screen-shake
v0.0.5
Published
Screen shake for JavaScript / TypeScript games.
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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
andexponential trauma
for a more satisfying shake - :zap: Around
700b
and0
dependencies - :safety_vest: Fully typed
API
You first need to create an instance by using the default export
import createScreenShake from 'screen-shake'
const screenShake = createScreenShake()
Configuration options
createScreenShake({
// The maximum amount of angle movement.
maxAngle = 10,
// The maximum amount of x offset movement.
maxOffsetX = 30,
// The maximum amount of y offset movement.
maxOffsetY = 30,
// How much trauma is reduced per update. Tweak this if you want to change the duration of the screen shake. A higher value means a shorter duration.
traumaReductionPerUpdate = 0.02,
})
The screen shake instance has two methods:
add
(trauma: number) => void
How much trauma to add between 0 and 1 (equal to 100% trauma).
update
(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 angleoffsetX
- Add it to the cameras x positionoffsetY
- Add it to the cameras y position
Example
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
// Save a copy of the camera at the original position
const baseCamera = {
angle: camera.angle,
x: camera.x
y: camera.y
}
gameLoop(() => {
const { angle, offsetX, offsetY } = screenShake.update(time)
camera.angle = baseCamera.angle + angle
camera.position.x = baseCamera.x + offsetX
camera.position.y = baseCamera.y + offsetY
time++
})
:package: Install
npm install screen-shake
:book: Recipes
Export instance from file
Initialize the screen shake instance in a file and export the instance.
screenShake.ts
import createScreenShake from 'screen-shake'
export default createScreenShake()
Change screen shake speed
Modify time
before passing it to update
Example with 50% speed:
screenShake.update(time * 0.5)