View Full Version : Weird Viewport problem

04-22-2002, 06:59 AM
Hi, I'm currently testing an OpenGL viewer I made on a PC with a 8mg Card ( An ATI XL or something like that ).

There seems to be a problem when setting the glViewport. The opengl is drawing only part of the viewport, and the other part isn't drawed at all BUT, it's being cleared by the glClear command. WTF is going on? Not enough VRAM?? I'm using double buffer pixel format also..

Does anyone ever had something like that?


04-22-2002, 10:57 AM

do you have the source for this tool?? Take a look at the drawing func, maybe there is something like a scissor test, or the other possibility is you might be standing partly inside the model.


04-22-2002, 11:09 AM
how large a portion of the viewport isn't being drawn? I'm having a similar problem where a band down the left edge of the viewport gets cleared but no geometry will draw there... only I'm having the problem on a GeForce3, so I don't think it's a card issue...

Currently I'm suspecting my viewport resizing code, but the fact that the area gets cleared confuses me a lot.

Does glClear() not restrict istself to the viewport for some reason?

04-22-2002, 11:31 AM
I am aware you mention "left" side instead of "right" side and also glClear works.
But I still want to mention this infamous bug:

04-22-2002, 12:28 PM
Ah, yeah... it's not that one (at least for me)... good info though...

04-23-2002, 10:42 AM
Hey, I ended up solving my problem by ugrading my drivers - the ones that shipped with my card (Hercules 3D Prophet III - GeForce 3 based) seemed to be buggy.

I don't know if a driver upgrade is an option for your card, but you might give it a shot.