jrtechs
/
jrtechs-vis
mirror of https://github.com/jrtechs/vis.git
1
0
Fork 0
Code Issues 0 Releases 82 Wiki Activity
Browse Source

first step to modularize the physics engine

flowchartTest
Alex de Mulder 10 years ago
parent
093cb73de5
commit
b91757fabf
10 changed files with 603 additions and 569 deletions
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. +1
    -2
      dist/vis.js
  2. +1
    -1
      lib/network/Network.js
  3. +1
    -1
      lib/network/modules/Clustering.js
  4. +25
    -23
      lib/network/modules/PhysicsEngine.js
  5. +0
    -409
      lib/network/modules/components/BarnesHutSolver.js
  6. +0
    -32
      lib/network/modules/components/CentralGravitySolver.js
  7. +0
    -101
      lib/network/modules/components/SpringSolver.js
  8. +434
    -0
      lib/network/modules/components/physics/BarnesHutSolver.js
  9. +32
    -0
      lib/network/modules/components/physics/CentralGravitySolver.js
  10. +109
    -0
      lib/network/modules/components/physics/SpringSolver.js

+ 1
- 2
dist/vis.js View File

@ -23120,8 +23120,8 @@ return /******/ (function(modules) { // webpackBootstrap
}
var me = this;
// this event will trigger a rebuilding of the cache of colors, nodes etc.
this.on("_dataChanged", function () {
console.log("here");
me._updateNodeIndexList();
me._updateCalculationNodes();
me._markAllEdgesAsDirty();
@ -34441,7 +34441,6 @@ return /******/ (function(modules) { // webpackBootstrap
var ClusterEngine = (function () {
function ClusterEngine(body) {
var options = arguments[1] === undefined ? {} : arguments[1];
_classCallCheck(this, ClusterEngine);
this.body = body;

+ 1
- 1
lib/network/Network.js View File

@ -374,8 +374,8 @@ function Network (container, data, options) {
}
var me = this;
// this event will trigger a rebuilding of the cache of colors, nodes etc.
this.on("_dataChanged", function () {
console.log("here")
me._updateNodeIndexList();
me._updateCalculationNodes();
me._markAllEdgesAsDirty();

+ 1
- 1
lib/network/modules/Clustering.js View File

@ -5,7 +5,7 @@
var util = require("../../util");
class ClusterEngine {
constructor(body, options={}) {
constructor(body) {
this.body = body;
this.clusteredNodes = {};
}

+ 25
- 23
lib/network/modules/PhysicsEngine.js View File

@ -2,32 +2,34 @@
* Created by Alex on 2/23/2015.
*/
var BarnesHut = require("./compontents/BarnesHutSolver")
var SpringSolver = require("./compontents/SpringSolver")
var CentralGravitySolver = require("./compontents/CentralGravitySolver")
import {BarnesHut} from "./components/physics/BarnesHutSolver";
import {SpringSolver} from "./components/physics/SpringSolver";
import {CentralGravitySolver} from "./components/physics/CentralGravitySolver";
function PhysicsEngine(body, options) {
this.body = body;
class PhysicsEngine {
constructor(body, options) {
this.body = body;
this.nodesSolver = new BarnesHut(body, options);
this.edgesSolver = new SpringSolver(body, options);
this.gravitySolver = new CentralGravitySolver(body, options);
}
this.nodesSolver = new BarnesHut(body, options);
this.edgesSolver = new SpringSolver(body, options);
this.gravitySolver = new CentralGravitySolver(body, options);
}
PhysicsEngine.prototype.calculateField = function () {
this.nodesSolver.solve();
};
calculateField() {
this.nodesSolver.solve();
};
PhysicsEngine.prototype.calculateSprings = function () {
this.edgesSolver.solve();
};
calculateSprings() {
this.edgesSolver.solve();
};
PhysicsEngine.prototype.calculateCentralGravity = function () {
this.gravitySolver.solve();
};
calculateCentralGravity() {
this.gravitySolver.solve();
};
PhysicsEngine.prototype.calculate = function () {
this.calculateCentralGravity();
this.calculateField();
this.calculateSprings();
};
calculate() {
this.calculateCentralGravity();
this.calculateField();
this.calculateSprings();
};
}

