import PhysicsBase from './PhysicsBase';
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import PhysicsWorker from 'worker!./PhysicsWorkerWrapper';
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var util = require('../../util');
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class PhysicsEngine extends PhysicsBase {
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constructor(body) {
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super();
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this.body = body;
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this.physicsEnabled = true;
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this.simulationInterval = 1000 / 60;
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this.requiresTimeout = true;
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this.freezeCache = {};
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this.renderTimer = undefined;
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this.ready = false; // will be set to true if the stabilize
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// default options
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this.defaultOptions = {
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enabled: true,
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useWorker: false,
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barnesHut: {
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theta: 0.5,
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gravitationalConstant: -2000,
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centralGravity: 0.3,
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springLength: 95,
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springConstant: 0.04,
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damping: 0.09,
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avoidOverlap: 0
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},
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forceAtlas2Based: {
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theta: 0.5,
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gravitationalConstant: -50,
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centralGravity: 0.01,
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springConstant: 0.08,
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springLength: 100,
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damping: 0.4,
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avoidOverlap: 0
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},
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repulsion: {
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centralGravity: 0.2,
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springLength: 200,
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springConstant: 0.05,
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nodeDistance: 100,
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damping: 0.09,
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avoidOverlap: 0
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},
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hierarchicalRepulsion: {
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centralGravity: 0.0,
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springLength: 100,
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springConstant: 0.01,
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nodeDistance: 120,
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damping: 0.09
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},
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maxVelocity: 50,
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minVelocity: 0.75, // px/s
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solver: 'barnesHut',
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stabilization: {
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enabled: true,
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iterations: 1000, // maximum number of iteration to stabilize
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updateInterval: 50,
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onlyDynamicEdges: false,
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fit: true
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},
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timestep: 0.5,
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adaptiveTimestep: true
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};
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util.extend(this.options, this.defaultOptions);
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this.layoutFailed = false;
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this.draggingNodes = [];
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this.positionUpdateHandler = () => {};
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this.physicsUpdateHandler = () => {};
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this.emit = this.body.emitter.emit;
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this.bindEventListeners();
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}
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bindEventListeners() {
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this.body.emitter.on('initPhysics', () => {this.initPhysics();});
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this.body.emitter.on('_layoutFailed', () => {this.layoutFailed = true;});
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this.body.emitter.on('resetPhysics', () => {this.stopSimulation(); this.ready = false;});
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this.body.emitter.on('disablePhysics', () => {this.physicsEnabled = false; this.stopSimulation();});
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this.body.emitter.on('restorePhysics', () => {
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this.setOptions(this.options);
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if (this.ready === true) {
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this.startSimulation();
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}
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});
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this.body.emitter.on('startSimulation', () => {
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if (this.ready === true) {
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this.startSimulation();
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}
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});
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this.body.emitter.on('stopSimulation', () => {this.stopSimulation();});
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this.body.emitter.on('destroy', () => {
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this.stopSimulation(false);
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this.body.emitter.off();
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});
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this.body.emitter.on('_positionUpdate', (properties) => this.positionUpdateHandler(properties));
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this.body.emitter.on('_physicsUpdate', (properties) => this.physicsUpdateHandler(properties));
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this.body.emitter.on('dragStart', (properties) => {
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this.draggingNodes = properties.nodes;
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});
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this.body.emitter.on('dragEnd', () => {
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this.draggingNodes = [];
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});
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this.body.emitter.on('destroy', () => {
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if (this.physicsWorker) {
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this.physicsWorker.terminate();
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this.physicsWorker = undefined;
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}
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});
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}
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/**
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* set the physics options
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* @param options
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*/
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setOptions(options) {
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if (options !== undefined) {
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if (options === false) {
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this.options.enabled = false;
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this.physicsEnabled = false;
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this.stopSimulation();
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}
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else {
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this.physicsEnabled = true;
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util.selectiveNotDeepExtend(['stabilization'], this.options, options);
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util.mergeOptions(this.options, options, 'stabilization')
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if (options.enabled === undefined) {
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this.options.enabled = true;
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}
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if (this.options.enabled === false) {
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this.physicsEnabled = false;
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this.stopSimulation();
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}
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// set the timestep
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this.timestep = this.options.timestep;
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}
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}
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if (this.options.useWorker) {
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this.initPhysicsWorker();
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this.physicsWorker.postMessage({type: 'options', data: this.options});
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} else {
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this.initEmbeddedPhysics();
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}
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}
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/**
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* configure the engine.
