Hi Adeola,

OpenGL must be expecting a certain "packing" but your image data is 
packed differently. You have (at least) two options: 1) alter your numpy 
arrays to match the packing of OpenGL. This can be done by creating an 
array with the appropriate .strides value. 2) alter OpenGL's idea of how 
the data is packed. For this, see "7. Watch Your Pixel Store Alignment" 
in http://www.opengl.org/resources/features/KilgardTechniques/oglpitfall/ 

-Andrew

Adeola Bannis wrote:
> Hi,
>
> I have a set of images I want to render with OpenGL, and I do this by
> doing some calculations, producing an array, then passing this array
> to OpenGL.  Here's the relevant OpenGL call, for reference:
>
> gluBuild2DMipmaps(GL_TEXTURE_2D, 1, image.shape[0], image.shape[1],
>                                                       GL_LUMINANCE, 
> GL_UNSIGNED_BYTE, flatImage)
>
> flatImage is just image as a flattened, contiguous numpy array... all
> that matters is that it contains the same values as in image.
>
> The problem is that passing my arrays to pylab.imshow() displays them
> exactly as they are meant to be, but in OpenGL they are 'twisted'.
> There is an offset that is _different_ for each picture that only
> seems to be resolved by replacing 'image.shape[0]' by
> 'image.shape[0]-5' or some other numbers that make the rows shorter.
> How is it that OpenGL does weird things with the row length but pylab
> is always happy?
>
> I can send pictures of the problem if it helps....
>
> Adeola
>
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