Wave Trigger

Runtime Spawner includes a complete wave spawning system suitable for tower defense–style gameplay, horde modes, ambushes, and scripted “hold & defend” encounters (e.g., Left 4 Dead–style events).

A WaveTrigger defines when a wave sequence begins. The activation volume is defined by a BoxCollider set as a trigger.

Creating a Wave Trigger

To create a new Wave Trigger:

Open the Runtime Spawner inspector.
Click the “+” button in the Wave Triggers section.

This will:

Create a child GameObject
Add a WaveTrigger
Add and configure a BoxCollider (set to isTrigger = true)

Note WaveTriggers and WaveSpawnPoints do not need to be children of RuntimeSpawner (since 1.3.0). They can live in additively loaded scenes, prefabs, or procedural tiles added at runtime.

Fundamentals

WaveTrigger is an activation component, not a spawner.

It does not spawn enemies directly. Instead, it:

Detects when a wave should begin
Routes activation through the RuntimeSpawner
Manages trigger state, reactivation, and events
Provides designer-friendly UnityEvents and system-level C# events

Use a WaveTrigger to drive:

Scripted wave encounters (hordes, ambushes, defenses)
One-shot or repeatable combat arenas
Waves that start on player approach
Waves that start automatically at level start
Networked encounters driven deterministically by authority

Requirements

A BoxCollider on the same GameObject
BoxCollider.isTrigger = true
A RuntimeSpawner must exist in the scene
A WaveSpawner asset must be assigned
The collider is auto-assigned to TriggerZone in OnEnable()

For trigger events to fire in UnityPhysics mode:

At least one collider must have a Rigidbody (usually the player)

Responsibilities

WaveTrigger is responsible for:

Detecting activation conditions (UnityPhysics or External)
Starting and stopping wave sequences via RuntimeSpawner
Tracking whether the trigger is currently activated
Optionally rearming itself after a cooldown
Exposing UnityEvents and static events for gameplay systems
Providing optional spawn anchors (WaveSpawnPoints)

Key Properties

Trigger & State

BoxCollider TriggerZone The collider used as the activation volume. Auto-assigned and configured in OnEnable().

bool IsActivated (read-only externally) Indicates whether the wave trigger is currently active.

true while a wave sequence is running
Set internally by the trigger lifecycle
Cannot be set directly by external systems

bool IsInside Whether the trigger volume is currently occupied (inside state). Used for trigger events and external driver replication.

int ActiveWave Current wave index (0-based). Managed by the wave runner / RuntimeSpawner.

Wave Configuration

WaveSpawner WaveSpawner The wave table used when this trigger activates. Must be assigned for the trigger to function.

List<WaveSpawnPoint> WaveSpawnPoints Optional anchor points used during wave spawning.

When present:

Spawn locations are chosen from these anchors
Selection is handled by the wave system

Activation & Reactivation (Inspector)

bool startAutomatically When enabled, the trigger activates automatically once:

RuntimeSpawner is initialized, and
WaveTrigger has started

Useful for:

Survival mode openers
Scripted intro fights

bool reactivateTrigger If enabled, the trigger will reset after a cooldown and can activate again.

float reactivateTime Cooldown time (seconds) before the trigger becomes eligible again.

Trigger Driver Mode (New in 1.6.0)

ActivationMode

UnityPhysics – Uses OnTriggerEnter/Exit
External – Trigger is driven by an external system (Fusion / PUN)

This allows WaveTrigger to be used safely in networked games.

Public API (Designers & Drivers)

WaveTrigger is now API-driven. External systems must not mutate internal state directly.

Starting a Wave

waveTrigger.StartWave();

This is the canonical activation path. It routes through RuntimeSpawner.ActivateWaveTrigger(this) and updates state/events consistently.

Stopping a Wave

waveTrigger.StopWave();

External Activation (Networking)

waveTrigger.ExternalActivate(scheduleLocalReset: false);

Use this from authoritative networking drivers.

External Reset (Deterministic)

waveTrigger.ExternalReset();

Cancels any local reset coroutine and returns the trigger to an eligible state.

