https://github.com/hackergrrl/raycast-2d-tilemap

:white_square_button: Test a ray for intersections against a 2D tile map.
https://github.com/hackergrrl/raycast-2d-tilemap

Last synced: 1 day ago
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:white_square_button: Test a ray for intersections against a 2D tile map.

• Host: GitHub
• URL: https://github.com/hackergrrl/raycast-2d-tilemap
• Owner: hackergrrl
• License: mit
• Created: 2015-11-19T21:38:24.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2015-11-19T21:41:38.000Z (almost 9 years ago)
• Last Synced: 2024-09-16T11:47:24.342Z (17 days ago)
• Language: JavaScript
• Size: 2.93 KB
• Stars: 11
• Watchers: 3
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# raycast-2d-tilemap

> Test a ray for intersections against a 2D tile map.

## Background

This module is built atop the excellent

[fast-voxel-raycast](https://www.npmjs.com/package/fast-voxel-raycast) by Andy

Hall, which in turn is a fork of Mikola Lysenko's wonderful

[voxel-raycast](https://github.com/mikolalysenko/voxel-raycast).

Both are 3D voxel modules -- this module just wraps Andy's work to provide a

clean 2D interface.

## Installation

```sh

npm install raycast-2d-tilemap

```

## Example

```js

var raycast = require('raycast-2d-tilemap')

var tilemap = [

    [ 0, 0, 0, 1 ],

    [ 1, 0, 0, 1 ],

    [ 1, 0, 0, 1 ],

    [ 1, 1, 1, 1 ]

]

function getTileAt(x, y) {

  return tilemap[y][x]

}

var rayStart = [1, 0]

var rayDir = [0, 1]

var maxDistance = 100

var hitPos = new Array(2)

var hitNormal = new Array(2)

var tile = raycast(getTileAt, rayStart, rayDir, maxDistance, hitPos, hitNormal)

console.log(hitPos)

console.log(hitNormal)

```

outputs

```

[ 1, 3 ]

[ 0, -1 ]

```

## Usage

```js

var raycast = require('raycast-2d-tilemap')

```

### var tile = raycast(getTileAt, rayStart, rayDir, maxDistance, hitPos, hitNormal)

* `getTileAt` - a `function(x, y)` that returns a truthy value for whether a

  tile should block the ray's path

* `rayStart` - origin of the ray (vec2)

* `rayDirection` - direction of the ray (vec2)

* `maxDistance` - how far to check the ray before giving up

* `hitPosition` - result vec2 array; populated with the point of impact

* `hitNormal` - result vec2 array; populated with a normal vector pointing away

  from the tile that was struck 

**Returns:**  whatever value was returned by the `getTileAt` function for the

struck tile, or `0` if no tile was struck.