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https://github.com/andrewisen-tikab/three-spatial-hash-grid
A performant Spatial Hash Grid for three.js
https://github.com/andrewisen-tikab/three-spatial-hash-grid
spatial-hash-grid threejs
Last synced: about 1 month ago
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A performant Spatial Hash Grid for three.js
- Host: GitHub
- URL: https://github.com/andrewisen-tikab/three-spatial-hash-grid
- Owner: andrewisen-tikab
- License: mit
- Created: 2023-06-29T20:06:50.000Z (over 1 year ago)
- Default Branch: dev
- Last Pushed: 2024-04-04T07:39:00.000Z (8 months ago)
- Last Synced: 2024-04-04T08:39:16.248Z (8 months ago)
- Topics: spatial-hash-grid, threejs
- Language: TypeScript
- Homepage: https://andrewisen-tikab.github.io/three-spatial-hash-grid/example/
- Size: 8.23 MB
- Stars: 3
- Watchers: 1
- Forks: 0
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# three-spatial-hash-grid
`three-spacial-hash-grid` is a two-dimensional (!) spatial hash grid for [three.js](https://threejs.org/).
Heavily inspired by:
- ["Spatial Hash Grids & Tales from Game Development"](https://www.youtube.com/watch?v=sx4IIQL0x7c)
- ["How I Optimized My JavaScript Project (Complete Walkthrough) | Faster Spatial Hash Grids"](https://www.youtube.com/watch?v=oewDaISQpw0)
[](https://github.com/andrewisen-tikab/three-spatial-hash-grid/actions/workflows/pr.yml)
[](https://github.com/andrewisen-tikab/three-spatial-hash-grid/actions/workflows/release.yml)
## Example
[https://andrewisen-tikab.github.io/three-spatial-hash-grid/example/](https://andrewisen-tikab.github.io/three-spatial-hash-grid/example/)
## Usage
Setup at scene in three.js and add the grid to the scene.
```ts
import from 'three-spatial-hash-grid';
const grid = new (bounds, dimensions);
scene.add(spatialHashGrid.group);
```
## Config
> Bounds
The min/max the grid will operate on. I.e. if the world goes from `-1000, -1000` to `1000, 1000`, then this should be `[-1000, -1000], [1000, 1000]`.
> dimensions
How **many** cells along each dimensional axis. I.e. if the world is 100 units wide and we have 5 cells, then each cell will span `100/5=20 units`.
## Docs
Auto-generated docs can be found here:
[https://andrewisen-tikab.github.io/three-spatial-hash-grid/docs/](https://andrewisen-tikab.github.io/three-spatial-hash-grid/docs/)
## Remarks
Please note that this is a two-dimensional grid. +Y is up and Z is used for the depth of the grid.
See the example and look at the `axesHelper` for more information.
## Status
This is a work in progress. It is not yet ready for production.
## Spatial Hash Grid
A spatial hash is a 2 or 3 dimensional extension of the hash table.
The basic idea of a hash table is that you take a piece of data (the 'key'),
run it through some function (the 'hash function') to produce a new value (the 'hash'),
and then use the hash as an index into a set of slots ('cells').
Or, in other words:
You can define you 2D world into a fixed grid, e.g 4x4.
```
+---+---+---+---+
| a | b | c | d |
+---+---+---+---+
| e | f | g | h |
+---+---+---+---+
| i | j | k | l |
+---+---+---+---+
| m | n | o | p |
+---+---+---+---+
```
If you place an object into the world, it would fall into a least one of these cells.
For example, let's put an object `X` at cell `g`.
```
+---+---+---+---+
| a | b | c | d |
+---+---+---+---+
| e | f | X | h |
+---+---+---+---+
| i | j | k | l |
+---+---+---+---+
| m | n | o | p |
+---+---+---+---+
```
If we want to look for objects nearby, we simply check the nearby cells.
```
+---+---+---+---+
| | | c | |
+---+---+---+---+
| | f | X | h |
+---+---+---+---+
| | | k | |
+---+---+---+---+
| | | | |
+---+---+---+---+
```
In this example, we ignore the diagonally neighbors.
In other words: This is just like [Minesweeper]()
```
+---+---+---+---+
| ? | ? | ? | ? |
+---+---+---+---+
| ? | ? | X | ? |
+---+---+---+---+
| ? | ? | ? | ? |
+---+---+---+---+
| ? | ? | ? | ? |
+---+---+---+---+
```
See: [https://www.gamedev.net/tutorials/programming/general-and-gameplay-programming/spatial-hashing-r2697/](https://www.gamedev.net/tutorials/programming/general-and-gameplay-programming/spatial-hashing-r2697/)