[PyQt] max texture size for QGLWidget.bindTexture?

[Brian Parma]

David Boddie wrote:
> On Wed Sep 10 02:11:47 BST 2008, Brian Parma wrote:
>
>   
>> Ok, so I stripped down the program a little to make it into something of
>> a demonstration of the problem.
>> I'm running this on an Asus s5n laptop with XP Pro (SP3).  The graphics
>> controller is an "Intel 82852/82855 GM/GME" 6.14.10.3865. (yea it's a
>> little old)
>> PyQt 4.4.3, PyOpenGL 3.0.0b5
>>     
>
> That's interesting. I tried it with PyQt 4.3.0 and Qt 4.3.2 on Linux with
> an Intel 82845G chipset and I don't see any problems with the textures
> themselves, even when they are 1024 pixels wide.
>
>   
>> I haven't tried using OpenGL's texture loading functions, I'm not real
>> experienced with OpenGL programming (this is my first gl program) so I
>> have just been using PyQt4's QGLWidget's bindTexture, and passing it a
>> QPixmap.scaled.
>>     
>
> OK. It looks pretty good for your first OpenGL program. :-)
>
>   
Thanks, this is why I love python so much, it's so much easier to learn 
new tricks :)
>> In the program, I made it so pressing 'S' will prompt for a new width to
>> scale too, entering 640 works fine, but anything above that causes the
>> weird behavior (on this computer).  What is really strange is that
>> scaling the image to 641 looks the same as scaling it to 1024, and it
>> doesn't change again until you scale over 1024.
>>     
>
> Can you post a screenshot somewhere? The only visual artifact that I could
> see was due to clipping when zooming in too close to the cube, but I don't
> think that's related to your problem.
>
> David
> _______________________________________________
> PyQt mailing list    PyQt at riverbankcomputing.com
> http://www.riverbankcomputing.com/mailman/listinfo/pyqt
> ------------------------------------------------------------------------
Ok, here is a quick screencap I took with the cube rotated a little.  
This is scaled to 640 and displays normally:
http://picasaweb.google.com/execrable/Pub#5244624911032284418

This one is scaled to 1024 (looks the same as 641):
http://picasaweb.google.com/execrable/Pub#5244624910636885122

Other than the obvious new window (it takes a new screenshot each time 
it is rescaled).  The strange effect appears at the top of the texture.  
Basically what happens is a stripe of the texture disappears and is 
replaced by something random (mostly white in the picture).  This is the 
weird part though, it is not always white.  Yesturday it was displaying 
parts of a 3D scene that were previously rendered in a different 
(pyqt-opengl) program, like it was using left-overs from the buffer or 
something weird like that.

If I go even bigger, the stripe across the top gets bigger, and theres a 
stripe down the right side as well.  I don't have a screenshot with me 
and my laptop is at work, so I can't produce one until tomorrow.

Also this runs fine on my desktop at home (I can go all the way up to 
the 8192 that glGetInteger returns), so maybe it is a driver issue?  
Anyway, thanks for the help so far, this is fun stuff!