From: elvenforst AT aol DOT com (ElvenForst)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Allegro and VESA 2.0
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Date: 17 Sep 1998 16:29:29 GMT
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Message-ID: <19980917122929.27796.00000443@ng153.aol.com>
To: djgpp AT delorie DOT com
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>Hmmm. Clearing the frame before the video card can switch to the new one...?

(In VESA 2.0...)

No, I don't think that's it.  I'm clearing the memory bitmap, drawing onto it
and then blitting the memory bitmap to the screen.  The screen itself is never
cleared, just copied over...
>> The elements that are
>> drawn _early_ are solid and stable, but the parts of the screen that are
>> drawn_later_ are flickery and unstable.

It's almost as if the drawing functions (mostly blitting, rle and compiled
sprites) return before they've done the job, and complete it in the background
while the program moves on.  This resulting in the image not being completely
finished when the buffer is copied to the screen.  Also, there seems to be some
sort of wierdness with this and the sync (or lack thereof) with the vertical
retrace.

Does my hypothisis make any sense?  I can't figure it out on my own because I
don't know exactly what vesa is or how it works, as opposed to a "normal" video
mode like 13h.

Thanks,
Richard Ellwood