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*/
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initEmbeddedPhysics() {
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this.positionUpdateHandler = () => {};
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this.physicsUpdateHandler = () => {};
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if (this.physicsWorker) {
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this.options.useWorker = false;
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this.physicsWorker.terminate();
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this.physicsWorker = undefined;
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this.initPhysicsData();
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}
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this.initPhysicsSolvers();
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}
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initPhysicsWorker() {
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if (!this.physicsWorker) {
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// setup path to webworker javascript file
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if (!__webpack_public_path__) {
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let parentScript = document.getElementById('visjs');
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if (parentScript) {
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let src = parentScript.getAttribute('src')
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__webpack_public_path__ = src.substr(0, src.lastIndexOf('/') + 1);
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} else {
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let scripts = document.getElementsByTagName('script');
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for (let i = 0; i < scripts.length; i++) {
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let src = scripts[i].getAttribute('src');
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if (src && src.length >= 6) {
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let position = src.length - 6;
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let index = src.indexOf('vis.js', position);
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if (index === position) {
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__webpack_public_path__ = src.substr(0, src.lastIndexOf('/') + 1);
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break;
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}
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}
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}
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}
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}
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// launch webworker
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this.physicsWorker = new PhysicsWorker();
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this.physicsWorker.addEventListener('message', (event) => {
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this.physicsWorkerMessageHandler(event);
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});
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this.physicsWorker.onerror = (event) => {
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console.error('Falling back to embedded physics engine', event);
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this.initEmbeddedPhysics();
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// throw new Error(event.message + " (" + event.filename + ":" + event.lineno + ")");
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};
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this.positionUpdateHandler = (positions) => {
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this.physicsWorker.postMessage({type: 'updatePositions', data: positions});
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};
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this.physicsUpdateHandler = (properties) => {
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this._physicsUpdateHandler(properties);
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};
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}
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}
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_physicsUpdateHandler(properties) {
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if (properties.options.physics !== undefined) {
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if (properties.options.physics) {
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let data = {
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nodes: {},
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edges: {}
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};
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if (properties.type === 'node') {
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data.nodes[properties.id] = this.createPhysicsNode(properties.id);
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} else if (properties.type === 'edge') {
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data.edges[properties.id] = this.createPhysicsEdge(properties.id);
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} else {
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console.warn('invalid element type');
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}
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this.physicsWorker.postMessage({
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type: 'addElements',
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data: data
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});
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} else {
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let data = {
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nodeIds: [],
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edgeIds: []
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};
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if (properties.type === 'node') {
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data.nodeIds = [properties.id.toString()];
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} else if (properties.type === 'edge') {
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data.edgeIds = [properties.id.toString()];
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} else {
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console.warn('invalid element type');
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}
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this.physicsWorker.postMessage({type: 'removeElements', data: data});
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}
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} else {
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this.physicsWorker.postMessage({type: 'updateProperties', data: properties});
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}
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}
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physicsWorkerMessageHandler(event) {
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var msg = event.data;
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switch (msg.type) {
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case 'positions':
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this.stabilized = msg.data.stabilized;
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this._receivedPositions(msg.data.positions);
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break;
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case 'finalizeStabilization':
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this.stabilizationIterations = msg.data.stabilizationIterations;
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this._finalizeStabilization();
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break;
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case 'emit':
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this.emit(msg.data.event, msg.data.data);
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break;
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default:
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console.warn('unhandled physics worker message:', msg);
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}
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}
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_receivedPositions(positions) {
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for (let i = 0; i < this.draggingNodes.length; i++) {
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delete positions[this.draggingNodes[i]];
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}
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let nodeIds = Object.keys(positions);
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for (let i = 0; i < nodeIds.length; i++) {
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let nodeId = nodeIds[i];
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let node = this.body.nodes[nodeId];
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// handle case where we get a positions from an old physicsObject
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if (node) {
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node.setX(positions[nodeId].x);
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node.setY(positions[nodeId].y);
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}
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}
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}
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/**
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* initialize the engine
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*/
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initPhysics() {
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if (this.physicsEnabled === true && this.options.enabled === true) {
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if (this.options.stabilization.enabled === true) {
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this.stabilize();
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}
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else {
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this.stabilized = false;
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this.ready = true;
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this.body.emitter.emit('fit', {}, this.layoutFailed); // if the layout failed, we use the approximation for the zoom
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this.startSimulation();
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}
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}
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else {
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this.ready = true;
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this.body.emitter.emit('fit');
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}
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}
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/**
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* Start the simulation
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*/
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startSimulation() {
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if (this.physicsEnabled === true && this.options.enabled === true) {
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this.stabilized = false;
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this._updateWorkerStabilized();
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// when visible, adaptivity is disabled.
