Phaser: Physics

This post is part of a Phaser series. Click here to see the first post of the series.

Phaser provides 3 different kinds of built-in physics engines:

• Arcade
• Matter.js
• Impact (Impact.js compatible)

Arcade is the simplest one, and the one I’ll describe right now.

Enable it by adding a physics property to the Phaser.Game initialization config object:

const config = {
  //...
  physics: {
    default: 'arcade',
    arcade: {
      debug: false
    }
  }
}

You can add physics to a single GameObject, like this:

const dog = this.physics.add.sprite(20, 20, 'dog')

or you can create a physics group.

Groups are handy, because we can setup common rules for all the items in a group.

We have 2 kinds of groups: static groups, and dynamic groups. A static group include static bodies, and a dynamic group includes dynamic bodies.

Static bodies are element that never move. Like the ground in a platform game:

//in preload()
this.load.image('ground', 'assets/platform.png')

//in create()
const platforms = this.physics.add.staticGroup()
const ground = this.add.sprite(200, 200, 'ground')
platforms.add(ground)

Note: you can download the asset from https://github.com/photonstorm/phaser3-examples/tree/master/public/assets

A dynamic group includes elements that can move, and have a velocity and speed:

const dogs = this.physics.add.group()

You can add items to a group using items.add().

const dogs = this.physics.add.group()
const dog = this.add.sprite(20, 20, 'dog')
dogs.add(dog)

Groups also provide a handy create() method which we can use to create GameObjects automatically:

platforms.create(200, 200, 'ground')

//instead of
const ground = this.add.sprite(200, 200, 'ground')
platforms.add(ground)

Once you have a physics object set up, you can start working on collisions.