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ortho() for 2D? (Read 554 times)
narain
ortho() for 2D?
May 29th, 2006, 6:48pm  
Is there a way to set the coordinate system in a 2D sketch by specifying the X and Y ranges? I have a collection of nodes with varying positions in my sketch and I want to be able to shift and zoom the window to show them all. I know I can do that with translate() and scale(), but it seems useful enough to have a dedicated function for. ortho() does exactly this in 3D, but is there a purely 2D version? And if not, shouldn't there be?
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movax
Re: ortho() for 2D?
Reply #1 - Jun 8th, 2006, 8:45pm  
Sure.   The window pixels can relate to your 'world coordinates' any way you want by using 2 variables, lets call them rangex and rangey.

Lets say you want the center of the window to be 0,0 and that the window can cover any sized rectangle of your world coordinates. So window's x could cover [-1,1] (rangex=2) or [-3000,3000] (rangex=6000), etc.

drawnode(float nodex, float nodey){  
int screenx,screeny;

screenx=(nodex/rangex) * width +  (width/2);
screenx=(nodey/rangey) * height +  (height/2);

ellipse(screenx, screeny,10,10);  //draw node
 
}

This is coordinate mapping.  To add shifting is not much harder.
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