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Index › Programming Questions & Help › OpenGL and 3D Libraries › Get the result from a rotate
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Get the result from a rotate (Read 550 times)
knutEinar
Get the result from a rotate
Jan 8th, 2008, 4:03am  
Hello,
is there any way in Processing (or Java/OpenGL) I can get the result from an arbitrary rotation? To exemplify, let's say I have a vector (x, y, z) that I want to rotate around the y-axis. But instead of doing the rotation in a pushMatrix, I want to collect the result in an array so that I later can apply faces to a mesh. I've been digging for this info for a while now, and it seems to be possible to do this with java, but to try to understand the java docs and get some useful info from it is somewhat overwhelming to me  ...

I've been trying to achieve the same result using matrices, and it works to a certain point, but gives me some weird results as well. The simplest would really be if there were some function I could use to retrieve these results. Does this even make sense?

Skjaer
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mflux
Re: Get the result from a rotate
Reply #1 - Jan 9th, 2008, 2:58am  
Is this what you need?

http://processing.org/reference/modelX_.html

If I understand you correctly you're trying to do a rotation but then get where that rotation ends up being.

Or, you can manipulate rotations yourself doing atan2 for xy, then yz (something like that), that way you'll have the right vector of rotation.
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fluxhavoc  
taifunbrowser
Re: Get the result from a rotate
Reply #2 - Jan 9th, 2008, 4:56am  
Whhhhaaaaa??

but that's so USEFUL!

why aren't those 3 methods listed in the reference <_<?

edit: --... oh there they are.

Thanks! good info.
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knutEinar
Re: Get the result from a rotate
Reply #3 - Jan 9th, 2008, 5:35am  
mflux, you are my hero Smiley Why didn't I find this before? I even just read the whole book from Casey and Ben, and it was nothing there either! Ah, goodbye ugly matrices and impossible quaternions! There is still hope for the mathematically challenged among us!!

Thanks again mflux Cheesy
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mflux
Re: Get the result from a rotate
Reply #4 - Jan 9th, 2008, 10:39am  
np

Just FYI modelXYZ wasn't working as advertised, up until a few months ago where a bunch of us submitted work-arounds and Ben finally nailed it. Possibly the reason why it wasn't in the book.

~M
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fluxhavoc  
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