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Index › Programming Questions & Help › OpenGL and 3D Libraries › Unwanted holes in a shape
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Unwanted holes in a shape (Read 1033 times)
DieTapete
Unwanted holes in a shape
Dec 20th, 2009, 1:21pm  
Hi,

i created a 3d shape with beginshape but unfortunately there are some erros in it.
take a look at it: dl.dropbox.com/u/2409265/line-2318.png

what's the reason for this?
i use this code:
Code:

for (int q=0; q<NUM_PARTICLES; q++){
    for(int i=0; i<NUM_HAIRS; i++) {
	  beginShape();
	  if (i+1<NUM_HAIRS && q+1<NUM_PARTICLES){
	  VerletParticle p=(VerletParticle)hairs[i][q];    
	  vertex(p.x,p.y, p.z);
	  p=(VerletParticle)hairs[i+1][q];    
	  vertex(p.x,p.y, p.z);
	  p=(VerletParticle)hairs[i+1][q+1];    
	  vertex(p.x,p.y, p.z);
	  p=(VerletParticle)hairs[i][q+1];    
	  vertex(p.x,p.y, p.z);
	}
	    endShape();
    }
  }
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koogy
Re: Unwanted holes in a shape
Reply #1 - Dec 20th, 2009, 1:51pm  
> there are some erros in it.

you'll have to be clearer than this.
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DieTapete
Re: Unwanted holes in a shape
Reply #2 - Dec 21st, 2009, 1:38am  
If you take a look at the picture you can see some black triangles in the shape. They look quite interesting but I don't want them. Wink
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Quark
Re: Unwanted holes in a shape
Reply #3 - Dec 21st, 2009, 6:42am  
I must be going blind I can't see any black triangles in the image perhaps you might want to edit the picture to indicate where these are.
There are some visual effects due to the image resolution / level of detail and the angle you are viewing the shape.

You might try declaring the type of shape with
Code:
beginShape(QUADS);
rather than using the default value.
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DieTapete
Re: Unwanted holes in a shape
Reply #4 - Dec 21st, 2009, 6:55am  
Well you may not have seen the black triangles but you gave me the right hint! The holes are gone since I use QUADS. Thanks! Smiley

Looks much better now: dl.dropbox.com/u/2409265/line-0324.png

Another question: Is it possible to smooth the surface by calculating other normals?
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Quark
Re: Unwanted holes in a shape
Reply #5 - Dec 22nd, 2009, 6:44am  
Looking good.

Quote:
Is it possible to smooth the surface by calculating other normals?

In some areas you have very smooth color transitions between QUADS and in some it is noticeably different.
There are 3 ways to get the smooth color transitions
(1) using the fill() to set a fill color for  each vertex
(2) use normal for each vertex. Correctly calculated normals can be quite effective if you are using lights.
(3) a combination of (1) & (2)
To give a better answer it would be useful to see the code you now have between
Code:

beginShape(QUADS);

endShape(CLOSE)


Yes the CLOSE is useful if you are drawing it as wire frame so might as well include it.
Smiley
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