Spawn System

Configure weighted random spawning, alive limits, intervals, and spawn radius with SpawnGroup ScriptableObject assets. Multiple Spawner instances can run independently in the same scene.

Structure

SpawnSystem (pure C# instance)
  - Registers and controls all Spawner instances in the scene

SpawnGroup (ScriptableObject)
  - Entry list (Prefab + Weight + Min/MaxCount)
  - SpawnInterval, MaxAlive, SpawnRadius

Spawner (MonoBehaviour)
  - Instantiates and despawns objects using a SpawnGroup

Quick Start

1. Create a SpawnGroup

Create -> AchUtils/Spawn/Spawn Group

SpawnInterval : 5
MaxAlive      : 10
SpawnRadius   : 8

Entries:
  [0] Prefab: SlimeBlue    Weight: 70   Min: 1  Max: 2
  [1] Prefab: SlimeRed     Weight: 25   Min: 1  Max: 1
  [2] Prefab: SlimeBoss    Weight:  5   Min: 1  Max: 1

2. Place a Spawner

Create an empty scene object and add Spawner.

Field	Description
Group	SpawnGroup asset
Auto Start	Start spawning automatically on scene start

3. Control Spawning

using AchUtils.Spawn;

[SerializeField] Spawner spawner;

spawner.StartSpawning();
spawner.StopSpawning();
spawner.DespawnAll();

spawner.OnSpawned   += obj => Debug.Log($"{obj.name} spawned");
spawner.OnDespawned += obj => Debug.Log($"{obj.name} despawned");

4. Control All Spawners

[SerializeField] Spawner[] spawners;

private SpawnSystem spawnSystem;

void Awake()
{
    spawnSystem = new SpawnSystem(spawners);
}

spawnSystem.StartAll();
spawnSystem.StopAll();
spawnSystem.DespawnAll();

API

Spawner

bool IsSpawning
IReadOnlyList<GameObject> AliveObjects

void StartSpawning()
void StopSpawning()
void DespawnAll()

event Action<GameObject> OnSpawned
event Action<GameObject> OnDespawned

SpawnSystem

SpawnSystem()
SpawnSystem(IEnumerable<Spawner> spawners)

void RegisterSpawner(Spawner spawner)
void UnregisterSpawner(Spawner spawner)

void StartAll()
void StopAll()
void DespawnAll()

IReadOnlyList<Spawner> Spawners

SpawnGroup.Entry

GameObject Prefab
float      Weight
int        MinCount
int        MaxCount

Spawn Logic

1. Run every SpawnInterval.
2. If alive count is below MaxAlive, select an entry with PickRandom().
3. Instantiate Random.Range(Min, Max + 1) objects.
4. Place objects within SpawnRadius using Random.insideUnitCircle.

SpawnGroup.Entry entry = spawnGroup.PickRandom();
var obj = Instantiate(entry.Prefab, spawnPos, Quaternion.identity);

Multiple Spawners

DungeonSpawner    -> SlimeGroup     (5 alive, 3s)
BossRoomSpawner   -> EliteGroup     (2 alive, 10s)
TreasureSpawner   -> ChestGroup     (1 alive, 30s)

Each Spawner is independent and can use different groups and settings.

::: tip Object pooling For high-frequency spawns, connect this system to an object pool through Spawner.OnSpawned and OnDespawned. :::