matterjs

Matter.js Skill

Workflow

1. Confirm environment (plain HTML, React, or canvas-only) and rendering approach (Matter.Render for debug vs custom renderer).
2. Provide a minimal Engine/World/Render/Runner setup and add bodies.
3. Add interactions (mouse constraint) or constraints only if requested.
4. Share cleanup steps for SPA or teardown scenarios.

Minimal setup

<script>
  const { Engine, Render, Runner, Bodies, Composite } = Matter;

  const engine = Engine.create();

const render = Render.create({ element: document.body, engine: engine, options: { width: 800, height: 600, wireframes: false } });

const runner = Runner.create(); Runner.run(runner, engine); Render.run(render);

const ground = Bodies.rectangle(400, 610, 810, 60, { isStatic: true }); const box = Bodies.rectangle(400, 200, 80, 80);

Composite.add(engine.world, [ground, box]);

## Common patterns
- Use `Composite.add(engine.world, [...])` to add bodies to the world.
- Use `Render.create({ element, engine })` to create a canvas automatically, or pass a `canvas` you create yourself.
- Set `render.options.wireframes = false` for solid rendering.
- Use `Runner.run(runner, engine)` for a simple loop, or call `Engine.update` in your own loop if you need custom timing.

## Mouse interaction (optional)
```js
const { Mouse, MouseConstraint } = Matter;
const mouse = Mouse.create(render.canvas);
const mouseConstraint = MouseConstraint.create(engine, { mouse });
Composite.add(engine.world, mouseConstraint);
render.mouse = mouse;

Cleanup checklist (SPA)

• Stop the runner with Runner.stop(runner).
• Remove the render canvas from the DOM.
• Clear engine and world if needed.

Questions to ask when specs are missing

• What viewport size and scaling should the canvas use?
• Are we using Matter.Render or a custom renderer?
• Do you want mouse/touch drag interaction?
• Should the simulation loop be paused when offscreen?