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IndexProgramming Questions & HelpPrograms › Lee Byron's library Modification
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Lee Byron's library Modification (Read 1402 times)
Lee Byron's library Modification
May 31st, 2010, 4:56am

I am very new to Processing (and Scripting / Java in general)...

Currently, I am trying to modify the Lee Byron's Mesh to make the points move. I managed to make them move, but now I would like to make the points that are closer to each other faster.

I also tried to add new points (saw the code in discourse) but it did not work)

I could use PVector to find distances between points and than have them move faster over time but I am not sure how to go about it. (its the last part in this code) . sorry if it looks messy- my code is divided into tabs and im not sure (yet) how to display this in discourse forums..

Here is the code:

(divided in 3 tabs):

import megamu.mesh.*;

void setup() {                  
 // initialize points and calculate diagrams

void draw() {

void keyPressed() {
 // reset points and mesh when spacebar is pressed
 if(key==' ') {
 // use keys '1'-'3' to toggle display
 if(key=='1') showVoronoi=!showVoronoi;
 if(key=='2') showDelaunay=!showDelaunay;
 if(key=='3') showHull=!showHull;

void mouseMoved() {

if(myRegions==null) return;

//adding new points:
//void mousePressed() {
//  float [][] tmp=new float [1][2];
//  tmp [0][0]=mouseX;
//  tmp [0][1] = mouseY;
//  points [0] = tmp [0];
//  redraw();

Mesh Tab:

Voronoi myVoronoi;
Delaunay myDelaunay;
Hull myHull;

float[][] myEdges;
MPolygon myRegions[],myHullRegion;
int col[];

float startX,startY,endX,endY;
float[][] regionCoordinates;

boolean showVoronoi=true;
boolean showDelaunay=false;
boolean showHull=false;

void drawMesh(){
  if(myRegions==null) return;
 if(showVoronoi) {
   for(int i=1; i<myRegions.length; i++) {
     regionCoordinates = myRegions[i].getCoords();
     myRegions[i].draw(this); // draw this shape
 // draw Voronoi as lines
 if(showDelaunay) {
   for(int i=0; i<myEdges.length; i++) {
     startX = myEdges[i][0];
     startY = myEdges[i][1];
     endX = myEdges[i][2];
     endY = myEdges[i][3];
     line(startX, startY, endX, endY);
 // draw Hull in semi-transparent yellow
 if(showHull) {
   fill(255,255,0, 150);

void initMesh() {
 if(points==null) initPoints();
 int oldlength=0;
 if(myRegions!=null) oldlength=myRegions.length;

 myVoronoi = new Voronoi( points );
 myHull = new Hull( points );
 myDelaunay = new Delaunay( points );

 myRegions = myVoronoi.getRegions();
 myHullRegion = myHull.getRegion();
 myEdges = myDelaunay.getEdges();

 if(oldlength!=myRegions.length) {
   col=new int[myRegions.length];
   for(int i=0; i<myRegions.length; i++) {
     float prob=random(100);
     if(prob>60) col[i]=color(random(30,100));    
     else col[i]=color(random(200,255));  

particles tab:

float[][] points;
float[][] vel;
int searchDist;

PVector v1, v2;
//xPosition = points;
//yPosition = points;

void initPoints() {
   points = new float[100][2];
   vel = new float[100][2];

 for(int i=0; i<points.length; i++) {
   points[i][0] = random(width); // first point, x
   points[i][1] = random(height); // first point, y
   for(int i=0; i<vel.length; i++) {
   vel[i][0] = random(-2,2); // first point, x
   vel[i][1] = random(-2,2); // first point, y

void movePoints(){
    for(int i=0; i<points.length; i++) {
   points[i][0] +=vel[i][0]; // first point, x
   points[i][1] +=vel[i][1]; // first point, y

//move particles in smaller regions faster - over time- this is where i //get lost:
void moveFaster(PVector v1, PVector v2){
 PVector v1 = new PVector (random (100));
 PVector v2 = new PVector (random (100,200));
Re: Lee Byron's library Modification
Reply #1 - May 31st, 2010, 10:42am
I've downloaded the library (by downloading the demo at processingblogs) and looked at the source code a bit.  I added a drawPoints() method
void drawPoints() {
for (int i = 0; i < points.length; ++i) {
ellipse(points[i][0], points[i][1], 5, 5);

and called it after drawMesh() so I could see the points and understand what was going on a little better.

So, each point gets its own region, a polygon, and you want the points with smaller polygons to move faster.  Assuming you can get the vertices of a point's polygon (I'm guessing this is what the getEdges() method is for?) then all you need is a formula to calculate the area of a polygon from the coordinates of its vertices, and then scale the velocity of the point by the area.

I don't know what that formula would be, but I think that's the general idea.

Re: Lee Byron's library Modification
Reply #2 - Jun 4th, 2010, 7:24am
thank you, will try this now, Smiley
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