Re: GLU NURBS precision

Chris Barker <[email protected]> Fri, 26 Oct 2012 17:28:55 -0800
Newsgroups gmane.comp.python.opengl.user
Message-ID <4265661263147110194@unknownmsgid>
Given OpenGL uses single precision- I'd use single (numpy.float32) for
your numpy arrays, too. One of the nice things about numpy.
-chb
On Oct 26, 2012, at 10:38 AM, "Mike C. Fletcher" <[email protected]> wrote:

> On 12-10-26 10:21 AM, Hugo Gagnon wrote:
>> Hello,
>>
>> I'm writing an application that uses GLU's NURBS capabilities.  I'm
>> passing double-precision numpy arrays to gluNurbsCurve and
>> gluNurbsSurface, which works fine, only that PyOpenGL seems to
>> automatically convert them to single-precision, which slows down my app.
>>  Does this conversion have to do with PyOpenGL or is it an OpenGL
>> limitation?  Is there any way around it?  other than having to keep
>> track of two arrays of different types around...
> The C-level function requires GLfloat * arrays (i.e. single precision).
> PyOpenGL, by default, will copy the array if the type is not compatible
> with the target function.  So the conversion is PyOpenGL, but if it
> didn't do it you'd get a garbage result (each half of your double
> interpreted as a float).
>
> HTH,
> Mike
>
> --
> ________________________________________________
>   Mike C. Fletcher
>   Designer, VR Plumber, Coder
>   http://www.vrplumber.com
>   http://blog.vrplumber.com
>
>
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