[visionegg] Re: screen position and graphics artifacts

  • From: Adam Light <aclight@xxxxxxxxx>
  • To: visionegg@xxxxxxxxxxxxx
  • Date: Mon, 7 Nov 2005 12:02:28 -0600

On 11/4/05, Andrew Straw <astraw@xxxxxxxxxxx> wrote:
>
>
> The screen position is determined automatically by the OS, I think. SDL
> (which is wrapped by pygame, which is wrapped by the Vision Egg) has
> some environment variables which are supposed to allow specification of
> screen position. see:
>
> //www.freelists.org/archives/visionegg/08-2003/msg00000.html
>
> Unfortunately, I think these environment variables aren't "officially
> supported" in SDL, and thus are subject to future non inclusion. (In
> fact, a recent build of pygame/SDL on Windows XP seems to ignore them,
> which I was planning on following up... Wait, it looks like it's
> discussed here:
> http://www.devolution.com/pipermail/sdl/2005-April/068395.html )


I tried the lines mentioned in the first link:

import os
os.environ['SDL_VIDEO_WINDOW_POS']="0,0"

and those worked perfectly.  My pygame version is 1.7.1release, so
perhaps it's older and thus still allows for this environment
variable.




> This is the well-known 'tearing' artifact. Googling that should give you
> a better idea of what the problem is. You can either try to fix it by
> clicking the "sync buffer swaps to vertical retrace" button on the
> Vision Egg initial GUI popup window, or by forcing this (often called
> "VSync") in your video drivers. If you need further help, let us know,
> and be sure to specify your OS and video card.


I did have the "sync buffer swaps to vertical retrace" option checked, but I
had to force the setting in my graphics card options (NVidia Quadro FX 1300
on WinXP).

Thanks for your help
Adam

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