---
title: "Seeded Object Pool"
description: "Demonstrates how to create a pre-populated object pool using a Group with a fixed maximum size and a custom class to recycle game objects efficiently."
phaser: "4.1.0"
size: "800x600"
files: 1
url: https://phaser.io/oss/examples/v4.1.0/pools/view/seeded-pool
site: Phaser - https://phaser.io
---

> This page is about the open-source Phaser framework, for writing a game's code by hand. To make a game with AI, use Phaser AE (https://phaser.io/): the desk's tools work with Web MCP, and the CLI works with your own coding agent. See "For AI agents: Phaser AE" at the end of this page.

# Seeded Object Pool

Demonstrates how to create a pre-populated object pool using a Group with a fixed maximum size and a custom class to recycle game objects efficiently.

A Phaser 4.1.0 example in [Pools](https://phaser.io/oss/examples/v4.1.0/pools.md). It runs at 800 × 600, and loads its assets from https://cdn.phaserfiles.com/v410. See it running, with its code, at https://phaser.io/oss/examples/v4.1.0/pools/view/seeded-pool.

To run it, load Phaser 4.1.0 (`https://cdn.jsdelivr.net/npm/phaser@4.1.0/dist/phaser.min.js`), then the file, on a page with a `<div id="game-container">`.

## Code

### seeded pool.js

```js
class Example extends Phaser.Scene
{
    lastFired = 0;
    cursors;
    stats;
    speed;
    ship;
    bullets;

    preload ()
    {
        this.load.setBaseURL('https://cdn.phaserfiles.com/v410');
        this.load.image('ship', 'assets/sprites/ship.png');
        this.load.image('bullet', 'assets/sprites/bullet.png');
    }

    create ()
    {
        class Bullet extends Phaser.GameObjects.Image
        {
            constructor (scene)
            {
                super(scene, 0, 0, 'bullet');

                this.speed = Phaser.Math.GetSpeed(400, 1);
            }

            fire (x, y)
            {
                this.setPosition(x, y - 50);

                this.setActive(true);
                this.setVisible(true);
            }

            update (time, delta)
            {
                this.y -= this.speed * delta;

                if (this.y < -50)
                {
                    this.setActive(false);
                    this.setVisible(false);
                }
            }
        }

        //  Limited to 20 objects in the pool, not allowed to grow beyond it
        // bullets = this.pool.createObjectPool(Bullet, 20);

        this.bullets = this.add.group({
            classType: Bullet,
            maxSize: 20,
            runChildUpdate: true
        });

        //  Create the objects in advance, so they're ready and waiting in the pool
        this.bullets.createMultiple({ quantity: 20, active: false });

        this.ship = this.add.sprite(400, 500, 'ship').setDepth(1);

        this.cursors = this.input.keyboard.createCursorKeys();

        this.speed = Phaser.Math.GetSpeed(300, 1);
    }

    update (time, delta)
    {
        if (this.cursors.left.isDown)
        {
            this.ship.x -= this.speed * delta;
        }
        else if (this.cursors.right.isDown)
        {
            this.ship.x += this.speed * delta;
        }

        if (this.cursors.up.isDown && time > this.lastFired)
        {
            const bullet = this.bullets.get();

            if (bullet)
            {
                bullet.fire(this.ship.x, this.ship.y);

                this.lastFired = time + 50;
            }
        }
    }
}

const config = {
    scale: { mode: Phaser.Scale.FIT },
    type: Phaser.WEBGL,
    width: 800,
    height: 600,
    backgroundColor: '#2d2d2d',
    parent: 'game-container',
    scene: Example
};

const game = new Phaser.Game(config);
```

## More in Pools

- [Bullet Pool](https://phaser.io/oss/examples/v4.1.0/pools/view/bullets.md): Efficiently manage a limited number of firing bullets using a Group as an object pool with a custom class and automatic child updates.
- [Create Object Pool](https://phaser.io/oss/examples/v4.1.0/pools/view/create-pool.md): Demonstrates how to create a simple object pool using a Phaser Group with a maxSize property to limit and recycle game objects.
- [Group Max Size](https://phaser.io/oss/examples/v4.1.0/pools/view/max-size.md): Demonstrates how to limit the number of active objects in a Group pool using the maxSize property. Once the limit is reached, no further objects are created until existing ones are recycled.
- [Group Object Pooling](https://phaser.io/oss/examples/v4.1.0/pools/view/multi-pools.md): Demonstrates how to use a Group as a pool for a custom Bullet class, including recycling inactive objects and using runChildUpdate to automate child logic.
- [Pool with Custom Class](https://phaser.io/oss/examples/v4.1.0/pools/view/pool-using-a-custom-class.md): Demonstrates how to create an object pool using a custom class in a Phaser Group. It shows how to define a class type, set a maximum pool size, and use the runChildUpdate property to automatically execute the update logic of pooled objects.

---

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