Bopit

Simple, quick, AABB framework-independent, collision system. We do rectangles only.

$3

* Bopit only does axis-aligned bounding-box (AABB) collisions. If you need anything
more complicated than that (circles, polygons, etc.) use another library.
* Handles tunnelling - all items are treated as "bullets". The fact that we only
use AABBs allows doing this fast.
* Strives to be fast while being economic in resources
It's centered on detection, but it also offers some (minimal & basic) collision response*
* Can also return the items that touch a point, a segment or a rectangular zone.
* Bopit is _gameistic_ instead of realistic.

Usage

World

``
import {World, Body} from 'bopit'

const world = new World()
const body = new Body(0, 0, 10, 10)
body.add(world)
`

$3

Creates a new virtual space for tracking physical interactions split into cells.

Parameters
- cellSize Is an optional number. It defaults to 64. It represents the size of
the sides of the (squared) cells that will be used internally to provide the data.
In tile based games, it's usually a multiple of the tile side size. So in a game
where tiles are 32x32, cellSize will be 32, 64 or 128. In more sparse games,
it can be higher.

Returns
- World

$3

Queries a rectangle in the world space and will return any bodies that are within
that area.

Parameters
- x x coordinate, Number
- y y coordinate, Number
- width width of the rectangle, Number
- height height of the rectangle, Number

Returns
- [Body] an array of Bodies, will return an empty array if none found

$3

Queries a single point in the world and will return any bodies under that point.

Parameters
- x x coordinate, Number
- y y coordinate, Number

Returns
- [Body] an array of Bodies, will return an empty array if none found

$3

Queries a line through the space and will return any bodies that are on that line.

Parameters
- x x coordinate, Number
- y y coordinate, Number

Returns
- [Body] an array of Bodies, will return an empty array if none found

---

$3

Creates a new physical, rectangular object that can collide with other things.

Parameters
- x x coordinate, Number
- y y coordinate, Number
- width width of the rectangle, Number
- height height of the rectangle, Number

Returns
- Body

$3

Adds the body to a world

$3

Removes the body from the world that it is in.

$3

Will check the collisions and update the position of the body after the collisions

Parameters
- x x coordinate, Number
- y y coordinate, Number
- filter Function(body, collision, goalX, goalY)
- body the body that the check has been run on.
- collision the collision currently in progress
- goalX x position of where the body is headed
- goalY y position of where the body is headed

Returns
- finalX the final x resting spot after collisions
- finalY the final y resting spot after collisions
- collisions all of the collision data from collisions that happened along the way

$3


Same as move but without changing the body. This is good for checking before moving.

$3

Returns the distance from one body to another

---

Example

Try out the example by running npm i && npm start in the example directory and
then opening http://localhost:8080

`
import {World, Body} from 'bopit'
const world = new World(32)
const body = new Body(120, 120, 20, 20)
body.add(world)
const wall1 = new Body(100, 100, 400, 10, true)
wall1.add(world)

const [finalX, finalY, collisions] = body.move(body.x - 10, body.y - 10)
`

Thanks to

- kikito` https://github.com/kikito/bump.lua for writing such an awesome library
that I keep re-writing it in other languages.