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this.adaptiveTimestep = false;
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// this sets the width of all nodes initially which could be required for the avoidOverlap
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this.body.emitter.emit("_resizeNodes");
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if (this.viewFunction === undefined) {
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this.viewFunction = this.simulationStep.bind(this);
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this.body.emitter.on('initRedraw', this.viewFunction);
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this.body.emitter.emit('_startRendering');
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}
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}
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else {
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this.body.emitter.emit('_redraw');
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}
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}
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/**
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* Stop the simulation, force stabilization.
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*/
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stopSimulation(emit = true) {
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this.stabilized = true;
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this._updateWorkerStabilized();
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if (emit === true) {
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this._emitStabilized();
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}
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if (this.viewFunction !== undefined) {
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this.body.emitter.off('initRedraw', this.viewFunction);
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this.viewFunction = undefined;
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if (emit === true) {
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this.body.emitter.emit('_stopRendering');
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}
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}
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}
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_updateWorkerStabilized() {
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if (this.physicsWorker) {
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this.physicsWorker.postMessage({
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type: 'setStabilized',
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data: this.stabilized
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});
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}
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}
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/**
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* The viewFunction inserts this step into each renderloop. It calls the physics tick and handles the cleanup at stabilized.
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*
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*/
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simulationStep() {
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if (this.physicsWorker) {
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this.physicsWorker.postMessage({type: 'physicsTick'});
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} else {
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// check if the physics have settled
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var startTime = Date.now();
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this.physicsTick();
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var physicsTime = Date.now() - startTime;
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// run double speed if it is a little graph
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if ((physicsTime < 0.4 * this.simulationInterval || this.runDoubleSpeed === true) && this.stabilized === false) {
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this.physicsTick();
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// this makes sure there is no jitter. The decision is taken once to run it at double speed.
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this.runDoubleSpeed = true;
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}
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}
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if (this.stabilized === true) {
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this.stopSimulation();
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}
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}
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// TODO determine when startedStabilization needs to be propogated from the worker
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/**
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* trigger the stabilized event.
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* @private
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*/
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_emitStabilized(amountOfIterations = this.stabilizationIterations) {
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if (this.stabilizationIterations > 1 || this.startedStabilization === true) {
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setTimeout(() => {
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this.body.emitter.emit('stabilized', {iterations: amountOfIterations});
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this.startedStabilization = false;
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this.stabilizationIterations = 0;
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}, 0);
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}
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}
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createPhysicsNode(nodeId) {
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let node = this.body.nodes[nodeId];
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if (node) {
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return {
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id: node.id.toString(),
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x: node.x,
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y: node.y,
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// TODO update on change
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edges: {
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length: node.edges.length
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},
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options: {
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fixed: {
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x: node.options.fixed.x,
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y: node.options.fixed.y
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},
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mass: node.options.mass
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}
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}
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}
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}
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createPhysicsEdge(edgeId) {
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let edge = this.body.edges[edgeId];
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if (edge && edge.options.physics === true) {
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let physicsEdge = {
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id: edge.id,
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connected: edge.connected,
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edgeType: {},
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toId: edge.toId,
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fromId: edge.fromId,
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options: {
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length: edge.length
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}
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};
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// TODO test/implment dynamic
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if (edge.edgeType.via) {
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physicsEdge.edgeType = {
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via: {
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id: edge.edgeType.via.id
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}
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}
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}
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return physicsEdge;
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}
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}
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/**
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* Nodes and edges can have the physics toggles on or off. A collection of indices is created here so we can skip the check all the time.
