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From: larsen@ginger.princeton.edu (Michael Larsen)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Optimizing Copybits
Message-ID: <1694@idunno.Princeton.EDU>
Date: 7 Aug 90 23:57:10 GMT
References: <1990Aug2.223758.13691@murdoch.acc.Virginia.EDU> <KPHN70@cs.swarthmore.edu>
Sender: news@idunno.Princeton.EDU
Reply-To: larsen@ginger.Princeton.EDU (Michael Larsen)
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Organization: Princeton University
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In article <KPHN70@cs.swarthmore.edu> jackiw@cs.swarthmore.edu (Nick Jackiw) writes:
>mil@mendel.acc.Virginia.EDU (Maria I. Lasaga) writes:
] 
] We need to optimize the speed with which copybits places a complex
] image from an offscreen port to the screen.  
] 
>20K of data at 60hz?  I doubt you'll make it. My SE/30 can't do that in a
>tight display loop with major optimizations in place...

I don't know about CopyBits performance, but you should certainly be able 
to load video RAM faster than that by hand.  On my Mac II, it takes ~12 
msec to fill the screen in 1-bit mode (38K) from a buffer in memory.  So even
an SE ought to be able to copy 20K to video memory in no more than 2
screen refreshes.

						-Michael Larsen