+ 0
- 409
lib/network/modules/components/BarnesHutSolver.js View File

@ -1,409 +0,0 @@
/**
* Created by Alex on 2/23/2015.
*/
function BarnesHutSolver(body, options) {
this.body = body;
this.options = options;
}
/**
* This function calculates the forces the nodes apply on eachother based on a gravitational model.
* The Barnes Hut method is used to speed up this N-body simulation.
*
* @private
*/
BarnesHutSolver.prototype.solve = function() {
if (this.options.gravitationalConstant != 0) {
var node;
var nodes = this.body.calculationNodes;
var nodeIndices = this.body.calculationNodeIndices;
var nodeCount = nodeIndices.length;
var barnesHutTree = this._formBarnesHutTree(nodes,nodeIndices);
// place the nodes one by one recursively
for (var i = 0; i < nodeCount; i++) {
node = nodes[nodeIndices[i]];
if (node.options.mass > 0) {
// starting with root is irrelevant, it never passes the BarnesHutSolver condition
this._getForceContribution(barnesHutTree.root.children.NW,node);
this._getForceContribution(barnesHutTree.root.children.NE,node);
this._getForceContribution(barnesHutTree.root.children.SW,node);
this._getForceContribution(barnesHutTree.root.children.SE,node);
}
}
}
};
/**
* This function traverses the barnesHutTree. It checks when it can approximate distant nodes with their center of mass.
* If a region contains a single node, we check if it is not itself, then we apply the force.
*
* @param parentBranch
* @param node
* @private
*/
BarnesHutSolver.prototype._getForceContribution = function(parentBranch,node) {
// we get no force contribution from an empty region
if (parentBranch.childrenCount > 0) {
var dx,dy,distance;
// get the distance from the center of mass to the node.
dx = parentBranch.centerOfMass.x - node.x;
dy = parentBranch.centerOfMass.y - node.y;
distance = Math.sqrt(dx * dx + dy * dy);
// BarnesHutSolver condition
// original condition : s/d < thetaInverted = passed === d/s > 1/theta = passed
// calcSize = 1/s --> d * 1/s > 1/theta = passed
if (distance * parentBranch.calcSize > this.options.thetaInverted) {
// duplicate code to reduce function calls to speed up program
if (distance == 0) {
distance = 0.1*Math.random();
dx = distance;
}
var gravityForce = this.options.gravitationalConstant * parentBranch.mass * node.options.mass / (distance * distance * distance);
var fx = dx * gravityForce;
var fy = dy * gravityForce;
node.fx += fx;
node.fy += fy;
}
else {
// Did not pass the condition, go into children if available
if (parentBranch.childrenCount == 4) {
this._getForceContribution(parentBranch.children.NW,node);
this._getForceContribution(parentBranch.children.NE,node);
this._getForceContribution(parentBranch.children.SW,node);
this._getForceContribution(parentBranch.children.SE,node);
}
else { // parentBranch must have only one node, if it was empty we wouldnt be here
if (parentBranch.children.data.id != node.id) { // if it is not self
// duplicate code to reduce function calls to speed up program
if (distance == 0) {
distance = 0.5*Math.random();
dx = distance;
}
var gravityForce = this.options.gravitationalConstant * parentBranch.mass * node.options.mass / (distance * distance * distance);
var fx = dx * gravityForce;
var fy = dy * gravityForce;
node.fx += fx;
node.fy += fy;
}
}
}
}
};
/**
* This function constructs the barnesHut tree recursively. It creates the root, splits it and starts placing the nodes.
*
* @param nodes
* @param nodeIndices
* @private
*/
BarnesHutSolver.prototype._formBarnesHutTree = function(nodes,nodeIndices) {
var node;
var nodeCount = nodeIndices.length;
var minX = Number.MAX_VALUE,
minY = Number.MAX_VALUE,
maxX =-Number.MAX_VALUE,
maxY =-Number.MAX_VALUE;
// get the range of the nodes
for (var i = 0; i < nodeCount; i++) {
var x = nodes[nodeIndices[i]].x;
