@c-frame/aframe-physics-system/src/components/math/velocity.js

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

/**
 * Velocity, in m/s.
 */
module.exports = AFRAME.registerComponent('velocity', {
  schema: {type: 'vec3'},

  init: function () {
    this.system = this.el.sceneEl.systems.physics;

    if (this.system) {
      this.system.addComponent(this);
    }
  },

  remove: function () {
    if (this.system) {
      this.system.removeComponent(this);
    }
  },

  tick: function (t, dt) {
    if (!dt) return;
    if (this.system) return;
    this.afterStep(t, dt);
  },

  afterStep: function (t, dt) {
    if (!dt) return;

    var physics = this.el.sceneEl.systems.physics || {data: {maxInterval: 1 / 60}},

    // TODO - There's definitely a bug with getComputedAttribute and el.data.
    velocity = this.el.getAttribute('velocity') || {x: 0, y: 0, z: 0},
    position = this.el.object3D.position || {x: 0, y: 0, z: 0};

    dt = Math.min(dt, physics.data.maxInterval * 1000);

    this.el.object3D.position.set(
      position.x + velocity.x * dt / 1000,
      position.y + velocity.y * dt / 1000,
      position.z + velocity.z * dt / 1000
    );
  }
});