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import BarnesHutSolver from "./BarnesHutSolver"
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/**
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* @class ForceAtlas2BasedRepulsionSolver
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* @extends BarnesHutSolver
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*/
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class ForceAtlas2BasedRepulsionSolver extends BarnesHutSolver {
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/**
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* @param {Object} body
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* @param {{physicsNodeIndices: Array, physicsEdgeIndices: Array, forces: {}, velocities: {}}} physicsBody
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* @param {Object} options
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* @constructor ForceAtlas2BasedRepulsionSolver
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* @extends BarnesHutSolver
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*/
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constructor(body, physicsBody, options) {
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super(body, physicsBody, options);
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}
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/**
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* Calculate the forces based on the distance.
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*
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* @param {number} distance
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* @param {number} dx
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* @param {number} dy
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* @param {vis.Node} node
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* @param {Object} parentBranch
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* @private
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*/
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_calculateForces(distance, dx, dy, node, parentBranch) {
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if (distance === 0) {
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distance = 0.1 * Math.random();
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dx = distance;
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}
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if (this.overlapAvoidanceFactor < 1 && node.shape.radius) {
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distance = Math.max(0.1 + (this.overlapAvoidanceFactor * node.shape.radius), distance - node.shape.radius);
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}
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let degree = (node.edges.length + 1);
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// the dividing by the distance cubed instead of squared allows us to get the fx and fy components without sines and cosines
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// it is shorthand for gravityforce with distance squared and fx = dx/distance * gravityForce
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let gravityForce = this.options.gravitationalConstant * parentBranch.mass * node.options.mass * degree / Math.pow(distance,2);
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let fx = dx * gravityForce;
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let fy = dy * gravityForce;
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this.physicsBody.forces[node.id].x += fx;
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this.physicsBody.forces[node.id].y += fy;
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}
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}
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export default ForceAtlas2BasedRepulsionSolver;
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