var y = nodes[nodeIndices[i]].y;
if (nodes[nodeIndices[i]].options.mass > 0) {
if (x < minX) { minX = x; }
if (x > maxX) { maxX = x; }
if (y < minY) { minY = y; }
if (y > maxY) { maxY = y; }
}
}
// make the range a square
var sizeDiff = Math.abs(maxX - minX) - Math.abs(maxY - minY); // difference between X and Y
if (sizeDiff > 0) {minY -= 0.5 * sizeDiff; maxY += 0.5 * sizeDiff;} // xSize > ySize
else {minX += 0.5 * sizeDiff; maxX -= 0.5 * sizeDiff;} // xSize < ySize
var minimumTreeSize = 1e-5;
var rootSize = Math.max(minimumTreeSize,Math.abs(maxX - minX));
var halfRootSize = 0.5 * rootSize;
var centerX = 0.5 * (minX + maxX), centerY = 0.5 * (minY + maxY);
// construct the barnesHutTree
var barnesHutTree = {
root:{
centerOfMass: {x:0, y:0},
mass:0,
range: {
minX: centerX-halfRootSize,maxX:centerX+halfRootSize,
minY: centerY-halfRootSize,maxY:centerY+halfRootSize
},
size: rootSize,
calcSize: 1 / rootSize,
children: { data:null},
maxWidth: 0,
level: 0,
childrenCount: 4
}
};
this._splitBranch(barnesHutTree.root);
// place the nodes one by one recursively
for (i = 0; i < nodeCount; i++) {
node = nodes[nodeIndices[i]];
if (node.options.mass > 0) {
this._placeInTree(barnesHutTree.root,node);
}
}
// make global
return barnesHutTree
};
/**
* this updates the mass of a branch. this is increased by adding a node.
*
* @param parentBranch
* @param node
* @private
*/
BarnesHutSolver.prototype._updateBranchMass = function(parentBranch, node) {
var totalMass = parentBranch.mass + node.options.mass;
var totalMassInv = 1/totalMass;
parentBranch.centerOfMass.x = parentBranch.centerOfMass.x * parentBranch.mass + node.x * node.options.mass;
parentBranch.centerOfMass.x *= totalMassInv;
parentBranch.centerOfMass.y = parentBranch.centerOfMass.y * parentBranch.mass + node.y * node.options.mass;
parentBranch.centerOfMass.y *= totalMassInv;
parentBranch.mass = totalMass;
var biggestSize = Math.max(Math.max(node.height,node.radius),node.width);
parentBranch.maxWidth = (parentBranch.maxWidth < biggestSize) ? biggestSize : parentBranch.maxWidth;
};
/**
* determine in which branch the node will be placed.
*
* @param parentBranch
* @param node
* @param skipMassUpdate
* @private
*/
BarnesHutSolver.prototype._placeInTree = function(parentBranch,node,skipMassUpdate) {
if (skipMassUpdate != true || skipMassUpdate === undefined) {
// update the mass of the branch.
this._updateBranchMass(parentBranch,node);
}
if (parentBranch.children.NW.range.maxX > node.x) { // in NW or SW
if (parentBranch.children.NW.range.maxY > node.y) { // in NW
this._placeInRegion(parentBranch,node,"NW");
}
else { // in SW
this._placeInRegion(parentBranch,node,"SW");
}
}
else { // in NE or SE
if (parentBranch.children.NW.range.maxY > node.y) { // in NE
this._placeInRegion(parentBranch,node,"NE");
}
else { // in SE
this._placeInRegion(parentBranch,node,"SE");
}
}
};
/**
* actually place the node in a region (or branch)
*
* @param parentBranch
* @param node
* @param region
* @private
*/
BarnesHutSolver.prototype._placeInRegion = function(parentBranch,node,region) {
switch (parentBranch.children[region].childrenCount) {
case 0: // place node here
parentBranch.children[region].children.data = node;
parentBranch.children[region].childrenCount = 1;
this._updateBranchMass(parentBranch.children[region],node);
break;
case 1: // convert into children
// if there are two nodes exactly overlapping (on init, on opening of cluster etc.)
// we move one node a pixel and we do not put it in the tree.
if (parentBranch.children[region].children.data.x == node.x &&
parentBranch.children[region].children.data.y == node.y) {
node.x += Math.random();
node.y += Math.random();
}
else {
this._splitBranch(parentBranch.children[region]);
this._placeInTree(parentBranch.children[region],node);
