You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
435 lines
13 KiB
435 lines
13 KiB
/**
|
|
* Created by Alex on 2/23/2015.
|
|
*/
|
|
|
|
import {BarnesHutSolver} from "./components/physics/BarnesHutSolver";
|
|
import {Repulsion} from "./components/physics/RepulsionSolver";
|
|
import {HierarchicalRepulsion} from "./components/physics/HierarchicalRepulsionSolver";
|
|
import {SpringSolver} from "./components/physics/SpringSolver";
|
|
import {HierarchicalSpringSolver} from "./components/physics/HierarchicalSpringSolver";
|
|
import {CentralGravitySolver} from "./components/physics/CentralGravitySolver";
|
|
|
|
var util = require('../../util');
|
|
|
|
|
|
class PhysicsEngine {
|
|
constructor(body) {
|
|
this.body = body;
|
|
this.physicsBody = {physicsNodeIndices:[], physicsEdgeIndices:[], forces: {}, velocities: {}};
|
|
|
|
this.simulationInterval = 1000 / 60;
|
|
this.requiresTimeout = true;
|
|
this.previousStates = {};
|
|
this.renderTimer == undefined;
|
|
|
|
this.stabilized = false;
|
|
this.stabilizationIterations = 0;
|
|
this.ready = false; // will be set to true if the stabilize
|
|
|
|
// default options
|
|
this.options = {};
|
|
this.defaultOptions = {
|
|
barnesHut: {
|
|
thetaInverted: 1 / 0.5, // inverted to save time during calculation
|
|
gravitationalConstant: -2000,
|
|
centralGravity: 0.3,
|
|
springLength: 95,
|
|
springConstant: 0.04,
|
|
damping: 0.09
|
|
},
|
|
repulsion: {
|
|
centralGravity: 0.0,
|
|
springLength: 200,
|
|
springConstant: 0.05,
|
|
nodeDistance: 100,
|
|
damping: 0.09
|
|
},
|
|
hierarchicalRepulsion: {
|
|
centralGravity: 0.0,
|
|
springLength: 100,
|
|
springConstant: 0.01,
|
|
nodeDistance: 150,
|
|
damping: 0.09
|
|
},
|
|
solver: 'BarnesHut',
|
|
timestep: 0.5,
|
|
maxVelocity: 50,
|
|
minVelocity: 0.1, // px/s
|
|
stabilization: {
|
|
enabled: true,
|
|
iterations: 1000, // maximum number of iteration to stabilize
|
|
updateInterval: 100,
|
|
onlyDynamicEdges: false,
|
|
zoomExtent: true
|
|
}
|
|
}
|
|
util.extend(this.options, this.defaultOptions);
|
|
|
|
this.body.emitter.on("initPhysics", () => {this.initPhysics();});
|
|
this.body.emitter.on("resetPhysics", () => {this.stopSimulation(); this.ready = false;});
|
|
this.body.emitter.on("startSimulation", () => {
|
|
if (this.ready === true) {
|
|
this.stabilized = false;
|
|
this.runSimulation();
|
|
}
|
|
})
|
|
this.body.emitter.on("stopSimulation", () => {this.stopSimulation();});
|
|
}
|
|
|
|
setOptions(options) {
|
|
if (options !== undefined) {
|
|
util.selectiveNotDeepExtend(['stabilization'],this.options, options);
|
|
util.mergeOptions(this.options, options, 'stabilization')
|
|
}
|
|
this.init();
|
|
}
|
|
|
|
|
|
init() {
|
|
var options;
|
|
if (this.options.solver == "repulsion") {
|
|
options = this.options.repulsion;
|
|
this.nodesSolver = new Repulsion(this.body, this.physicsBody, options);
|
|
this.edgesSolver = new SpringSolver(this.body, this.physicsBody, options);
|
|
}
|
|
else if (this.options.solver == "hierarchicalRepulsion") {
|
|
options = this.options.hierarchicalRepulsion;
|
|
this.nodesSolver = new HierarchicalRepulsion(this.body, this.physicsBody, options);
|
|
this.edgesSolver = new HierarchicalSpringSolver(this.body, this.physicsBody, options);
|
|
}
|
|
else { // barnesHut
|
|
options = this.options.barnesHut;