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*
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* @private
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*/
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initPhysicsData() {
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let nodes = this.body.nodes;
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let edges = this.body.edges;
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this.physicsBody.forces = {};
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this.physicsBody.physicsNodeIndices = [];
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this.physicsBody.physicsEdgeIndices = [];
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let physicsWorkerNodes = {};
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let physicsWorkerEdges = {};
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// get node indices for physics
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for (let nodeId in nodes) {
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if (nodes.hasOwnProperty(nodeId)) {
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if (nodes[nodeId].options.physics === true) {
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this.physicsBody.physicsNodeIndices.push(nodeId);
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if (this.physicsWorker) {
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physicsWorkerNodes[nodeId] = this.createPhysicsNode(nodeId);
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}
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}
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}
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}
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// get edge indices for physics
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for (let edgeId in edges) {
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if (edges.hasOwnProperty(edgeId)) {
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if (edges[edgeId].options.physics === true) {
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this.physicsBody.physicsEdgeIndices.push(edgeId);
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if (this.physicsWorker) {
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physicsWorkerEdges[edgeId] = this.createPhysicsEdge(edgeId);
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}
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}
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}
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}
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// get the velocity and the forces vector
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for (let i = 0; i < this.physicsBody.physicsNodeIndices.length; i++) {
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let nodeId = this.physicsBody.physicsNodeIndices[i];
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this.physicsBody.forces[nodeId] = {x: 0, y: 0};
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// forces can be reset because they are recalculated. Velocities have to persist.
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if (this.physicsBody.velocities[nodeId] === undefined) {
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this.physicsBody.velocities[nodeId] = {x: 0, y: 0};
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}
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}
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// clean deleted nodes from the velocity vector
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for (let nodeId in this.physicsBody.velocities) {
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if (nodes[nodeId] === undefined) {
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delete this.physicsBody.velocities[nodeId];
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}
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}
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if (this.physicsWorker) {
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this.physicsWorker.postMessage({
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type: 'initPhysicsData',
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data: {
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nodes: physicsWorkerNodes,
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edges: physicsWorkerEdges
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}
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});
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}
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}
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|
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/**
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* Perform the actual step
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*
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* @param nodeId
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* @param maxVelocity
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* @returns {number}
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* @private
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*/
|
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_performStep(nodeId,maxVelocity) {
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let node = this.body.nodes[nodeId];
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let timestep = this.timestep;
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let forces = this.physicsBody.forces;
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let velocities = this.physicsBody.velocities;
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// store the state so we can revert
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this.previousStates[nodeId] = {x:node.x, y:node.y, vx:velocities[nodeId].x, vy:velocities[nodeId].y};
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if (node.options.fixed.x === false) {
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let dx = this.modelOptions.damping * velocities[nodeId].x; // damping force
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let ax = (forces[nodeId].x - dx) / node.options.mass; // acceleration
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velocities[nodeId].x += ax * timestep; // velocity
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velocities[nodeId].x = (Math.abs(velocities[nodeId].x) > maxVelocity) ? ((velocities[nodeId].x > 0) ? maxVelocity : -maxVelocity) : velocities[nodeId].x;
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node.setX(node.x + velocities[nodeId].x * timestep); // position
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}
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else {
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forces[nodeId].x = 0;
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velocities[nodeId].x = 0;
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}
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if (node.options.fixed.y === false) {
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let dy = this.modelOptions.damping * velocities[nodeId].y; // damping force
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let ay = (forces[nodeId].y - dy) / node.options.mass; // acceleration
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velocities[nodeId].y += ay * timestep; // velocity
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velocities[nodeId].y = (Math.abs(velocities[nodeId].y) > maxVelocity) ? ((velocities[nodeId].y > 0) ? maxVelocity : -maxVelocity) : velocities[nodeId].y;
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node.setY(node.y + velocities[nodeId].y * timestep); // position
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}
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else {
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forces[nodeId].y = 0;
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velocities[nodeId].y = 0;
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}
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|
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let totalVelocity = Math.sqrt(Math.pow(velocities[nodeId].x,2) + Math.pow(velocities[nodeId].y,2));
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return totalVelocity;
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|
}
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|
|
|
// TODO probably want to move freeze/restore to PhysicsBase and do in worker if running
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|
/**
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|
* When initializing and stabilizing, we can freeze nodes with a predefined position. This greatly speeds up stabilization
|
|
* because only the supportnodes for the smoothCurves have to settle.
