# erincatto/box2d-lite

A small 2D physics engine

Repository: https://github.com/erincatto/box2d-lite
Canonical: https://ross.abutalabs.com/products/box2d-lite
Homepage: http://box2d.org/
Language: C++
License: MIT
License Family: permissive
Last push: 2020-01-10T04:32:10+00:00

## Health v2 (maintenance only)
Score: 23/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 2800, "days_push": 2427, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1074, forks 138 (observed 2026-08-28T04:03:29.031176+00:00)

## What it is
Box2D-Lite is a small 2D rigid body physics engine written in C++, originally developed for the 2006 GDC Physics Tutorial. It is the minimal predecessor of the full Box2D library and is intended primarily for learning how game physics engines work.

## Use cases
- learn how 2D physics engines work internally
- simulate rigid bodies and collisions in a 2D game
- study sequential impulse solver techniques from the GDC tutorial
- prototype simple 2D physics interactions
- use as a teaching example for game physics courses

## When to choose
- you want a tiny, readable codebase to study physics engine internals
- you need basic 2D rigid body simulation with minimal dependencies
- you are teaching or learning game physics concepts

## When to avoid
- you need a production-grade physics engine with full features (use Box2D)
- you need 3D physics simulation
- you need active maintenance, documentation, or community support

## Facets
- artifact type: library
- maturity: maintenance
- function: simulation, graphics
- domain: simulation, education
- platform: cpp, cross-platform
- tags: 2d-physics, rigid-body, collision-detection, physics-engine, learning-resource, game-development

## Member repositories
- erincatto/box2d-lite (main) score 23

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:29.031176+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:53:30.780557+00:00, confidence not recorded.
  - readme: https://github.com/erincatto/box2d-lite (fetched 2026-08-28T04:03:29.031176+00:00, sha fc60b6a53866)
  - homepage: http://box2d.org/ (fetched 2026-08-29T12:55:11.041260+00:00, sha 1719829756c6)
  - site_page: https://box2d.org/about (fetched 2026-08-29T12:55:11.050409+00:00, sha 490da859b17e)
  - site_page: https://box2d.org/documentation (fetched 2026-08-29T12:55:11.052363+00:00, sha 89e27a64c1ea)
  - site_page: https://box2d.org/documentation3d (fetched 2026-08-29T12:55:11.054674+00:00, sha ed4bf1d107a8)
  - site_page: https://box2d.org/doc_version_2_4 (fetched 2026-08-29T12:55:11.056953+00:00, sha 161a23c6ded6)
- Data as of 2026-08-30T08:39:29.467469+00:00.