}
break;
case 4: // place in branch
this._placeInTree(parentBranch.children[region],node);
break;
}
};
/**
* this function splits a branch into 4 sub branches. If the branch contained a node, we place it in the subbranch
* after the split is complete.
*
* @param parentBranch
* @private
*/
BarnesHutSolver.prototype._splitBranch = function(parentBranch) {
// if the branch is shaded with a node, replace the node in the new subset.
var containedNode = null;
if (parentBranch.childrenCount == 1) {
containedNode = parentBranch.children.data;
parentBranch.mass = 0; parentBranch.centerOfMass.x = 0; parentBranch.centerOfMass.y = 0;
}
parentBranch.childrenCount = 4;
parentBranch.children.data = null;
this._insertRegion(parentBranch,"NW");
this._insertRegion(parentBranch,"NE");
this._insertRegion(parentBranch,"SW");
this._insertRegion(parentBranch,"SE");
if (containedNode != null) {
this._placeInTree(parentBranch,containedNode);
}
};
/**
* This function subdivides the region into four new segments.
* Specifically, this inserts a single new segment.
* It fills the children section of the parentBranch
*
* @param parentBranch
* @param region
* @param parentRange
* @private
*/
BarnesHutSolver.prototype._insertRegion = function(parentBranch, region) {
var minX,maxX,minY,maxY;
var childSize = 0.5 * parentBranch.size;
switch (region) {
case "NW":
minX = parentBranch.range.minX;
maxX = parentBranch.range.minX + childSize;
minY = parentBranch.range.minY;
maxY = parentBranch.range.minY + childSize;
break;
case "NE":
minX = parentBranch.range.minX + childSize;
maxX = parentBranch.range.maxX;
minY = parentBranch.range.minY;
maxY = parentBranch.range.minY + childSize;
break;
case "SW":
minX = parentBranch.range.minX;
maxX = parentBranch.range.minX + childSize;
minY = parentBranch.range.minY + childSize;
maxY = parentBranch.range.maxY;
break;
case "SE":
minX = parentBranch.range.minX + childSize;
maxX = parentBranch.range.maxX;
minY = parentBranch.range.minY + childSize;
maxY = parentBranch.range.maxY;
break;
}
parentBranch.children[region] = {
centerOfMass:{x:0,y:0},
mass:0,
range:{minX:minX,maxX:maxX,minY:minY,maxY:maxY},
size: 0.5 * parentBranch.size,
calcSize: 2 * parentBranch.calcSize,
children: {data:null},
maxWidth: 0,
level: parentBranch.level+1,
childrenCount: 0
};
};
/**
* This function is for debugging purposed, it draws the tree.
*
* @param ctx
* @param color
* @private
*/
BarnesHutSolver.prototype._drawTree = function(ctx,color) {
if (this.barnesHutTree !== undefined) {
ctx.lineWidth = 1;
this._drawBranch(this.barnesHutTree.root,ctx,color);
}
};
/**
* This function is for debugging purposes. It draws the branches recursively.
*
* @param branch
* @param ctx
* @param color
* @private
*/
BarnesHutSolver.prototype._drawBranch = function(branch,ctx,color) {
if (color === undefined) {
color = "#FF0000";
}
if (branch.childrenCount == 4) {
this._drawBranch(branch.children.NW,ctx);
this._drawBranch(branch.children.NE,ctx);
this._drawBranch(branch.children.SE,ctx);
this._drawBranch(branch.children.SW,ctx);
}
ctx.strokeStyle = color;
ctx.beginPath();
ctx.moveTo(branch.range.minX,branch.range.minY);
ctx.lineTo(branch.range.maxX,branch.range.minY);
ctx.stroke();
ctx.beginPath();
ctx.moveTo(branch.range.maxX,branch.range.minY);
ctx.lineTo(branch.range.maxX,branch.range.maxY);
ctx.stroke();
ctx.beginPath();
ctx.moveTo(branch.range.maxX,branch.range.maxY);
ctx.lineTo(branch.range.minX,branch.range.maxY);
ctx.stroke();
ctx.beginPath();
ctx.moveTo(branch.range.minX,branch.range.maxY);
ctx.lineTo(branch.range.minX,branch.range.minY);
ctx.stroke();
/*
if (branch.mass > 0) {
ctx.circle(branch.centerOfMass.x, branch.centerOfMass.y, 3*branch.mass);
ctx.stroke();
}
*/
};
module.exports = BarnesHutSolver;