|
|
*
|
|
* @private
|
|
*/
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|
_freezeNodes() {
|
|
var nodes = this.body.nodes;
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|
for (var id in nodes) {
|
|
if (nodes.hasOwnProperty(id)) {
|
|
if (nodes[id].x && nodes[id].y) {
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|
this.freezeCache[id] = {x:nodes[id].options.fixed.x,y:nodes[id].options.fixed.y};
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|
nodes[id].setFixed(true);
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|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Unfreezes the nodes that have been frozen by _freezeDefinedNodes.
|
|
*
|
|
* @private
|
|
*/
|
|
_restoreFrozenNodes() {
|
|
var nodes = this.body.nodes;
|
|
for (var id in nodes) {
|
|
if (nodes.hasOwnProperty(id)) {
|
|
if (this.freezeCache[id] !== undefined) {
|
|
nodes[id].setFixed({x: this.freezeCache[id].x, y: this.freezeCache[id].y});
|
|
}
|
|
}
|
|
}
|
|
this.freezeCache = {};
|
|
}
|
|
|
|
/**
|
|
* Find a stable position for all nodes
|
|
* @private
|
|
*/
|
|
stabilize(iterations = this.options.stabilization.iterations) {
|
|
if (typeof iterations !== 'number') {
|
|
console.log('The stabilize method needs a numeric amount of iterations. Switching to default: ', this.options.stabilization.iterations);
|
|
iterations = this.options.stabilization.iterations;
|
|
}
|
|
|
|
if (this.physicsBody.physicsNodeIndices.length === 0) {
|
|
this.ready = true;
|
|
return;
|
|
}
|
|
|
|
// enable adaptive timesteps
|
|
this.adaptiveTimestep = true && this.options.adaptiveTimestep;
|
|
|
|
// this sets the width of all nodes initially which could be required for the avoidOverlap
|
|
this.body.emitter.emit("_resizeNodes");
|
|
|
|
// stop the render loop
|
|
this.stopSimulation();
|
|
|
|
// set stabilize to false
|
|
this.stabilized = false;
|
|
|
|
// block redraw requests
|
|
this.body.emitter.emit('_blockRedraw');
|
|
this.targetIterations = iterations;
|
|
|
|
// start the stabilization
|
|
if (this.options.stabilization.onlyDynamicEdges === true) {
|
|
this._freezeNodes();
|
|
}
|
|
this.stabilizationIterations = 0;
|
|
|
|
if (this.physicsWorker) {
|
|
this.physicsWorker.postMessage({
|
|
type: 'stabilize',
|
|
data: {
|
|
targetIterations: iterations
|
|
}
|
|
});
|
|
} else {
|
|
setTimeout(() => this._stabilizationBatch(), 0);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Wrap up the stabilization, fit and emit the events.
|
|
* @private
|
|
*/
|
|
_finalizeStabilization() {
|
|
this.body.emitter.emit('_allowRedraw');
|
|
if (this.options.stabilization.fit === true) {
|
|
this.body.emitter.emit('fit');
|
|
}
|
|
|
|
if (this.options.stabilization.onlyDynamicEdges === true) {
|
|
this._restoreFrozenNodes();
|
|
}
|
|
|
|
this.body.emitter.emit('stabilizationIterationsDone');
|
|
this.body.emitter.emit('_requestRedraw');
|
|
|
|
if (this.stabilized === true) {
|
|
this._emitStabilized();
|
|
}
|
|
else {
|
|
this.startSimulation();
|
|
}
|
|
|
|
this.ready = true;
|
|
}
|
|
|
|
}
|
|
|
|
export default PhysicsEngine;
|