@c-frame/aframe-physics-system/src/drivers/worker.js

Physics system for A-Frame VR, built on Cannon.js & Ammo.js

var Event = require('./event'),
    LocalDriver = require('./local-driver'),
    AmmoDriver = require('./ammo-driver'),
    protocol = require('../utils/protocol');

var ID = protocol.ID;

module.exports = function (self) {
  var driver = null;
  var bodies = {};
  var constraints = {};
  var stepSize;

  self.addEventListener('message', function (event) {
    var data = event.data;

    switch (data.type) {
      // Lifecycle.
      case Event.INIT:
        driver = data.engine === 'cannon'
          ? new LocalDriver()
          : new AmmoDriver();
        driver.init(data.worldConfig);
        stepSize = 1 / data.fps;
        setInterval(step, 1000 / data.fps);
        break;

      // Bodies.
      case Event.ADD_BODY:
        var body = protocol.deserializeBody(data.body);
        body.material = driver.getMaterial( 'defaultMaterial' );
        bodies[body[ID]] = body;

        body.addEventListener('collide', function (evt) {
          var message = {
            type: Event.COLLIDE,
            bodyID: evt.target[ID], // set the target as the body to be identical to the local driver
            targetID: evt.body[ID], // set the body as the target to be identical to the local driver
            contact: protocol.serializeContact(evt.contact)
          }
          self.postMessage(message);
        });
        driver.addBody(body);
        break;
      case Event.REMOVE_BODY:
        driver.removeBody(bodies[data.bodyID]);
        delete bodies[data.bodyID];
        break;
      case Event.APPLY_BODY_METHOD:
        bodies[data.bodyID][data.methodName](
          protocol.deserializeVec3(data.args[0]),
          protocol.deserializeVec3(data.args[1])
        );
        break;
      case Event.UPDATE_BODY_PROPERTIES:
        protocol.deserializeBodyUpdate(data.body, bodies[data.body.id]);
        break;

      // Materials.
      case Event.ADD_MATERIAL:
        driver.addMaterial(data.materialConfig);
        break;
      case Event.ADD_CONTACT_MATERIAL:
        driver.addContactMaterial(
          data.materialName1,
          data.materialName2,
          data.contactMaterialConfig
        );
        break;

      // Constraints.
      case Event.ADD_CONSTRAINT:
        var constraint = protocol.deserializeConstraint(data.constraint, bodies);
        constraints[constraint[ID]] = constraint;
        driver.addConstraint(constraint);
        break;
      case Event.REMOVE_CONSTRAINT:
        driver.removeConstraint(constraints[data.constraintID]);
        delete constraints[data.constraintID];
        break;

      default:
        throw new Error('[Worker] Unexpected event type: %s', data.type);

    }
  });

  function step () {
    driver.step(stepSize);

    var bodyMessages = {};
    Object.keys(bodies).forEach(function (id) {
      bodyMessages[id] = protocol.serializeBody(bodies[id]);
    });

    self.postMessage({
      type: Event.STEP,
      bodies: bodyMessages,
      contacts: driver.getContacts().map(protocol.serializeContact)
    });
  }
};