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192 lines
6.9 KiB
192 lines
6.9 KiB
/**
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* Created by Alex on 2/23/2015.
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*/
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import {BarnesHutSolver} from "./components/physics/BarnesHutSolver";
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import {Repulsion} from "./components/physics/RepulsionSolver";
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import {HierarchicalRepulsion} from "./components/physics/HierarchicalRepulsionSolver";
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import {SpringSolver} from "./components/physics/SpringSolver";
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import {HierarchicalSpringSolver} from "./components/physics/HierarchicalSpringSolver";
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import {CentralGravitySolver} from "./components/physics/CentralGravitySolver";
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class PhysicsEngine {
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constructor(body, options) {
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this.body = body;
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this.physicsBody = {calculationNodes: {}, calculationNodeIndices:[], forces: {}, velocities: {}};
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this.previousStates = {};
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this.setOptions(options);
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}
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setOptions(options) {
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if (options !== undefined) {
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this.options = options;
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this.init();
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}
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}
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init() {
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var options;
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if (this.options.model == "repulsion") {
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options = this.options.repulsion;
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this.nodesSolver = new Repulsion(this.body, this.physicsBody, options);
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this.edgesSolver = new SpringSolver(this.body, this.physicsBody, options);
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}
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else if (this.options.model == "hierarchicalRepulsion") {
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options = this.options.hierarchicalRepulsion;
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this.nodesSolver = new HierarchicalRepulsion(this.body, this.physicsBody, options);
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this.edgesSolver = new HierarchicalSpringSolver(this.body, this.physicsBody, options);
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}
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else { // barnesHut
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options = this.options.barnesHut;
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this.nodesSolver = new BarnesHutSolver(this.body, this.physicsBody, options);
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this.edgesSolver = new SpringSolver(this.body, this.physicsBody, options);
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}
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this.gravitySolver = new CentralGravitySolver(this.body, this.physicsBody, options);
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this.modelOptions = options;
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}
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/**
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* Smooth curves are created by adding invisible nodes in the center of the edges. These nodes are also
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* handled in the calculateForces function. We then use a quadratic curve with the center node as control.
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* This function joins the datanodes and invisible (called support) nodes into one object.
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* We do this so we do not contaminate this.body.nodes with the support nodes.
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*
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* @private
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*/
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_updateCalculationNodes() {
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this.physicsBody.calculationNodes = {};
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this.physicsBody.forces = {};
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this.physicsBody.calculationNodeIndices = [];
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for (let i = 0; i < this.body.nodeIndices.length; i++) {
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let nodeId = this.body.nodeIndices[i];
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this.physicsBody.calculationNodes[nodeId] = this.body.nodes[nodeId];
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}
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// if support nodes are used, we have them here
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var supportNodes = this.body.supportNodes;
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for (let i = 0; i < this.body.supportNodeIndices.length; i++) {
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let supportNodeId = this.body.supportNodeIndices[i];
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if (this.body.edges[supportNodes[supportNodeId].parentEdgeId] !== undefined) {
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this.physicsBody.calculationNodes[supportNodeId] = supportNodes[supportNodeId];
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}
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else {
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console.error("Support node detected that does not have an edge!")
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}
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}
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this.physicsBody.calculationNodeIndices = Object.keys(this.physicsBody.calculationNodes);
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for (let i = 0; i < this.physicsBody.calculationNodeIndices.length; i++) {
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let nodeId = this.physicsBody.calculationNodeIndices[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 (this.physicsBody.calculationNodes[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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revert() {
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var nodeIds = Object.keys(this.previousStates);
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var nodes = this.physicsBody.calculationNodes;
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var velocities = this.physicsBody.velocities;
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for (let i = 0; i < nodeIds.length; i++) {
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let nodeId = nodeIds[i];
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if (nodes[nodeId] !== undefined) {
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velocities[nodeId].x = this.previousStates[nodeId].vx;
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velocities[nodeId].y = this.previousStates[nodeId].vy;
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nodes[nodeId].x = this.previousStates[nodeId].x;
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nodes[nodeId].y = this.previousStates[nodeId].y;
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}
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else {
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delete this.previousStates[nodeId];
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}
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}
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}
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moveNodes() {
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var nodesPresent = false;
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var nodeIndices = this.physicsBody.calculationNodeIndices;
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var maxVelocity = this.options.maxVelocity === 0 ? 1e9 : this.options.maxVelocity;
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var moving = false;
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var vminCorrected = this.options.minVelocity / Math.max(this.body.functions.getScale(),0.05);
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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 nodeVelocity = this._performStep(nodeId, maxVelocity);
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moving = nodeVelocity > vminCorrected;
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nodesPresent = true;
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}
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if (nodesPresent == true) {
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if (vminCorrected > 0.5*this.options.maxVelocity) {
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return true;
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}
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else {
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return moving;
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}
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}
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return false;
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}
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_performStep(nodeId,maxVelocity) {
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var node = this.physicsBody.calculationNodes[nodeId];
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var timestep = this.options.timestep;
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var forces = this.physicsBody.forces;
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var 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.xFixed) {
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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.yFixed) {
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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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var 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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calculateForces() {
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this.gravitySolver.solve();
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this.nodesSolver.solve();
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this.edgesSolver.solve();
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}
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}
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export {PhysicsEngine};
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