Different Results between No Accel. and Full Accel.

I’m getting different results, actually bugs, between Full Acceleration and No Acceleration on my M$ win98 machine. For example, when I gluUnProject the results with no acceleration are correct but when I use full acceleration I get drastically wrong results.

Any ideas?

This is what the feature is for. It’s obviously a bug in the hardware driver. When you dial down to no acceleration you effectively use a ‘safe’ software OpenGL implementation.

Hi Dorbie,
Thanks for the confirmation; this is what I thought as there are other machines I tried and did not encounter the same results.

Is there a way to coerce No Accleration in an OpenGL app, even when the user chooses to Full Acceleration from the video settings?

Simply enumerate the available pixel formats and choose one that is not accelerated.

I posted some code enabling you to just do that a while ago. Search the forums for posts from me (use the Exact Name search, it’s faster !) with the keyword “software”.



Will do Eric!

Thanks for the info…


Just for reference:



Hi Eric,

Thanks for the reference! I’ll be giving this a go in a couple of days.

Again, many thanks.