used: boatphysics, combat, complexprojectile, floater, follower, health, lootdropper, inspectable
Tags added: cannontower, hostile, crabking_ally, soulless, lunar_aligned, ignorewalkableplatformdrowning, electricdamageimmune

Properties

Property	Type	Default Value	Description
redgemcount	number?	nil	Controls mortar projectile visual level, damage scaling, and size (levels: <=4, 5–7, >=8).
yellowgemcount	number?	nil	Modifies collision damage multiplier when hit by a boat (mult = 0.3/0.6/0.8/1.0 based on thresholds).
reloadtask	Task?	nil	Stores the scheduled reload task; canceled when cannon fires or reload completes.

Main functions

GetShootTargetPosition(target)

• Description: Generates a randomized position near the target, offset up to 6 units radius, to avoid hitting the exact center and allow for spread.
• Parameters: target (Entity) — the entity to target.
• Returns: Vector3 — target position with randomized lateral offset.
• Error states: None; always returns a valid Vector3.

LaunchProjectile(target, projectile_name)

• Description: Spawns and configures a mortarball projectile, calculates launch speed using linear easing based on distance, and sets damage/scaling based on redgemcount.
• Parameters:
  • target (Entity) — the entity being targeted.
  • projectile_name (string?) — optional override for projectile prefab ("mortarball" by default).
• Returns: Entity (projectile instance).
• Error states: If projectile.components.complexprojectile is missing, it adds the component automatically.

TryShootCannon()

• Description: Evaluates targeting priority: boat first (within FIND_BOAT_DIST = 18), then individual creatures or player-allied units (within FIND_TARGET_DIST = 12). Fires if a target is found; otherwise, schedules a reload task.
• Parameters: None.
• Returns: Nothing.
• Error states: Does nothing if not loaded (stategraph empty tag); triggers reload instead.

DoShootCannon(ent)

• Description: Fires a projectile at ent, clears pending reload task, pushes ck_shootcannon event, and initiates reload test.
• Parameters: ent (Entity) — the targeted entity.
• Returns: Nothing.
• Error states: If called while empty, it still attempts to fire and may launch a misaligned projectile.

StartReloadTask(time)

• Description: Schedules TryShootCannon after time seconds. Cancels any existing reload task first.
• Parameters: time (number) — delay in seconds before reloading/attempting to shoot.
• Returns: Nothing.

TestForReload()

• Description: Checks if the tower is empty (sg:HasStateTag("empty")). If so, pushes ck_loadcannon event and schedules a reload (6–10 seconds). Otherwise, rechecks after 1 second.
• Parameters: None.
• Returns: Nothing.

UpdateMortarArt()

• Description: Updates visual overrides (mortar build) and anim state when redgemcount exceeds thresholds (>4, >7).
• Parameters: None.
• Returns: Nothing.

OnSave(inst, data)

• Description: Saves current redgemcount and yellowgemcount to persistence data.
• Parameters:
  • inst (Entity) — the instance being saved.
  • data (table) — the save data table.
• Returns: Nothing.

OnLoad(inst, data)

• Description: Restores redgemcount/yellowgemcount from save data and reapplies visual upgrades.
• Parameters:
  • inst (Entity) — the instance being loaded.
  • data (table?) — the loaded save data (may be nil).
• Returns: Nothing.

Events & listeners

• Listens to:
  • on_collide — triggers collision damage via _OnCollide handler when colliding with a boat.
  • onsink — triggers floater landing logic via _OnSink (if water interacts).
• Pushes:
  • ck_shootcannon — fired after successfully launching a projectile.
  • ck_loadcannon — fired when initiating a reload sequence.