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Index › Programming Questions & Help › Programs › Getting a clean render with TRIANGLE_STRIP
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Getting a clean render with TRIANGLE_STRIP (Read 480 times)
leafcutter
Getting a clean render with TRIANGLE_STRIP
Dec 16th, 2008, 12:31am  
I notice that when I use TRIANGLE_STRIP and try and get rid of the stroke by setting the weight to 0 or by setting the colour to be equal to the fill colour I can still see small sections where the shapes are not quite joining up and the background is visible - like cracks I suppose.

It does not happen when I don't use smooth.

this code demonstrates the problem:

size(500, 500);
background(204);
smooth();
//noStroke();
fill(0);
stroke(0);

int x = width/2;
int y = height/2;
int outerRad = 248;
int innerRad = 50;
float px = 0, py = 0, angle = 0;
float pts = 36;
float rot = 360.0/pts;

beginShape(TRIANGLE_STRIP);
for (int i = 0; i < pts; i++) {
 px = x + cos(radians(angle))*outerRad;
 py = y + sin(radians(angle))*outerRad;
 angle += rot;
 vertex(px, py);
 px = x + cos(radians(angle))*innerRad;
 py = y + sin(radians(angle))*innerRad;
 vertex(px, py);
 angle += rot;
}
endShape();

I'm very new to Processing so I may well be doing something wrong. Is there a way to use smooth and to get no cracks?

Processing 1.01 on Mac

Thanks and best,

John.
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rebirth
Re: Getting a clean render with TRIANGLE_STRIP
Reply #1 - Dec 16th, 2008, 8:51am  
i don't see exactly what you're referring too. why not take a screen shot and indicate the problem? it may very well look different on your system.
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leafcutter
Re: Getting a clean render with TRIANGLE_STRIP
Reply #2 - Dec 16th, 2008, 6:19pm  
Good idea,

There is a screen shot here - the problem is subtle but occurs inside the red oval.

http://tinyurl.com/55n5l4

thanks,

John
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rebirth
Re: Getting a clean render with TRIANGLE_STRIP
Reply #3 - Dec 16th, 2008, 6:56pm  
here's a simple solution: change for (int i = 0; i < pts; i++) to for (int i = 0; i <= pts; i++).
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JohnG
Re: Getting a clean render with TRIANGLE_STRIP
Reply #4 - Dec 16th, 2008, 7:06pm  
Change for "i < pts;" in your for loop to "i <= pts;"
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leafcutter
Re: Getting a clean render with TRIANGLE_STRIP
Reply #5 - Dec 16th, 2008, 10:10pm  
Ahh, thank you both. That was simple!

So much to learn....

best,

John.
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