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Index › Programming Questions & Help › Syntax Questions › Use BW image map as source for creation
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Use BW image map as source for creation (Read 529 times)
Cedric
Use BW image map as source for creation
Dec 6th, 2008, 12:15am  
Just to explain it really simple:  i want a black and white image to use as source for the creation of objects. Lets say, i have a 300x300 sketch and a 300x300 BW gif in my data folder. Now i want to draw circles exactly at the point where the source map is black.

I couldnt find some good excamples but i know they exist. Alot of people use this to recreat pictures and also color the shapes they draw corresponding to the image...

Thanks for your help!
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V
Re: Use BW image map as source for creation
Reply #1 - Dec 6th, 2008, 1:29pm  
you loop for all the pixels of the image and when you find a black pixel you draw a circle

ArrayList circlePos;

circlePos = new ArrayList();  // ill keep a list of all the black pixel's position in an array

int jidx = 0;
for( int j=0; j<img.height; j++ )
{
 jidx = j * img.width
 for( int i=0; i<img.width; i++ )
 {
   // if current pixel is black, save position to our array
   if( red(img.pixels[jidx+i]) == 0 )
     circlePos.add( new Vector3( i, j, 0 );
 }
}

now you have an array of points. those points are every black pixel you have in your image. just go thru the array and draw a circle at everypoint.
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Victor Martins | www.pixelnerve.com/v
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Cedric
Re: Use BW image map as source for creation
Reply #2 - Dec 6th, 2008, 3:38pm  
Thank you!
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PhiLho 
Re: Use BW image map as source for creation
Reply #3 - Dec 6th, 2008, 7:02pm  
Two little improvements: you can increase the increment of the loops, to be equal to the diameter of the circles, so spacing them a bit.
And it is enough to test if pixels[n] isn't zero (or alpha value?), might be faster than extracting the red component.
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V
Re: Use BW image map as source for creation
Reply #4 - Dec 6th, 2008, 7:14pm  
phillo, thanks for ur sharp eye =)
but for a simple static image this would be pre-calc'ed =)
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Victor Martins | www.pixelnerve.com/v
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Cedric
Re: Use BW image map as source for creation
Reply #5 - Dec 6th, 2008, 7:26pm  
seems to work... thanks again to both of you...

first tests...

http://www.dec32.de/public/p5img1.jpg
http://www.dec32.de/public/p5img2.jpg
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jegb
Re: Use BW image map as source for creation
Reply #6 - Dec 9th, 2008, 7:20pm  
Hi!
I dont know if your definition of 3D is like this, but this height map I did (emulating some Scriptographer effect) may help.
http://www.flickr.com/photos/72209952@N00/2218491686/
the script is attached there, but feel free to post back code if you have issues.

jegb
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