jpweeks/particulate-js

import { inherit } from '../utils/Creator'
import { Force } from './Force'

// ..................................................
// DirectionalForce
// ..................................................

export { DirectionalForce }

/**
  @module forces
*/

/**
  Defines a directional force that affects all particles in the system.

  ```javascript
  var gravity = DirectionalForce.create([0.0, -0.1, 0.0])
  ```

  @class DirectionalForce
  @extends Force
  @constructor
  @param {Array (Vec3)} vector  Direction vector
*/
function DirectionalForce(vector) {
  Force.call(this, vector)
}

/**
  Create instance, accepts constructor arguments.

  @method create
  @static
*/
inherit(DirectionalForce, Force)

DirectionalForce.prototype.applyForce = function (ix, f0, p0, p1) {
  var v0 = this.vector
  f0[ix]     += v0[0]
  f0[ix + 1] += v0[1]
  f0[ix + 2] += v0[2]
}