import PhysicsBase from './PhysicsBase';
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class PhysicsWorker extends PhysicsBase {
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constructor(postMessage) {
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super();
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this.body = {
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nodes: {},
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edges: {}
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};
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this.postMessage = postMessage;
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this.previousStates = {};
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this.toRemove = {
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nodeIds: [],
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edgeIds: []
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};
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this.physicsTimeout = null;
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this.isWorker = true;
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this.emit = (event, data) => {this.postMessage({type: 'emit', data: {event: event, data: data}})};
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}
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handleMessage(event) {
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var msg = event.data;
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switch (msg.type) {
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case 'physicsTick':
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this.processRemovals();
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this.physicsTick();
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this.sendPositions();
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break;
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case 'updatePositions':
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this.receivePositions(msg.data);
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break;
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case 'updateProperties':
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this.updateProperties(msg.data);
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break;
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case 'addElements':
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this.addElements(msg.data);
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break;
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case 'removeElements':
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this.removeElements(msg.data);
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break;
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case 'stabilize':
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this.stabilize(msg.data);
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break;
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case 'setStabilized':
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this.stabilized = msg.data;
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break;
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case 'initPhysicsData':
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console.debug('init physics data');
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this.initPhysicsData(msg.data);
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break;
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case 'options':
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this.options = msg.data;
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this.timestep = this.options.timestep;
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this.initPhysicsSolvers();
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break;
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default:
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console.warn('unknown message from PhysicsEngine', msg);
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}
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}
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sendPositions() {
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let nodeIndices = this.physicsBody.physicsNodeIndices;
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let positions = {};
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for (let i = 0; i < nodeIndices.length; i++) {
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let nodeId = nodeIndices[i];
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let node = this.body.nodes[nodeId];
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positions[nodeId] = {x:node.x, y:node.y};
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}
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this.postMessage({
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type: 'positions',
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data: {
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positions: positions,
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stabilized: this.stabilized
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}
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});
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}
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receivePositions(data) {
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let updatedNode = this.body.nodes[data.id];
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if (updatedNode) {
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updatedNode.x = data.x;
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updatedNode.y = data.y;
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this.physicsBody.forces[updatedNode.id] = {x: 0, y: 0};
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this.physicsBody.velocities[updatedNode.id] = {x: 0, y: 0};
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}
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}
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stabilize(data) {
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this.stabilized = false;
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this.targetIterations = data.targetIterations;
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this.stabilizationIterations = 0;
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setTimeout(() => this._stabilizationBatch(), 0);
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}
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updateProperties(data) {
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if (data.type === 'node') {
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let optionsNode = this.body.nodes[data.id];
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if (optionsNode) {
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let opts = data.options;
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if (opts.fixed) {
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if (opts.fixed.x !== undefined) {
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optionsNode.options.fixed.x = opts.fixed.x;
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}
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if (opts.fixed.y !== undefined) {
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optionsNode.options.fixed.y = opts.fixed.y;
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}
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}
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if (opts.mass !== undefined) {
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optionsNode.options.mass = opts.mass;
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}
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if (opts.edges && opts.edges.length) {
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optionsNode.edges.length = opts.edges.length;
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}
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} else {
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console.warn('sending properties to unknown node', data.id, data.options);
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}
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} else if (data.type === 'edge') {
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let edge = this.body.edges[data.id];
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if (edge) {
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let opts = data.options;
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if (opts.connected) {
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edge.connected = opts.connected;
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}
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} else {
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console.warn('sending properties to unknown edge', data.id, data.options);
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}
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} else {
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console.warn('sending properties to unknown element', data.id, data.options);
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}
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}
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addElements(data, replaceElements = true) {
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let nodeIds = Object.keys(data.nodes);
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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 newNode = data.nodes[nodeId];
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if (replaceElements) {
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this.body.nodes[nodeId] = newNode;
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}
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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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if (this.physicsBody.physicsNodeIndices.indexOf(nodeId) === -1) {
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this.physicsBody.physicsNodeIndices.push(nodeId);
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}
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}
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let edgeIds = Object.keys(data.edges);
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for (let i = 0; i < edgeIds.length; i++) {
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let edgeId = edgeIds[i];
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if (replaceElements) {
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this.body.edges[edgeId] = data.edges[edgeId];
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}
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if (this.physicsBody.physicsEdgeIndices.indexOf(edgeId) === -1) {
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this.physicsBody.physicsEdgeIndices.push(edgeId);
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}
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}
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}
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removeElements(data) {
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// schedule removal of elements on the next physicsTick
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// avoids having to defensively check every node read in each physics implementation
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this.toRemove.nodeIds.push.apply(this.toRemove.nodeIds, data.nodeIds);
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this.toRemove.edgeIds.push.apply(this.toRemove.edgeIds, data.edgeIds);
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// Handle case where physics is disabled.
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if (!this.options.enabled) {
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this.processRemovals();
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}
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}
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processRemovals() {
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while (this.toRemove.nodeIds.length > 0) {
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let nodeId = this.toRemove.nodeIds.pop();
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let index = this.physicsBody.physicsNodeIndices.indexOf(nodeId);
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if (index > -1) {
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this.physicsBody.physicsNodeIndices.splice(index,1);
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}
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delete this.physicsBody.forces[nodeId];
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delete this.physicsBody.velocities[nodeId];
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delete this.body.nodes[nodeId];
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}
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while (this.toRemove.edgeIds.length > 0) {
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let edgeId = this.toRemove.edgeIds.pop();
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let index = this.physicsBody.physicsEdgeIndices.indexOf(edgeId);
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if (index > -1) {
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this.physicsBody.physicsEdgeIndices.splice(index,1);
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}
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delete this.body.edges[edgeId];
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}
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}
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initPhysicsData(data) {
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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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this.body.nodes = data.nodes;
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this.body.edges = data.edges;
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this.addElements(data, false);
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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 (this.body.nodes[nodeId] === undefined) {
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delete this.physicsBody.velocities[nodeId];
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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.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.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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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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_finalizeStabilization() {
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this.sendPositions();
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this.postMessage({
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type: 'finalizeStabilization',
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data: {
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stabilizationIterations: this.stabilizationIterations
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}
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});
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}
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}
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export default PhysicsWorker;
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