+ 0
- 32
lib/network/modules/components/CentralGravitySolver.js View File

@ -1,32 +0,0 @@
/**
* Created by Alex on 2/23/2015.
*/
function CentralGravitySolver(body, options) {
this.body = body;
this.options = options;
}
CentralGravitySolver.prototype.solve = function () {
var dx, dy, distance, node, i;
var nodes = this.body.calculationNodes;
var gravity = this.options.centralGravity;
var gravityForce = 0;
for (i = 0; i < this.body.calculationNodeIndices.length; i++) {
node = nodes[this.body.calculationNodeIndices[i]];
node.damping = this.options.damping; // possibly add function to alter damping properties of clusters.
dx = -node.x;
dy = -node.y;
distance = Math.sqrt(dx * dx + dy * dy);
gravityForce = (distance == 0) ? 0 : (gravity / distance);
node.fx = dx * gravityForce;
node.fy = dy * gravityForce;
}
};
module.exports = CentralGravitySolver;

+ 0
- 101
lib/network/modules/components/SpringSolver.js View File

@ -1,101 +0,0 @@
/**
* Created by Alex on 2/23/2015.
*/
function SpringSolver(body, options) {
this.body = body;
this.options = options;
}
/**
* this function calculates the effects of the springs in the case of unsmooth curves.
*
* @private
*/
SpringSolver.prototype._calculateSpringForces = function () {
var edgeLength, edge, edgeId;
var edges = this.edges;
// forces caused by the edges, modelled as springs
for (edgeId in edges) {
if (edges.hasOwnProperty(edgeId)) {
edge = edges[edgeId];
if (edge.connected === true) {
// only calculate forces if nodes are in the same sector
if (this.nodes.hasOwnProperty(edge.toId) && this.nodes.hasOwnProperty(edge.fromId)) {
edgeLength = edge.physics.springLength;
this._calculateSpringForce(edge.from, edge.to, edgeLength);
}
}
}
}
};
/**
* This function calculates the springforces on the nodes, accounting for the support nodes.
*
* @private
*/
SpringSolver.prototype._calculateSpringForcesWithSupport = function () {
var edgeLength, edge, edgeId;
var edges = this.edges;
// forces caused by the edges, modelled as springs
for (edgeId in edges) {
if (edges.hasOwnProperty(edgeId)) {
edge = edges[edgeId];
if (edge.connected === true) {
// only calculate forces if nodes are in the same sector
if (this.nodes.hasOwnProperty(edge.toId) && this.nodes.hasOwnProperty(edge.fromId)) {
if (edge.via != null) {
var node1 = edge.to;
var node2 = edge.via;
var node3 = edge.from;
edgeLength = edge.physics.springLength;
this._calculateSpringForce(node1, node2, 0.5 * edgeLength);
this._calculateSpringForce(node2, node3, 0.5 * edgeLength);
}
}
}
}
}
};
/**
* This is the code actually performing the calculation for the function above. It is split out to avoid repetition.
*
* @param node1
* @param node2
* @param edgeLength
* @private
*/
SpringSolver.prototype._calculateSpringForce = function (node1, node2, edgeLength) {
var dx, dy, fx, fy, springForce, distance;
dx = (node1.x - node2.x);
dy = (node1.y - node2.y);
distance = Math.sqrt(dx * dx + dy * dy);
distance = distance == 0 ? 0.01 : distance;
// the 1/distance is so the fx and fy can be calculated without sine or cosine.
springForce = this.options.springConstant * (edgeLength - distance) / distance;
fx = dx * springForce;
fy = dy * springForce;
node1.fx += fx;
node1.fy += fy;
node2.fx -= fx;
node2.fy -= fy;
};
module.exports = SpringSolver;

