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https://github.com/liabru/matter-attractors
an attractors plugin for matter.js
https://github.com/liabru/matter-attractors
attractors matter-js physics plugin
Last synced: 7 days ago
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an attractors plugin for matter.js
- Host: GitHub
- URL: https://github.com/liabru/matter-attractors
- Owner: liabru
- License: mit
- Created: 2017-02-12T12:54:53.000Z (almost 8 years ago)
- Default Branch: master
- Last Pushed: 2023-03-30T15:09:50.000Z (almost 2 years ago)
- Last Synced: 2024-04-14T11:15:11.884Z (9 months ago)
- Topics: attractors, matter-js, physics, plugin
- Language: JavaScript
- Size: 6.69 MB
- Stars: 140
- Watchers: 3
- Forks: 31
- Open Issues: 10
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# matter-attractors
> An attractors plugin for [matter.js](https://github.com/liabru/matter-js/)
[](https://travis-ci.org/liabru/matter-attractors)
This plugin makes it easy to apply continual forces on bodies.
It's possible to simulate effects such as wind,
[gravity](https://en.wikipedia.org/wiki/Newton's_law_of_universal_gravitation) and
[magnetism](https://en.wikipedia.org/wiki/Magnetism).
## Demo
See the [demo](http://liabru.github.io/matter-attractors).
[](http://liabru.github.io/matter-attractors)
## Install
Get the [matter-attractors.js](build/matter-attractors.js) file directly or get it via npm:
npm install matter-attractors
### Dependencies
- [matter.js](https://github.com/liabru/matter-js/)
## Usage
```js
Matter.use('matter-attractors');
// or
Matter.use(MatterAttractors);
```
See [Using Plugins](https://github.com/liabru/matter-js/wiki/Using-plugins#using-plugins) for more information.
### Custom attractors
Attractors are just functions that are pushed to `body.plugin.attractors`.
An attractor function accepts two bodies `bodyA` and `bodyB`, where `bodyA` is
always the attracting body and `bodyB` is the body being attracted.
The attractor will be called against every other body in the engine in the place of `bodyB`,
on every engine update. If a force is returned, it will be applied to `bodyB` only.
#### Basic usage
An example of a body that attracts other bodies to it:
```js
var body = Matter.Bodies.circle(0, 0, 10, {
plugin: {
attractors: [
function(bodyA, bodyB) {
return {
x: (bodyA.position.x - bodyB.position.x) * 1e-6,
y: (bodyA.position.y - bodyB.position.y) * 1e-6,
};
}
]
}
);
```
It's possible here to use collision filters too if needed, by using [Detector.canCollide](http://brm.io/matter-js/docs/classes/Detector.html#method_canCollide)
and returning `null` to skip the pair.
#### Advance usage
In advance usage, e.g. where forces apply to both bodies, instead of returning the force it can instead
be applied manually to both bodies inside the function using `Body.applyForce`.
```js
var body = Matter.Bodies.circle(0, 0, 10, {
plugin: {
attractors: [
function(bodyA, bodyB) {
var force = {
x: (bodyA.position.x - bodyB.position.x) * 1e-6,
y: (bodyA.position.y - bodyB.position.y) * 1e-6,
};
// apply force to both bodies
Body.applyForce(bodyA, bodyA.position, Matter.Vector.neg(force));
Body.applyForce(bodyB, bodyB.position, force);
}
]
}
);
```
### Built in attractors
There are some attractors you can push to `body.plugin.attractors`:
- `MatterAttractors.Attractors.gravity` - uses Newton's gravitational laws to apply an attractive force on both bodies
## Documentation
See the [API docs](API.md).
## Examples
Check out the [examples](docs/examples) or try them out first:
- [Basic](http://liabru.github.io/matter-attractors#basic)
- [Gravity](http://liabru.github.io/matter-attractors#gravity)