大炮 (Dàpào)

Lightweight 3D Physics for the Web and Beyond

Dapao is just a Typescript port of the cannon.js library with some added tests.

Project Goals

I am porting this to Typescript so I can use it within my own game engine (which is in Typescript). While the cannon.js version works perfectly well, I want to have better integration with my engine (tree shaking, etc), and I eventually want to be able to compile this to webassembly or maybe even native - things Javascript can't do at the moment.

Using the library

If you want to use the library, you can either reference this repo directly from within your webpack config:

...
"dependencies": {
  "dapao": "https://github.com/TheRohans/dapao.git#master",
  "document-register-element": "^1.7.0"
  ...
},
...

Or clone the repo and reference it from the local file system:

...
"dependencies": {
  "dapao": "file:../dapao",
  "document-register-element": "^1.7.0"
  ...
},
...

Contributing

Clone this repository
Install node.js
Run npm install to install all of the dependencies
Run npm run build to build DaPao

Example

For deeper examples, I recommend you checkout the cannon.js project (cannon.js), but here is a very basic example:

The sample code below creates a sphere on a plane, steps the simulation, and prints the sphere simulation to the console. Note that DaPao (and Cannon.js) uses SI units (metre, kilogram, second, etc.).

import * as DaPao from 'dapao';

// Setup our world
var world = new DaPao.World();
world.gravity.set(0, 0, -9.82); // m/s²

// Create a sphere
var radius = 1; // m
var sphereBody = new DaPao.Body({
   mass: 5, // kg
   position: new DaPao.Vec3(0, 0, 10), // m
   shape: new DaPao.Sphere(radius)
});
world.addBody(sphereBody);

// Create a plane
var groundBody = new DaPao.Body({
    mass: 0 // mass == 0 makes the body static
});
var groundShape = new DaPao.Plane();
groundBody.addShape(groundShape);
world.addBody(groundBody);

var fixedTimeStep = 1.0 / 60.0; // seconds
var maxSubSteps = 3;

// Start the simulation loop
var lastTime;
(function simloop(time){
  requestAnimationFrame(simloop);
  if(lastTime !== undefined){
     var dt = (time - lastTime) / 1000;
     world.step(fixedTimeStep, dt, maxSubSteps);
  }
  console.log("Sphere z position: " + sphereBody.position.z);
  lastTime = time;
})();

Features

Rigid body dynamics
Discrete collision detection
Contacts, friction and restitution
Collision filters
Body sleeping
Various shapes and collision algorithms (see table below)

	Sphere	Plane	Box	Convex	Particle	Heightfield	Trimesh
Sphere	Yes	Yes	Yes	Yes	NT	TD	TD
Plane	-	-	Yes	Yes	NT	-	TD
Box	-	-	Yes	BU	NT	TD	TD
Cylinder	-	-	NT	NT	NT	TD	TD
Convex	-	-	-	BU	NT	TD	TD
Particle	-	-	-	-	-	TD	TD
Heightfield	-	-	-	-	-	-	TD
Trimesh	-	-	-	-	-	-	-

NT = Not tested, but code exists. Feedback welcome.
BU = Buggy
TD = Todo