External Occupancy (Replication)

waveTrigger.SetTriggerInside(true);  // enter
waveTrigger.SetTriggerInside(false); // exit

Used by Fusion / PUN drivers to replicate trigger presence deterministically.

Events

Static C# Events (Systems)

public static event Action<WaveTrigger> onWaveTriggerActivated;
public static event Action<WaveTrigger> onWaveTriggerReset;

Use these for:

Global encounter tracking
Director systems
UI/audio managers without scene references

UnityEvents – Trigger Occupancy

OnTriggerEnterEvent
OnTriggerStayEvent
OnTriggerExitEvent
OnTriggerStateChanged(bool inside)

These emulate trigger-style behavior and are useful for:

FX
Sensors
Debug visualizations

UnityEvents – Wave Lifecycle

OnWaveActivated
OnWaveCompleted
OnWaveDeactivated
OnWaveReset

Use these for:

Locking doors
Starting music
Updating UI
Progression hooks

Runtime Behavior & Lifecycle

Initialization & Registration

OnEnable

Assigns TriggerZone
Resets local state
Subscribes to RuntimeSpawner.onSpawnerInit

Start (Play Mode)

Finds RuntimeSpawner
Registers via RegisterWaveTrigger(this)
Optionally auto-starts if startAutomatically is enabled

OnDisable / OnDestroy

Unsubscribes from spawner events
Unregisters from RuntimeSpawner

Activation Flow

UnityPhysics Mode

OnTriggerEnter checks:
- Correct tag
- Spawner initialized
- Not already activated
Calls StartWave()
Optionally schedules reset

External Mode

Unity triggers are ignored
External driver:
- Sets inside state
- Decides when to activate/reset
- Calls public API methods

Reactivation

If reactivateTrigger is enabled:

Trigger schedules a reset after reactivateTime
On reset:
- IsActivated becomes false
- Reset events fire
- Trigger becomes eligible again

Typical Usage Patterns

1. One-Shot Encounter Volume

startAutomatically = false
reactivateTrigger = false

Player enters:

Trigger activates
Wave plays once
Trigger never fires again

2. Repeatable Horde Zone

reactivateTrigger = true
reactivateTime = 30

Player enters:

Wave starts
After completion + cooldown, trigger resets
Can be reactivated on re-entry

3. Auto-Start Survival Wave

startAutomatically = true
Optional reactivation

On play:

Trigger waits for RuntimeSpawner
Wave starts automatically
No collider required

4. Manual Activation via Script (Updated)

using UnityEngine;
using MegaCrush.Spawner;

public class WaveConsole : MonoBehaviour
{
    [SerializeField] private WaveTrigger trigger;

    public void ActivateFromConsole()
    {
        if (!trigger) return;
        trigger.StartWave();
    }
}

This uses the same internal path as volume-based activation.

5. Global Monitoring (UI / Audio / Director)

using UnityEngine;
using MegaCrush.Spawner;

public class WaveTriggerMonitor : MonoBehaviour
{
    private void OnEnable()
    {
        WaveTrigger.onWaveTriggerActivated += OnActivated;
        WaveTrigger.onWaveTriggerReset += OnReset;
    }

    private void OnDisable()
    {
        WaveTrigger.onWaveTriggerActivated -= OnActivated;
        WaveTrigger.onWaveTriggerReset -= OnReset;
    }

    private void OnActivated(WaveTrigger trigger)
    {
        Debug.Log($"Wave started: {trigger.name}");
    }

    private void OnReset(WaveTrigger trigger)
    {
        Debug.Log($"Wave reset: {trigger.name}");
    }
}

Editor Helpers

AddSpawnpoint() Creates a new child WaveSpawnPoint and selects it.

ShowHide(bool) Controls whether the trigger volume gizmo is drawn.

OnDrawGizmos

Draws the trigger volume
Uses a distinct color when activated

Key Takeaways (1.6.0)

WaveTrigger is now API-driven, not state-mutable
Supports offline-first + deterministic networking
Clear separation between:
- Occupancy (inside)
- Activation (wave lifecycle)
Rich UnityEvents for designers
Clean integration path for Fusion and PUN drivers

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Last updated 7 days ago