https://github.com/hackergrrl/game-camera-2d
:movie_camera: A simple 2D camera that's suited for games.
https://github.com/hackergrrl/game-camera-2d
Last synced: 10 days ago
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:movie_camera: A simple 2D camera that's suited for games.
- Host: GitHub
- URL: https://github.com/hackergrrl/game-camera-2d
- Owner: hackergrrl
- License: mit
- Created: 2015-11-17T02:07:28.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2015-11-17T02:24:48.000Z (over 9 years ago)
- Last Synced: 2025-04-05T18:52:59.575Z (3 months ago)
- Language: JavaScript
- Homepage:
- Size: 7.81 KB
- Stars: 2
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# game-camera-2d
> A simple 2D camera suited for games.
# Install
```bash
$ npm install game-camera-2d
```
# Usage
```js
var camera = createCamera({
left: 0,
right: 640,
top: 0,
bottom: 480
})
camera.setTranslation(64, 64)
camera.setRotation(Math.PI / 4)
camera.setScale(0.5)
var matrix = camera.getMatrix()
console.dir(matrix)
```
outputs a 3x3 matrix compatible with
[gl-mat3](https://www.npmjs.com/package/gl-mat3):
```
Float32Array {
'0': 0.0011048543965443969,
'1': -0.001473139156587422,
'2': 0,
'3': -0.0011048543965443969,
'4': -0.001473139156587422,
'5': 0,
'6': 0,
'7': 0.18856181204319,
'8': 1 }
```
# API
## var camera = require('game-camera-2d')(options)
Creates a new camera object. The `options` object contains the following
optional parameters:
- `left` - the coordinate of the left side of the screen.
- `right` - the coordinate of the right side of the screen.
- `top` - the coordinate of the top of the screen.
- `bottom` - the coordinate of the bottom of the screen.
- `x` - the X coordinate to centre the camera on.
- `y` - the Y coordinate to centre the camera on.
- `angle` - the rotation to apply around the screen centre.
- `scale` - the scaling factor to apply.
## Properties
### camera.width, camera.height
Width and height of the camera viewport, in units.
### camera.x, camera.y
The camera's current X/Y offset from the origin.
### camera.rotation
The rotation of the camera viewport, in radians.
### camera.scale
The scaling factor of the camera.
## Methods
### camera.getMatrix([out])
Retrieves the current state of the camera matrix.
`out` is a length 9 array which receives the result of the computation if not
otherwise specified.
**Returns** The resulting camera matrix
### camera.setTranslation(x, y)
Sets the X/Y offset from the origin for the camera to be centred on.
### camera.setRotation(angle)
Sets the rotation around the translation coordinates, in radians.
### camera.setScale(scale)
Sets the scaling factor of the camera at the translation coordinates.
## Additional Credit
Heavily inspired by Mikola Lysenko's
[camera-2d](https://github.com/mikolalysenko/camera-2d) module.
I really liked the idea of a lightweight 2D camera that spits out a 3x3
transformation matrix, but wanted an API that made both absolute and relative
operations easy.