|
|
this.nodesSolver = new BarnesHutSolver(this.body, this.physicsBody, options);
|
|
this.edgesSolver = new SpringSolver(this.body, this.physicsBody, options);
|
|
}
|
|
|
|
this.gravitySolver = new CentralGravitySolver(this.body, this.physicsBody, options);
|
|
this.modelOptions = options;
|
|
}
|
|
|
|
initPhysics() {
|
|
this.stabilized = false;
|
|
if (this.options.stabilization.enabled === true) {
|
|
this.stabilize();
|
|
}
|
|
else {
|
|
this.ready = true;
|
|
this.body.emitter.emit("zoomExtent", {duration:0}, true)
|
|
this.runSimulation();
|
|
}
|
|
}
|
|
|
|
stopSimulation() {
|
|
this.stabilized = true;
|
|
if (this.viewFunction !== undefined) {
|
|
this.body.emitter.off("initRedraw", this.viewFunction);
|
|
this.viewFunction = undefined;
|
|
this.body.emitter.emit("_stopRendering");
|
|
}
|
|
}
|
|
|
|
runSimulation() {
|
|
if (this.viewFunction === undefined) {
|
|
this.viewFunction = this.simulationStep.bind(this);
|
|
this.body.emitter.on("initRedraw", this.viewFunction);
|
|
this.body.emitter.emit("_startRendering");
|
|
}
|
|
}
|
|
|
|
simulationStep() {
|
|
// check if the physics have settled
|
|
var startTime = Date.now();
|
|
this.physicsTick();
|
|
var physicsTime = Date.now() - startTime;
|
|
|
|
// run double speed if it is a little graph
|
|
if ((physicsTime < 0.4 * this.simulationInterval || this.runDoubleSpeed == true) && this.stabilized === false) {
|
|
this.physicsTick();
|
|
|
|
// this makes sure there is no jitter. The decision is taken once to run it at double speed.
|
|
this.runDoubleSpeed = true;
|
|
}
|
|
|
|
if (this.stabilized === true) {
|
|
if (this.stabilizationIterations > 1) {
|
|
// trigger the "stabilized" event.
|
|
// The event is triggered on the next tick, to prevent the case that
|
|
// it is fired while initializing the Network, in which case you would not
|
|
// be able to catch it
|
|
var me = this;
|
|
var params = {
|
|
iterations: this.stabilizationIterations
|
|
};
|
|
this.stabilizationIterations = 0;
|
|
this.startedStabilization = false;
|
|
setTimeout(function () {
|
|
me.body.emitter.emit("stabilized", params);
|
|
}, 0);
|
|
}
|
|
else {
|
|
this.stabilizationIterations = 0;
|
|
}
|
|
this.stopSimulation();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* A single simulation step (or "tick") in the physics simulation
|
|
*
|
|
* @private
|
|
*/
|
|
physicsTick() {
|
|
if (this.stabilized === false) {
|
|
this.calculateForces();
|
|
this.stabilized = this.moveNodes();
|
|
|
|
// determine if the network has stabilzied
|
|
if (this.stabilized === true) {
|
|
this.revert();
|
|
}
|
|
else {
|
|
// this is here to ensure that there is no start event when the network is already stable.
|
|
if (this.startedStabilization == false) {
|
|
this.body.emitter.emit("startStabilizing");
|
|
this.startedStabilization = true;
|
|
}
|
|
}
|
|
|
|
this.stabilizationIterations++;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Smooth curves are created by adding invisible nodes in the center of the edges. These nodes are also
|
|
* handled in the calculateForces function. We then use a quadratic curve with the center node as control.
|
|
* This function joins the datanodes and invisible (called support) nodes into one object.
|
|
* We do this so we do not contaminate this.body.nodes with the support nodes.
