When you say reporogramming the timer won't work under Window's, do you mean running the program (I assume we're talking DOS here) under Windows, or writing an actual Window's program that modifies the timer? My DOS game reprograms the timer, and it runs fine under Windows.
Rock
If you use the screen and 2 buffers you can
send the triple buffer to the double buffer.
Place your mousecursor (and other objects?) on the double buffer and send it to the screen after vsync();
(call some sort of mousexy function before you'll place the cursor)
Hope that helped.
. Windows allow timer reprogramming, but only on a little small amounts (coz win uses timer itself). But reprogramming it, for example, to 70Hz may cause a little problems.The 1st way will slow down whole code, but i
remember another way: hooking on video adapter interrupt. I've tryed to implement this some time ago (for hicolor emulation in 13h mode), but my code doesn't worked.
bosjoh: copying from first buffer to second and then to memory is VERY slow.
thanx for your replyes
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FlyFire/CodeX
http://codexorg.webjump.com
Be that right or wrong, I can say that my DOS game sets the timer to 600Hz, and like I said it runs fine under Win95 and real DOS.
If the only problem with bosjoh's suggestion is speed, then why don't you draw the image(s) to a video back surface and use page-flipping, which takes about 0% overhead.
I've never heard of a vsync interrupt, except on other systems like the Amiga. If there were such a thing, wouldn't it be used by everyone instead of manually polling for the vsync? Where did you see this info?
Rock
You must have heard about installing a mouse interrupt handler under int 33h. I really don't recommend this since when I used that I'd got thrown out's without a reason.
Only 1 time the compiler gave a stack overflow error.
Drawing directly to back video surface is very slow, especially if you drawing transparent surfaces.
bosjoh: i've seen an article somewere, where were described how to write your own mouse handler (i.e. catch hardware interrupts from mouse by yourself). If i remember currectly, it was on http://www.wotsit.org/ under hardware section.
Ok guys, thanx for your responses, i think i've found solution (specific, and for my need only, based on bosjoh's idea). I'll draw mouse cursor when PageFlip() function will be called. This way i can handle back and double buffers flipping.
I think i've found solution for my need.
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FlyFire/CodeX
http://codexorg.webjump.com
)Is there any other ways or ideas?
Thanx
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FlyFire/CodeX
http://codexorg.webjump.com
My DOS timer will run up to around 100KHz under true DOS 6.22, but only about 1Khz under Win95, and not reliably at all under NT. Obviously something is going on in those environments.
Rock
