From: "Tim B" Newsgroups: comp.os.msdos.djgpp Subject: Still frustrated with mouse problem (actually a blitting prob) Lines: 35 X-Newsreader: Microsoft Outlook Express 4.72.3110.1 X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 Message-ID: <6A5W3.270$Up1.2636@newsfeed.slurp.net> Date: Tue, 9 Nov 1999 21:29:40 -0600 NNTP-Posting-Host: 207.112.213.15 X-Trace: newsfeed.slurp.net 942204290 207.112.213.15 (Tue, 09 Nov 1999 21:24:50 CDT) NNTP-Posting-Date: Tue, 09 Nov 1999 21:24:50 CDT To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Reply-To: djgpp AT delorie DOT com Okay, this is my second attempt at trying to find some help with this problem. I originally thought this was a problem with the mouse functions but after doing some tests I discovered the mouse droppings were only a symptom of the real problem which seems to be that images blitted from the screen (video memory) on occasion become slightly corrupted. That's why the mouse appeared to create extra random pixels because the image under the mouse was originally blitted from the screen. There doesn't seem to be any problem when blitting to the screen and the problem only seems to happen in the svga modes. In particular, if the image is blitted from a horizontal screen position that can be divided by 4 and any vertical position, the image is transferred accurately. However, if blitted from any other horizontal position the image sometimes becomes corrupted. The computer I'm currently using has a pc100 motherboard with a built in 3D AGP graphics adapter and a vesa compliant video bios. I've done the same tests with the program on my 486/66 which has a Trident 8900 and there is no problem. Blits can be done anywhere from the screen with no corruption which is of course what would be expected. I also originally thought this might be due to a buggy vesa bios but I don't seem to have this problem with other non-djgpp graphics programs I've used. This includes an extended dos program created with dos/4gw. So I'm beginning to think maybe this is a problem with DJGPP (I'm using v2.01). It seems questions are always encouraged, but it's pointless advice if they're never answered. So I'm asking again. Please, if anyone has ever come across this kind of thing or can suggest any possibilities for dealing with it. Is the problem in my graphics adapter? Is it in DJGPP? Is there a patch for it? Is it something I can fix myself?