|
|
*
|
|
* @private
|
|
*/
|
|
_updatePhysicsIndices() {
|
|
this.physicsBody.forces = {};
|
|
this.physicsBody.physicsNodeIndices = [];
|
|
this.physicsBody.physicsEdgeIndices = [];
|
|
let nodes = this.body.nodes;
|
|
let edges = this.body.edges;
|
|
|
|
// get node indices for physics
|
|
for (let nodeId in nodes) {
|
|
if (nodes.hasOwnProperty(nodeId)) {
|
|
if (nodes[nodeId].options.physics === true) {
|
|
this.physicsBody.physicsNodeIndices.push(nodeId);
|
|
}
|
|
}
|
|
}
|
|
|
|
// get edge indices for physics
|
|
for (let edgeId in edges) {
|
|
if (edges.hasOwnProperty(edgeId)) {
|
|
if (edges[edgeId].options.physics === true) {
|
|
this.physicsBody.physicsEdgeIndices.push(edgeId);
|
|
}
|
|
}
|
|
}
|
|
|
|
// get the velocity and the forces vector
|
|
for (let i = 0; i < this.physicsBody.physicsNodeIndices.length; i++) {
|
|
let nodeId = this.physicsBody.physicsNodeIndices[i];
|
|
this.physicsBody.forces[nodeId] = {x:0,y:0};
|
|
|
|
// forces can be reset because they are recalculated. Velocities have to persist.
|
|
if (this.physicsBody.velocities[nodeId] === undefined) {
|
|
this.physicsBody.velocities[nodeId] = {x:0,y:0};
|
|
}
|
|
}
|
|
|
|
// clean deleted nodes from the velocity vector
|
|
for (let nodeId in this.physicsBody.velocities) {
|
|
if (nodes[nodeId] === undefined) {
|
|
delete this.physicsBody.velocities[nodeId];
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
revert() {
|
|
var nodeIds = Object.keys(this.previousStates);
|
|
var nodes = this.body.nodes;
|
|
var velocities = this.physicsBody.velocities;
|
|
|
|
for (let i = 0; i < nodeIds.length; i++) {
|
|
let nodeId = nodeIds[i];
|
|
if (nodes[nodeId] !== undefined) {
|
|
velocities[nodeId].x = this.previousStates[nodeId].vx;
|
|
velocities[nodeId].y = this.previousStates[nodeId].vy;
|
|
nodes[nodeId].x = this.previousStates[nodeId].x;
|
|
nodes[nodeId].y = this.previousStates[nodeId].y;
|
|
}
|
|
else {
|
|
delete this.previousStates[nodeId];
|
|
}
|
|
}
|
|
}
|
|
|
|
moveNodes() {
|
|
var nodesPresent = false;
|
|
var nodeIndices = this.physicsBody.physicsNodeIndices;
|
|
var maxVelocity = this.options.maxVelocity === 0 ? 1e9 : this.options.maxVelocity;
|
|
var stabilized = true;
|
|
var vminCorrected = this.options.minVelocity / Math.max(this.body.view.scale,0.05);
|
|
|
|
for (let i = 0; i < nodeIndices.length; i++) {
|
|
let nodeId = nodeIndices[i];
|
|
let nodeVelocity = this._performStep(nodeId, maxVelocity);
|
|
// stabilized is true if stabilized is true and velocity is smaller than vmin --> all nodes must be stabilized
|
|
stabilized = nodeVelocity < vminCorrected && stabilized === true;
|
|
nodesPresent = true;
|
|
}
|
|
|
|
|
|
if (nodesPresent == true) {
|
|
if (vminCorrected > 0.5*this.options.maxVelocity) {
|
|
return false;
|
|
}
|
|
else {
|
|
return stabilized;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
_performStep(nodeId,maxVelocity) {
|
|
var node = this.body.nodes[nodeId];
|
|
var timestep = this.options.timestep;
|
|
var forces = this.physicsBody.forces;
|
|
var velocities = this.physicsBody.velocities;
|
|
|
|
// store the state so we can revert
|
|
this.previousStates[nodeId] = {x:node.x, y:node.y, vx:velocities[nodeId].x, vy:velocities[nodeId].y};
|
|
|
|
if (!node.xFixed) {
|
|
let dx = this.modelOptions.damping * velocities[nodeId].x; // damping force
