Mesh Library - Voronoi Issue - Processing Forum

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dusker1

Mesh Library - Voronoi Issue

in Contributed Library Questions • 2 years ago

This is the image I get. I'll give you a breakdown of what I'm doing.

- Exporting Voronoi Coordinates

- Importing coordinates to make new points.

- Upon re-importing, I've made it so there are no duplicated points using a set.

Problem:

- (Degrees of this problem range from a few cells to a lot) I lose areas of the Voronoi to nothingness

when I used the fill(??) function.

- Why do these black spaces appear? Anyone else run into this issue?

- The skeleton of the Voronoi appears to be fine when I don't use the fill(?,?,?) function.

Replies(9)

cedrickie..

Re: Mesh Library - Voronoi Issue

2 years ago

hard to answer without your code i guess. but sounds like it isnt a big problem.

dusker1

Re: Mesh Library - Voronoi Issue

2 years ago

//-----------Where I get my points from ------------------\\\\\\\\\\
for(int c=0;c<coordinates.length;c++)
{
OUTPUT.println(coordinates[c][0] + "," + coordinates[c][1] + "," + p + "," + "Coordinate");
xy = new PVector(coordinates[c][0],coordinates[c][1]);
if(!set.contains(xy))
{
set.add(xy);
}
}

/////---------------Where I add the points to a float[][] and create the second Voronoi--------\\\\
void setToArray()
{
float[][] uniqueCoords = new float[set.size()][2];
PVector[] pvArray = (PVector[])set.toArray(new PVector[set.size()]);
for(int p=0;p<set.size();p++)
{
float x = pvArray[p].x;
float y = pvArray[p].y;
uniqueCoords[p][0] = x;
uniqueCoords[p][1] = y;
}
secondVoronoi = new Voronoi(uniqueCoords);
secondRegions = secondVoronoi.getRegions();
drawRegions(secondVoronoi,secondRegions,uniqueCoords);
}

void drawRegions(Voronoi voronoi, MPolygon[] regions, float[][] points2)
{
regions = voronoi.getRegions();
float[][] coords;
for(int i=0; i<regions.length; i++)
{
coords = regions[i].getCoords();
strokeWeight(2);
stroke(0,255,0);
regions[i].draw(this);
fill(0,0,0);
}
}

This shows the correct outlines of the regions, however When i apply fill anywhere It ends up having the complete black spaces that don't seem to contain the regions anymore. With a complete black fill (fill(0,0,0)) and outlines on you can tell that there are gaps between voronoi's.

I have quite a bit of code behind this, so I hope the above snippets help.

dusker1

Re: Mesh Library - Voronoi Issue

2 years ago

Keep in mind these are 2 different generated Voronoi's, but I'm just displaying the difference between a filled and not filled voronoi, how the regions display properly when not filled.

With fill on:

Without the fill() function:

rbrauer

Re: Mesh Library - Voronoi Issue

2 years ago

In the last snippet, what is the for loop on line 15 for? Maybe try putting fill(0) around line 10.

dusker1

Re: Mesh Library - Voronoi Issue

2 years ago

The last for loop contained some redundant information, should have just edited it out. I tried putting it up above there and it colored a few regions but didn't color all of them. I took it out to avoid further confusion.

anchnk

Re: Mesh Library - Voronoi Issue

2 years ago

I think that your problem isn't really related to the fill() function.
Even if it seems to be obvious looking at your pictures.
But more on the way you designed your algorithm.

It's not easy to help without the full sketch but i think the way you call drawRegions might arise problems.
For example, you call secondVoronoi.getRegions() twice and the third parameter is meaningless in your function.
I'd focus on that one but again not easy to help if we couldn't give it a try.

dusker1

Re: Mesh Library - Voronoi Issue

2 years ago

Thanks, well points is actually used for something else but I can comment all of that out and the problem still arises. Thanks for the heads up on the double getRegions I reduced that to 1 but it still gives me the result.

I'm a bit perplexed because I can draw the boundaries of each region just fine without a fill(). Once I call the fill function it's as if some of the regions get eliminated.

dusker1

Re: Mesh Library - Voronoi Issue

2 years ago

This is a simplified Version of what I've been doing. Hope this helps!

import megamu.mesh.*;
float[][] points;
int numPoints = 20;
float h = 100;
float l = 115.47;
float maxDistance = 50;
Voronoi myVoronoi;
size(1280,768);
background(200,200,200);
points = new float[numPoints][2];
float walkX = width/2;
float walkY = height/2;
float varX = width/20;
float varY = height/20;
float tempX;
float tempY;
float distanceCheck;
for(int i = 0; i<numPoints; i++)
{
if( i <= numPoints)
{
tempX = walkX + random(-varX, varX);
tempY = walkY + random(-varY, varY);
if(tempX > width && tempX > height || tempX > width || tempX > height || tempX < 0)
{
i--;
}
else
{
points[i][0] = tempX;
walkX = points[i][0];
}
if(tempY > width && tempY > height || tempY > width || tempY > height || tempY < 0)
{
i--;
}
else
{
points[i][1] = tempY;
walkY = points[i][1];
}
}
}
myVoronoi = new Voronoi(points);
MPolygon[] myRegions = myVoronoi.getRegions();
for(int i=0; i<myRegions.length; i++)
{
stroke(255,0,0);
strokeWeight(2);
myRegions[i].draw(this);
fill(0);
}
Set set = new HashSet();
ArrayList vectorArrayList = new ArrayList();
for(int p=0;p<myRegions.length;p++)
{
float[][] coordPoints = myRegions[p].getCoords();
for(int c=0;c<coordPoints.length;c++)
{
PVector xy = new PVector(coordPoints[c][0],coordPoints[c][1]);
if(!set.contains(xy))
{
vectorArrayList.add(xy);
set.add(xy);
}
}
}
for(int t=0;t<points.length;t++)
{
PVector pPoints;
pPoints = new PVector(points[t][0],points[t][1]);
vectorArrayList.add(pPoints);
}
float[][] uniqueCoords = new float[vectorArrayList.size()][2];
for(int r=0;r<vectorArrayList.size();r++)
{
PVector xyPos = (PVector)vectorArrayList.get(r);
float x = xyPos.x;
float y = xyPos.y;
uniqueCoords[r][0] = x;
uniqueCoords[r][1] = y;
}
Voronoi secondVoronoi = new Voronoi(uniqueCoords);
MPolygon[] newRegions;
newRegions = secondVoronoi.getRegions();
for(int i=0; i<newRegions.length; i++)
{
stroke(255,0,0);
strokeWeight(2);
newRegions[i].draw(this);
fill(0);
}

The result is a broken up Voronoi, with spaces in between cells. Little confused by these open areas as they are don't seem to be regions.

If you keep running it, sometimes it works, but more often than not it is a broken up Voronoi with separated cells.

In the above example I provided, even when you switch between fill and strokes not all the regions are drawn!

dusker1

Re: Mesh Library - Voronoi Issue

2 years ago

Figured out the problem. For some reason it was causing a problem when points existed outside of the screen.

Solution:

if(!set.contains(xy) && x > 0 && x < width && y > 0 && y < height)
{
vectorArrayList.add(xy);
set.add(xy);
}

Fixes the problem like a charm, thanks for the tips and such. Helped steer me in the right direction.

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