Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga.advocacy Subject: Re: Blitter vs. 040 (was: Computer Architecture question Message-ID: <21645@cbmvax.commodore.com> Date: 16 May 91 15:06:06 GMT References: <1991May15.125954.1993@NCoast.ORG> Reply-To: daveh@cbmvax.commodore.com (Dave Haynie) Organization: Commodore, West Chester, PA Lines: 32 In article melling@cs.psu.edu (Michael D Mellinger) writes: >Yes, an 040 + blitter will be better than just an 040. I was trying >to get the point acrossed that animation is possible on the NeXT, not >as good as the Amiga, but it seems like 20 to 30fps is possible, >unless something else has been overlooked. Actually, one of the most important things for good looking animation is the capability to synchronize with your display frame. Double or N-Buffering makes this a no-brainer on Amiga, but technically, double buffering isn't a requirement for smooth animation. What is required, however, is a way to insure that the frame being displayed is never changed in the middle of a frame. This is much harder to coordinate if you don't have buffering capability, since it means the CPU must be otherwise kept out of the part of the frame that hasn't been displayed yet. Since the CPU can outrun the display in many systems, something as simple as a vertical retrace interrupt may work, assuming interrupt response latency is short enough. Bottom line, though, is that you need some hardware support for runtime animation, regardless of who's "doing" the animation in a system. And without good hardware support, the animation is going to be ugly (updates crossing the displayed raster are very noticable), less than optimal (fewer FPS than the hardware could support in ugly mode), or both. CPU speed is only a real minor factor in many cases; a C64 can do simple, smooth animation. BTW, I really know nothing about the NeXT display hardware and what's possible with it. Could be they're set up for the possibility of good animation, could be they're not. -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "That's me in the corner, that's me in the spotlight" -R.E.M.