|
|
let ax = (forces[nodeId].x - dx) / node.options.mass; // acceleration
|
|
velocities[nodeId].x += ax * timestep; // velocity
|
|
velocities[nodeId].x = (Math.abs(velocities[nodeId].x) > maxVelocity) ? ((velocities[nodeId].x > 0) ? maxVelocity : -maxVelocity) : velocities[nodeId].x;
|
|
node.x += velocities[nodeId].x * timestep; // position
|
|
}
|
|
else {
|
|
forces[nodeId].x = 0;
|
|
velocities[nodeId].x = 0;
|
|
}
|
|
|
|
if (!node.yFixed) {
|
|
let dy = this.modelOptions.damping * velocities[nodeId].y; // damping force
|
|
let ay = (forces[nodeId].y - dy) / node.options.mass; // acceleration
|
|
velocities[nodeId].y += ay * timestep; // velocity
|
|
velocities[nodeId].y = (Math.abs(velocities[nodeId].y) > maxVelocity) ? ((velocities[nodeId].y > 0) ? maxVelocity : -maxVelocity) : velocities[nodeId].y;
|
|
node.y += velocities[nodeId].y * timestep; // position
|
|
}
|
|
else {
|
|
forces[nodeId].y = 0;
|
|
velocities[nodeId].y = 0;
|
|
}
|
|
|
|
var totalVelocity = Math.sqrt(Math.pow(velocities[nodeId].x,2) + Math.pow(velocities[nodeId].y,2));
|
|
return totalVelocity;
|
|
}
|
|
|
|
calculateForces() {
|
|
this.gravitySolver.solve();
|
|
this.nodesSolver.solve();
|
|
this.edgesSolver.solve();
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/**
|
|
* 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
|
|
*/
|
|
_freezeNodes() {
|
|
var nodes = this.body.nodes;
|
|
for (var id in nodes) {
|
|
if (nodes.hasOwnProperty(id)) {
|
|
if (nodes[id].x != null && nodes[id].y != null) {
|
|
nodes[id].fixedData.x = nodes[id].xFixed;
|
|
nodes[id].fixedData.y = nodes[id].yFixed;
|
|
nodes[id].xFixed = true;
|
|
nodes[id].yFixed = true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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 (nodes[id].fixedData.x != null) {
|
|
nodes[id].xFixed = nodes[id].fixedData.x;
|
|
nodes[id].yFixed = nodes[id].fixedData.y;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Find a stable position for all nodes
|
|
* @private
|
|
*/
|
|
stabilize() {
|
|
if (this.options.stabilization.onlyDynamicEdges == true) {
|
|
this._freezeNodes();
|
|
}
|
|
this.stabilizationSteps = 0;
|
|
|
|
setTimeout(this._stabilizationBatch.bind(this),0);
|
|
}
|
|
|
|
_stabilizationBatch() {
|
|
var count = 0;
|
|
while (this.stabilized == false && count < this.options.stabilization.updateInterval && this.stabilizationSteps < this.options.stabilization.iterations) {
|
|
this.physicsTick();
|
|
this.stabilizationSteps++;
|
|
count++;
|
|
}
|
|
|
|
if (this.stabilized == false && this.stabilizationSteps < this.options.stabilization.iterations) {
|
|
this.body.emitter.emit("stabilizationProgress", {steps: this.stabilizationSteps, total: this.options.stabilization.iterations});
|
|
setTimeout(this._stabilizationBatch.bind(this),0);
|
|
}
|
|
else {
|
|
this._finalizeStabilization();
|
|
}
|
|
}
|
|
|
|
_finalizeStabilization() {
|
|
if (this.options.stabilization.zoomExtent == true) {
|
|
this.body.emitter.emit("zoomExtent", {duration:0});
|
|
}
|
|
|
|
if (this.options.stabilization.onlyDynamicEdges == true) {
|
|
this._restoreFrozenNodes();
|
|
}
|
|
|
|
this.body.emitter.emit("stabilizationIterationsDone");
|
|
this.body.emitter.emit("_requestRedraw");
|
|
this.ready = true;
|
|
}
|
|
|
|
}
|
|
|
|
export default PhysicsEngine;
|