NetNews Offline 2/NetNews Offline Volume 2.iso/news/comp/sys/amiga/programmer/4830

Internet Message Format | 1996-08-05 | 3.4 KB

Path: informatik.tu-muenchen.de!fischerj
From: [e-mail] (Juergen "Rally" Fischer)
Newsgroups: comp.sys.amiga.programmer,comp.sys.amiga.advocacy,comp.os.ms-windows.advocacy
Subject: Re: intuition inefficient ?
Date: 5 Mar 1996 15:57:04 GMT
Organization: Technische Universitaet Muenchen, Germany
Distribution: world
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In article <4h7l0l$[e-mail]>, [e-mail] (Stephan Schaem) writes:
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|> Xref: informatik.tu-muenchen.de comp.sys.amiga.programmer:88285 comp.sys.amiga.advocacy:152941 comp.os.ms-windows.advocacy:134518
|>
|> Juergen "Rally" Fischer ([e-mail]) wrote:
|> : Stephan Schaem ([e-mail]) wrote:
|> : : Juergen "Rally" Fischer ([e-mail]) wrote:
|>
|> : :  I dont know PC HW , but Dbuffer is what I would go for... BTW I read
|> : only tripple buffering makes full use of cpu.
|>
|>  Ok, but this was reguarding a waitfof methode . but hey, if the card
|>  as enought mem for 3 buffer and support seting video mem start and
|>  allow vblank interupt I would go for that. I would go with even more
yep, that's wwhat you need.

|>  if the video HW could work in parallel to prepare a 'blank page'.
|>  (BTW: thats the senario on the amiga if you draw 3d objects on a
|>  blitter backdround.)
|>
|> : :  that the 'majority' of amiga nowdays dont have a vbi anymore :)
|> : :  Well they have the native video one, but since its not used it mean
|> : :  nothing.
|> : Using the AmigaOS3.0 routines does it for both AGA & gfx-cards.
|>
|>  I read here that the routine use diferent sync then the gfx card.
|>  like the card run at 72hz, the sync you will get will be 50 or
|>  whatever your native chipset is running at.

Afaik OS-buffering routines do work. They do work on Amiga. If they
don't work after you plugged in the gfx-card, it's not AmigaOS but
a buggy driver.

|>
|> : :  The VBL mean nada for splitfree anim, you can as well use a timmer
|> : :  interupt derived from the video mode timing.
|>
|> : On AmigaOS, yes (but you don't need it as gfxlib already got it).
|> : On PC AFAIK only under DOS.
|>
|>  On amiga OS or ANY OS you cannot get splitfree anim with a vbeam sync!

I was refering to the fact hacking the timer might conflict on other
PC-OSes than DOS.

|>  you need dbuffer MINIMUM.

you need either 2 video buffers or local bus, which can copy faster
than beam.

BUT: you need 3 buffers if you want to make max usage of cpu.
Or, on a VLB, you need a vblank-interrupt to invoke the copy to
a single vram buffer.

|>
|>  Stephan
------------------------------------------------------------------------
   [e-mail] (Juergen "Rally" Fischer)   =:)