PhysicsEngine.js

A lightweight JavaScript physics engine for both 2D and 3D, with built-in support for Three.js. Perfect for games, simulations, and interactive projects that need simple but robust physics without a heavy dependency.

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Features

• ✅ 2D & 3D physics support
• ✅ Three.js integration
• ✅ Simple gravity system
• ✅ Collision-ready object model
• ✅ Extendable physics properties
• ✅ No external physics libraries required

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Supported Physics Properties

Property	Description
mass	Weight of the object
gravity	Gravity strength applied
velocity	Current movement speed
acceleration	Change in velocity
friction	Resistance to motion
drag	Air resistance
bounce	Elasticity on collision
rotation	Spin (2D or 3D)
angularVelocity	Rotational speed
isStatic	If true, object does not move
useGravity	Toggle gravity per object

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Installation

No package manager required. Just include the script:

<script src="PhysicsEngine.js"></script>

Or, if you’re using modules:

import { PhysicsEngine } from "./PhysicsEngine.js";

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Basic Usage (2D)

const engine = new PhysicsEngine({
  dimension: "2D",
  gravity: 9.8
});

const box = engine.createObject({
  x: 100,
  y: 0,
  width: 50,
  height: 50,
  mass: 2,
  useGravity: true
});

engine.update(deltaTime);

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Three.js Usage (3D)

const engine = new PhysicsEngine({
  dimension: "3D",
  gravity: 9.81
});

const cube = new THREE.Mesh(
  new THREE.BoxGeometry(1,1,1),
  new THREE.MeshStandardMaterial()
);
scene.add(cube);

engine.attachThreeObject(cube, {
  mass: 1,
  useGravity: true,
  bounce: 0.6
});

The engine automatically syncs:

• Position
• Rotation
• Velocity

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Updating the Engine

Call this inside your animation loop:

function animate(time) {
  requestAnimationFrame(animate);
  const deltaTime = time - lastTime;
  lastTime = time;
  engine.update(deltaTime / 1000);
  renderer.render(scene, camera);
}

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Object API

object.applyForce({ x: 0, y: -10, z: 0 });
object.setVelocity({ x: 5, y: 0, z: 0 });
object.stop();

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Configuration Options

new PhysicsEngine({
  dimension: "3D",
  gravity: 9.81,
  maxVelocity: 100,
  globalFriction: 0.98
});

---

License

MIT (or specify your license here)

If you’re using modules:

import { PhysicsEngine } from "./PhysicsEngine.js";

Basic Usage (2D)

const engine = new PhysicsEngine({
  dimension: "2D",
  gravity: 9.8
});

const box = engine.createObject({
  x: 100,
  y: 0,
  width: 50,
  height: 50,
  mass: 2,
  useGravity: true
});

engine.update(deltaTime);

Three.js Usage (3D)
const engine = new PhysicsEngine({
  dimension: "3D",
  gravity: 9.81
});

const cube = new THREE.Mesh(
  new THREE.BoxGeometry(1,1,1),
  new THREE.MeshStandardMaterial()
);

scene.add(cube);

engine.attachThreeObject(cube, {
  mass: 1,
  useGravity: true,
  bounce: 0.6
});

The engine automatically syncs:

• Position

• Rotation

• Velocity

• Updating the Engine

Call this inside your animation loop:

function animate(time) {
  requestAnimationFrame(animate);

  const deltaTime = time - lastTime;
  lastTime = time;

  engine.update(deltaTime / 1000);
  renderer.render(scene, camera);
}

Object API

object.applyForce({ x: 0, y: -10, z: 0 });
object.setVelocity({ x: 5, y: 0, z: 0 });
object.stop();

Configuration Options

new PhysicsEngine({
  dimension: "3D",
  gravity: 9.81,
  maxVelocity: 100,
  globalFriction: 0.98
});