Object Pooling

To make your game more efficient and run smoother, you will likely want to use object pooling for objects that are often created and destroyed, such as projectiles, explosions and temporary effects. This avoids lag and unnecessary garbage collection, which occurs when objects are destroyed in the scene and slows down your game.

Scene Setup

Simply add a Pool Manager component anywhere in your scene. This is a singleton, which means there should only be one of them in the scene at any time.

The pool manager can be accessed from anywhere in the scene very easily using the PoolManager.Instance reference.

Spawn A Pooled Object

The easiest way to spawn a pooled object is to use the Pool Manager's Get function and pass a prefab reference. This function will create an object pool for the prefab (if it doesn't already exist), and return one item at the specified position and rotation (there is also an optional parameter for setting the item's parent transform);

// Get a pooled object at a specified position and rotation
PoolManager.Instance.Get(myPrefab, somePosition, someRotation);

It's also possible to get a pooled object by name, if the prefab exists in a Resources folder. Here's an example for a prefab named 'Projectile'.

// Get a pooled instance of the prefab named 'Projectile' in a Resources folder
PoolManager.Instance.Get("Projectile", somePosition, someRotation);

Returning An Object To The Pool

To return an item to the pool, simply deactivate its game object. This will make it available for other scripts to use.

The UVC kits include a Deactivate After Lifetime component, which can be used on projectiles, hit effects and other effects to disable them a specified time after they are spawned to return them to the pool.

Setting Up Object Pools

When you get an object for the first time from the pool manager, it creates an object pool. When this happens, it may affect performance, because several items are created for the pool.

To avoid this, you can manually create your own object pools in a scene with a specified number of starting units. The pool manager will automatically find and use them, avoiding that first-time glitch.

To create an object pool:

1. Create a new game object in the scene and add an Object Pool component to it.

2. Drag a prefab into the Prefab property in the inspector.

3. Set the number of default units in the inspector. This is how many will be created at the start.

This pool will be used by the Pool Manager when something needs to spawn the prefab.