detect collisions 2d between all possible kinds of shapes. It uses Bounding Volume Hierarchy (BVH) for sweep wide quick tree trim phase, and the Separating Axis Theorem (SAT) for accurate detection inside nearby groups. This library supports RayCasting, o
npm install check2dcheck2d is a feature-complete 2D collision detection library for JavaScript, designed for real-time games and simulations.
It combines a Bounding Volume Hierarchy (BVH) broad phase with Separating Axis Theorem (SAT) narrow phase detection, providing fast and accurate collision checks across many shape types.
- BVH-based broad phase for high performance
- SAT-based precise collision detection
- supports boxes, circles, ellipses, polygons, lines, points
- raycasting, offsets, rotation, scaling
- group-based collision filtering
- visual debugging helpers
- browser and Node.js support
- battle-tested and well benchmarked
---
- Stress test
https://nenjack.github.io/check2d/demo/?stress
- Tank demo
https://nenjack.github.io/check2d/demo/
- StackBlitz
https://stackblitz.com/edit/check2d
- CodePan
https://nenjack.github.io/codepan/#/boilerplate/check2d?pans=console,html
---
``ts
const { System } = require('check2d')
const system = new System()
``
`ts
const { Box, Circle, Polygon } = require('check2d')
const box = system.createBox({ x: 0, y: 0 }, 10, 10)
const circle = new Circle({ x: 5, y: 0 }, 5)
system.insert(circle)
`
---
Bodies can be transformed freely. Changes are batched and applied once.
`ts
box.setPosition(10, 5, false)
box.setAngle(Math.PI / 4, false)
box.setScale(2, 1, false)
box.move(1, false)
box.updateBody()
`
Supported features include:
* position, rotation, scale
* movement in facing direction
* offsets relative to body center
* AABB access
* padding to reduce BVH reinserts
* group-based collision filtering
---
`ts
system.checkAll((result) => {
console.log(result)
})
system.checkOne(box, (result) => {
console.log(result)
})
// optional automatic separation
system.separate()
`
`ts`
const points = system.getCollisionPoints(result.a, result.b)
---
`ts
const hit = system.raycast(
{ x: 0, y: 0 },
{ x: 0, y: -10 },
(body) => true
)
if (hit) {
const { point, body } = hit
console.log(point, body)
}
`
---
Draw bodies directly to a
`ts`
context.beginPath()
system.draw(context)
context.stroke()
Draw BVH bounding boxes:
`ts`
context.beginPath()
system.drawBVH(context)
context.stroke()
---
`js`
import { System } from 'https://esm.sh/check2d'
---
`bash`
Test Suites: 12 passed, 12 total
Tests: 84 passed, 84 total
Run benchmarks and stress tests:
`bash`
git clone https://github.com/nenjack/check2d.git
cd check2d
npm i
npm run benchmark
---
`bash`
yarn add check2d
---
API reference and guides:
https://nenjack.github.io/check2d/
---
Physics engines like Matter.js or Planck.js are excellent when full simulation is required, but they often introduce unnecessary overhead when only collision detection is needed.
check2d focuses purely on collision detection:
* no gravity
* no forces
* no assumptions about movement
This makes it ideal as a standalone collision system or as the foundation of a custom physics engine.
---
Contributions are welcome.
* run npm run precommitany`
* follow conventional commits
* avoid using
---
MIT