+ 434
- 0
lib/network/modules/components/physics/BarnesHutSolver.js View File

@ -0,0 +1,434 @@
/**
* Created by Alex on 2/23/2015.
*/
class BarnesHutSolver {
constructor(body, options) {
this.body = body;
this.options = options;
}
/**
* This function calculates the forces the nodes apply on eachother based on a gravitational model.
* The Barnes Hut method is used to speed up this N-body simulation.
*
* @private
*/
solve() {
if (this.options.gravitationalConstant != 0) {
var node;
var nodes = this.body.calculationNodes;
var nodeIndices = this.body.calculationNodeIndices;
var nodeCount = nodeIndices.length;
var barnesHutTree = this._formBarnesHutTree(nodes, nodeIndices);
// place the nodes one by one recursively
for (var i = 0; i < nodeCount; i++) {
node = nodes[nodeIndices[i]];
if (node.options.mass > 0) {
// starting with root is irrelevant, it never passes the BarnesHutSolver condition
this._getForceContribution(barnesHutTree.root.children.NW, node);
this._getForceContribution(barnesHutTree.root.children.NE, node);
this._getForceContribution(barnesHutTree.root.children.SW, node);
this._getForceContribution(barnesHutTree.root.children.SE, node);
}
}
}
}
/**
* This function traverses the barnesHutTree. It checks when it can approximate distant nodes with their center of mass.
* If a region contains a single node, we check if it is not itself, then we apply the force.
*
* @param parentBranch
* @param node
* @private
*/
_getForceContribution(parentBranch, node) {
// we get no force contribution from an empty region
if (parentBranch.childrenCount > 0) {
var dx, dy, distance;
// get the distance from the center of mass to the node.
dx = parentBranch.centerOfMass.x - node.x;
dy = parentBranch.centerOfMass.y - node.y;
distance = Math.sqrt(dx * dx + dy * dy);
// BarnesHutSolver condition
// original condition : s/d < thetaInverted = passed === d/s > 1/theta = passed
// calcSize = 1/s --> d * 1/s > 1/theta = passed
if (distance * parentBranch.calcSize > this.options.thetaInverted) {
// duplicate code to reduce function calls to speed up program
if (distance == 0) {
distance = 0.1 * Math.random();
dx = distance;
}
var gravityForce = this.options.gravitationalConstant * parentBranch.mass * node.options.mass / (distance * distance * distance);
var fx = dx * gravityForce;
var fy = dy * gravityForce;
node.fx += fx;
node.fy += fy;
}
else {
// Did not pass the condition, go into children if available
if (parentBranch.childrenCount == 4) {
this._getForceContribution(parentBranch.children.NW, node);
this._getForceContribution(parentBranch.children.NE, node);
this._getForceContribution(parentBranch.children.SW, node);
this._getForceContribution(parentBranch.children.SE, node);
}
else { // parentBranch must have only one node, if it was empty we wouldnt be here
if (parentBranch.children.data.id != node.id) { // if it is not self
// duplicate code to reduce function calls to speed up program
if (distance == 0) {
distance = 0.5 * Math.random();
dx = distance;
}
var gravityForce = this.options.gravitationalConstant * parentBranch.mass * node.options.mass / (distance * distance * distance);
var fx = dx * gravityForce;
var fy = dy * gravityForce;
node.fx += fx;
node.fy += fy;
}
}
}
}
}
/**
* This function constructs the barnesHut tree recursively. It creates the root, splits it and starts placing the nodes.
*
* @param nodes
* @param nodeIndices
* @private
*/
_formBarnesHutTree(nodes, nodeIndices) {
var node;
var nodeCount = nodeIndices.length;
var minX = Number.MAX_VALUE,
minY = Number.MAX_VALUE,
maxX = -Number.MAX_VALUE,
maxY = -Number.MAX_VALUE;
// get the range of the nodes
for (var i = 0; i < nodeCount; i++) {
var x = nodes[nodeIndices[i]].x;
var y = nodes[nodeIndices[i]].y;
if (nodes[nodeIndices[i]].options.mass > 0) {
if (x < minX) {
minX = x;
}
if (x > maxX) {
maxX = x;
}
if (y < minY) {
minY = y;
}
if (y > maxY) {
maxY = y;
}
}
}
// make the range a square
var sizeDiff = Math.abs(maxX - minX) - Math.abs(maxY - minY); // difference between X and Y
if (sizeDiff > 0) {
minY -= 0.5 * sizeDiff;
maxY += 0.5 * sizeDiff;
} // xSize > ySize
else {
minX += 0.5 * sizeDiff;
maxX -= 0.5 * sizeDiff;
} // xSize < ySize
var minimumTreeSize = 1e-5;
var rootSize = Math.max(minimumTreeSize, Math.abs(maxX - minX));
var halfRootSize = 0.5 * rootSize;
var centerX = 0.5 * (minX + maxX), centerY = 0.5 * (minY + maxY);
// construct the barnesHutTree
var barnesHutTree = {
root: {
centerOfMass: {x: 0, y: 0},
mass: 0,
range: {
minX: centerX - halfRootSize, maxX: centerX + halfRootSize,
minY: centerY - halfRootSize, maxY: centerY + halfRootSize
},
size: rootSize,
calcSize: 1 / rootSize,
children: {data: null},
maxWidth: 0,
level: 0,
childrenCount: 4
}
};
this._splitBranch(barnesHutTree.root);
// place the nodes one by one recursively
for (i = 0; i < nodeCount; i++) {
node = nodes[nodeIndices[i]];
if (node.options.mass > 0) {
this._placeInTree(barnesHutTree.root, node);
}
}
// make global
return barnesHutTree
}
/**
* this updates the mass of a branch. this is increased by adding a node.
*
* @param parentBranch
* @param node
* @private
*/
_updateBranchMass(parentBranch, node) {
var totalMass = parentBranch.mass + node.options.mass;
var totalMassInv = 1 / totalMass;
parentBranch.centerOfMass.x = parentBranch.centerOfMass.x * parentBranch.mass + node.x * node.options.mass;
parentBranch.centerOfMass.x *= totalMassInv;
parentBranch.centerOfMass.y = parentBranch.centerOfMass.y * parentBranch.mass + node.y * node.options.mass;
parentBranch.centerOfMass.y *= totalMassInv;
parentBranch.mass = totalMass;
