https://github.com/hackergrrl/collide-2d-aabb-tilemap
:collision: Collision handling for bounding boxes and a tile map.
https://github.com/hackergrrl/collide-2d-aabb-tilemap
Last synced: 6 months ago
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:collision: Collision handling for bounding boxes and a tile map.
- Host: GitHub
- URL: https://github.com/hackergrrl/collide-2d-aabb-tilemap
- Owner: hackergrrl
- Created: 2015-11-19T04:36:32.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2015-11-19T04:37:53.000Z (over 9 years ago)
- Last Synced: 2024-12-28T21:44:09.305Z (7 months ago)
- Language: JavaScript
- Homepage:
- Size: 5.86 KB
- Stars: 6
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# collide-2d-aabb-tilemap
> Determines whether a moving axis-aligned bounding box collides with a tilemap, and prevents intersection.
Based off
[collide-2d-tilemap](https://github.com/chrisdickinson/collide-2d-tilemap).
The key difference is that this module provides a non-destructive API, and
doesn't depend on [aabb-2d](https://github.com/chrisdickinson/aabb-2d).
## Example
[Here's a playable demo.](http://didact.us/collide-2d-tilemap/)
Example usage:
```javascript
var collideAabbTilemap = require('collide-2d-aabb-tilemap')
var tilemap = [
[ 0, 0, 0, 1 ],
[ 1, 0, 0, 1 ],
[ 1, 0, 0, 1 ],
[ 1, 1, 1, 1 ]
]
// (0,0) - (16,16)
var player = [0, 0, 16, 16]
// collideAabbTilemap(field, size of tile in pixels, [width, height])
collide = collideAabbTilemap(my_tilemap, 32, [4, 4])
my_game_event_loop(function(dt) {
var vec = get_player_input() * dt
collide(player, vec, function(moveAxis, moveDir, tileIdx, tileCoords) {
// true => solid
return tileIdx > 0
})
})
```
The algorithm used is taken from [this
article](http://higherorderfun.com/blog/2012/05/20/the-guide-to-implementing-2d-platformers/).
Detection and correction is applied on each X and Y axis separately.
## Usage
### var collide = collideAabbTilemap(array, tilesize[, dimensions])
Produces a `collide(aabb, vec2, oncollide)` function.
`array` may be a single-dimension array (or
[ndarray](https://www.npmjs.com/package/ndarray)) of integers **OR** a function
of the form `fn(tileX, tileY) -> integer`.
`tilesize` are the pixel dimensions of a tile.
`dimensions` is a size 2 array of integers, `[width, height]`. If it is not
provided, the map will be assumed to be square.
### var offset = collide(aabb, moveDelta, onCollide)
Attempt to advance `aabb` by `moveDelta` against the aforementioned `tilemap`.
Non-destructive.
If there is no collision, `offset == moveDelta`. Otherwise, it will be shorter
in one or both axes.
`aabb` is assumed to be a size 4 array of the form `[x, y, width, height]`.
`moveDelta` is assumed to be a `gl-matrix`-style `vec2` or `[x, y]`.
`onCollide` is a callback function, taking the following arguments:
* `moveAxis`: an integer representing the axis of movement. `0` (X) or `1` (Y).
* `moveDir`: either -1 or 1, denoting the direction of the movement.
* `tileIdx`: the tile integer data of the tile a candidate collision has been detected against.
* `tileCoords`: a size 2 array of tile coordinates.
If the callback returns a truthy value, the tile will be treated as solid, and
no further tiles will be checked along this axis.
## License
MIT