ngraph.forcelayout3d/lib/dragForce.js

Force directed graph layout in 3d

/**
 * Represents 3d drag force, which reduces force value on each step by given
 * coefficient.
 *
 * @param {Object} options for the drag force
 * @param {Number=} options.dragCoeff drag force coefficient. 0.1 by default
 */
module.exports = function (options) {
  var merge = require('ngraph.merge'),
      expose = require('ngraph.expose');

  options = merge(options, {
    dragCoeff: 0.02
  });

  var api = {
    update : function (body) {
      body.force.x -= options.dragCoeff * body.velocity.x;
      body.force.y -= options.dragCoeff * body.velocity.y;
      body.force.z -= options.dragCoeff * body.velocity.z;
    }
  };

  // let easy access to dragCoeff:
  expose(options, api, ['dragCoeff']);

  return api;
};