var biggestSize = Math.max(Math.max(node.height, node.radius), node.width);
parentBranch.maxWidth = (parentBranch.maxWidth < biggestSize) ? biggestSize : parentBranch.maxWidth;
}
/**
* determine in which branch the node will be placed.
*
* @param parentBranch
* @param node
* @param skipMassUpdate
* @private
*/
_placeInTree(parentBranch, node, skipMassUpdate) {
if (skipMassUpdate != true || skipMassUpdate === undefined) {
// update the mass of the branch.
this._updateBranchMass(parentBranch, node);
}
if (parentBranch.children.NW.range.maxX > node.x) { // in NW or SW
if (parentBranch.children.NW.range.maxY > node.y) { // in NW
this._placeInRegion(parentBranch, node, "NW");
}
else { // in SW
this._placeInRegion(parentBranch, node, "SW");
}
}
else { // in NE or SE
if (parentBranch.children.NW.range.maxY > node.y) { // in NE
this._placeInRegion(parentBranch, node, "NE");
}
else { // in SE
this._placeInRegion(parentBranch, node, "SE");
}
}
}
/**
* actually place the node in a region (or branch)
*
* @param parentBranch
* @param node
* @param region
* @private
*/
_placeInRegion(parentBranch, node, region) {
switch (parentBranch.children[region].childrenCount) {
case 0: // place node here
parentBranch.children[region].children.data = node;
parentBranch.children[region].childrenCount = 1;
this._updateBranchMass(parentBranch.children[region], node);
break;
case 1: // convert into children
// if there are two nodes exactly overlapping (on init, on opening of cluster etc.)
// we move one node a pixel and we do not put it in the tree.
if (parentBranch.children[region].children.data.x == node.x &&
parentBranch.children[region].children.data.y == node.y) {
node.x += Math.random();
node.y += Math.random();
}
else {
this._splitBranch(parentBranch.children[region]);
this._placeInTree(parentBranch.children[region], node);
}
break;
case 4: // place in branch
this._placeInTree(parentBranch.children[region], node);
break;
}
}
/**
* this function splits a branch into 4 sub branches. If the branch contained a node, we place it in the subbranch
* after the split is complete.
*
* @param parentBranch
* @private
*/
_splitBranch(parentBranch) {
// if the branch is shaded with a node, replace the node in the new subset.
var containedNode = null;
if (parentBranch.childrenCount == 1) {
containedNode = parentBranch.children.data;
parentBranch.mass = 0;
parentBranch.centerOfMass.x = 0;
parentBranch.centerOfMass.y = 0;
}
parentBranch.childrenCount = 4;
parentBranch.children.data = null;
this._insertRegion(parentBranch, "NW");
this._insertRegion(parentBranch, "NE");
this._insertRegion(parentBranch, "SW");
this._insertRegion(parentBranch, "SE");
if (containedNode != null) {
this._placeInTree(parentBranch, containedNode);
}
}
/**
* This function subdivides the region into four new segments.
* Specifically, this inserts a single new segment.
* It fills the children section of the parentBranch
*
* @param parentBranch
* @param region
* @param parentRange
* @private
*/
_insertRegion(parentBranch, region) {
var minX, maxX, minY, maxY;
var childSize = 0.5 * parentBranch.size;
switch (region) {
case "NW":
minX = parentBranch.range.minX;
maxX = parentBranch.range.minX + childSize;
minY = parentBranch.range.minY;
maxY = parentBranch.range.minY + childSize;
break;
case "NE":
minX = parentBranch.range.minX + childSize;
maxX = parentBranch.range.maxX;
minY = parentBranch.range.minY;
maxY = parentBranch.range.minY + childSize;
break;
case "SW":
minX = parentBranch.range.minX;
maxX = parentBranch.range.minX + childSize;
minY = parentBranch.range.minY + childSize;
maxY = parentBranch.range.maxY;
break;
case "SE":
minX = parentBranch.range.minX + childSize;
maxX = parentBranch.range.maxX;
minY = parentBranch.range.minY + childSize;
maxY = parentBranch.range.maxY;
break;
}
parentBranch.children[region] = {
centerOfMass: {x: 0, y: 0},
mass: 0,
range: {minX: minX, maxX: maxX, minY: minY, maxY: maxY},
size: 0.5 * parentBranch.size,
calcSize: 2 * parentBranch.calcSize,
children: {data: null},
maxWidth: 0,
level: parentBranch.level + 1,
childrenCount: 0
};
}
//--------------------------- DEBUGGING BELOW ---------------------------//
/**
* This function is for debugging purposed, it draws the tree.
*
* @param ctx
* @param color
* @private
*/
_drawTree(ctx, color) {
if (this.barnesHutTree !== undefined) {
ctx.lineWidth = 1;
this._drawBranch(this.barnesHutTree.root, ctx, color);
}
}
/**
* This function is for debugging purposes. It draws the branches recursively.
*
* @param branch
* @param ctx
* @param color
* @private
*/
_drawBranch(branch, ctx, color) {
if (color === undefined) {
color = "#FF0000";
}
if (branch.childrenCount == 4) {
this._drawBranch(branch.children.NW, ctx);
this._drawBranch(branch.children.NE, ctx);
this._drawBranch(branch.children.SE, ctx);
this._drawBranch(branch.children.SW, ctx);
}
ctx.strokeStyle = color;
ctx.beginPath();
ctx.moveTo(branch.range.minX, branch.range.minY);
ctx.lineTo(branch.range.maxX, branch.range.minY);
ctx.stroke();
ctx.beginPath();
ctx.moveTo(branch.range.maxX, branch.range.minY);
ctx.lineTo(branch.range.maxX, branch.range.maxY);
ctx.stroke();
ctx.beginPath();
ctx.moveTo(branch.range.maxX, branch.range.maxY);
ctx.lineTo(branch.range.minX, branch.range.maxY);
ctx.stroke();
ctx.beginPath();
ctx.moveTo(branch.range.minX, branch.range.maxY);
ctx.lineTo(branch.range.minX, branch.range.minY);
ctx.stroke();
/*
if (branch.mass > 0) {
ctx.circle(branch.centerOfMass.x, branch.centerOfMass.y, 3*branch.mass);
ctx.stroke();
}
*/
}
}
export {BarnesHutSolver};

