Path: utzoo!attcan!uunet!wuarchive!julius.cs.uiuc.edu!apple!metaphor!neuromancer!djh
From: djh@neuromancer.metaphor.com (Dallas J. Hodgson)
Newsgroups: comp.sys.amiga.tech
Subject: Re: How fast is the BltBitMap() routine?  (Anim. speed & redraw)
Message-ID: <1437@metaphor.Metaphor.COM>
Date: 19 Sep 90 19:04:32 GMT
References: <11825@uservx.afwl.af.mil>
Sender: news@metaphor.Metaphor.COM
Reply-To: djh@neuromancer.metaphor.com (Dallas J. Hodgson)
Organization: Metaphor Computer Systems, Mountain View, CA
Lines: 33

In article <11825@uservx.afwl.af.mil> GALETTI@uservx.afwl.af.mil writes:
>How fast is the graphics.lib "BltBitMap()" routine?  It seems to me that
>setting up the blitter for a copy shouldn't take all that much time. 
>
>However, if you have two routines that copy the same amount of area from one
>bitmap to another, and one of the routines does the copy with one blit while 
>the other routine does the copy with two half-sized blits, the two half-sized 
>blits take noticeably longer than the single copy.
>
>I am using BltBitMap() to do the copies.  For those of you who have experience
>writing your own blitter routines, do you think it would it be worth my while 
>to write a replacement for BltBitMap()?  How significant would the speedup be?
>
>Thank you in advance,
>
>-Ralph

What timing, I was just experimenting with this last night. For the
animation I was working on, I tried this two ways: Using BltBitMap, and
using a near-equivalent routine which had CopyMemQuick at its core. The
CopyMemQuick routine was always significantly faster, even with FAST RAM and
caching turned off on my A-3000.

This may not hold true for 16-bit Amigas. I plan to do an A-1000 benchmark
tonight.
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| Dallas J. Hodgson               |     "This here's the wattle,             |
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