screen-shake

> Screen shake for JavaScript / TypeScript games

Based on this GDC talk by Squirrel Eiserloh

:sparkles: Features

- :+1: Works with any JS/TS rendering library or game engine
- :yum: Uses Perlin noise and exponential trauma for a more satisfying shake
- :zap: Around 700b and 0 dependencies
- :safety_vest: Fully typed
- :seedling: Seeded

API

You first need to create an instance by using the default export

``ts
import createScreenShake from 'screen-shake'

const screenShake = createScreenShake()
`

Configuration options

`ts
createScreenShake({
// The maximum amount of angle movement.
maxAngle = 12,
// The maximum amount of x offset movement.
maxOffsetX = 70,
// The maximum amount of y offset movement.
maxOffsetY = 70,
// The amount of updates until trauma goes from 1 to 0
duration = 28,
speed = 0.4,
// Set this for a predictable screen shake (useful for tests)
seed,
})
`

The screen shake instance has two methods:

$3

(trauma: number) => void

How much trauma to add between 0 and 1 (equal to 100% trauma).

$3

(time: number) => ({ angle: number, offsetX: number, offsetY: number })

Call this on every update of your game loop.

Has one argument, the time since update was first called. (This is used to smoothly interpolate the noise)

Returns an object with the values to add to your camera:

- angle - Add it to the cameras angle
- offsetX - Add it to the cameras x position
- offsetY - Add it to the cameras y position

$3

`ts
import createScreenShake from 'screen-shake'

// Create the instance. Configuration is optional.
const screenShake = createScreenShake()

if (projectileHit) {
// Add 10% trauma when hit
screenShake.add(0.1)
}

let time = 1

gameLoop(() => {
const { angle, offsetX, offsetY } = screenShake.update(time)

camera.angle = camera.angle + angle
camera.position.x = camera.x + offsetX
camera.position.y = camera.y + offsetY

time++
})
`

:package: Install

`console
npm install screen-shake
``