+ 32
- 0
lib/network/modules/components/physics/CentralGravitySolver.js View File

@ -0,0 +1,32 @@
/**
* Created by Alex on 2/23/2015.
*/
class CentralGravitySolver {
constructor(body, options) {
this.body = body;
this.options = options;
}
solve() {
var dx, dy, distance, node, i;
var nodes = this.body.calculationNodes;
var gravity = this.options.centralGravity;
var gravityForce = 0;
var calculationNodeIndices = this.body.calculationNodeIndices;
for (i = 0; i < calculationNodeIndices.length; i++) {
node = nodes[calculationNodeIndices[i]];
dx = -node.x;
dy = -node.y;
distance = Math.sqrt(dx * dx + dy * dy);
gravityForce = (distance == 0) ? 0 : (gravity / distance);
node.fx = dx * gravityForce;
node.fy = dy * gravityForce;
}
}
}
export {CentralGravitySolver};

+ 109
- 0
lib/network/modules/components/physics/SpringSolver.js View File

@ -0,0 +1,109 @@
/**
* Created by Alex on 2/23/2015.
*/
class SpringSolver {
constructor(body, options) {
this.body = body;
this.options = options;
}
solve() {
if (this.options.smoothCurves.enabled == true && this.options.smoothCurves.dynamic == true) {
this._calculateSpringForcesWithSupport();
}
else {
this._calculateSpringForces();
}
}
/**
* this function calculates the effects of the springs in the case of unsmooth curves.
*
* @private
*/
_calculateSpringForces() {
var edgeLength, edge, edgeId;
var edges = this.edges;
// forces caused by the edges, modelled as springs
for (edgeId in edges) {
if (edges.hasOwnProperty(edgeId)) {
edge = edges[edgeId];
if (edge.connected === true) {
// only calculate forces if nodes are in the same sector
if (this.nodes.hasOwnProperty(edge.toId) && this.nodes.hasOwnProperty(edge.fromId)) {
edgeLength = edge.physics.springLength;
this._calculateSpringForce(edge.from, edge.to, edgeLength);
}
}
}
}
}
/**
* This function calculates the springforces on the nodes, accounting for the support nodes.
*
* @private
*/
_calculateSpringForcesWithSupport() {
var edgeLength, edge, edgeId;
var edges = this.edges;
// forces caused by the edges, modelled as springs
for (edgeId in edges) {
if (edges.hasOwnProperty(edgeId)) {
edge = edges[edgeId];
if (edge.connected === true) {
// only calculate forces if nodes are in the same sector
if (this.nodes.hasOwnProperty(edge.toId) && this.nodes.hasOwnProperty(edge.fromId)) {
if (edge.via != null) {
var node1 = edge.to;
var node2 = edge.via;
var node3 = edge.from;
edgeLength = edge.physics.springLength;
this._calculateSpringForce(node1, node2, 0.5 * edgeLength);
this._calculateSpringForce(node2, node3, 0.5 * edgeLength);
}
}
}
}
}
}
/**
* This is the code actually performing the calculation for the function above. It is split out to avoid repetition.
*
* @param node1
* @param node2
* @param edgeLength
* @private
*/
_calculateSpringForce(node1, node2, edgeLength) {
var dx, dy, fx, fy, springForce, distance;
dx = (node1.x - node2.x);
dy = (node1.y - node2.y);
distance = Math.sqrt(dx * dx + dy * dy);
distance = distance == 0 ? 0.01 : distance;
// the 1/distance is so the fx and fy can be calculated without sine or cosine.
springForce = this.options.springConstant * (edgeLength - distance) / distance;
fx = dx * springForce;
fy = dy * springForce;
node1.fx += fx;
node1.fy += fy;
node2.fx -= fx;
node2.fy -= fy;
}
}
export {SpringSolver};

Write Preview
Loading…
Cancel
Save