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From: rwallace@vax1.tcd.ie
Newsgroups: comp.sys.amiga
Subject: Re: Graphics.library (was transputer board)
Message-ID: <5849.26208c08@vax1.tcd.ie>
Date: 9 Apr 90 13:20:08 GMT
References: <02602.AA02602@sosaria.imp.com> <8612@hubcap.clemson.edu> <PORTUESI.90Apr4111348@tweezers.esd.sgi.com> <5845.261cc9b7@vax1.tcd.ie> <28715@cup.portal.com>
Organization: Computer Laboratory, Trinity College Dublin
Lines: 28

In article <28715@cup.portal.com>, phorgan@cup.portal.com (Patrick John Horgan) writes:
> Russell Wallace said:
> 
> |All graphics software that needs to do anything FAST (i.e. animation) accesses
> |the video RAM and probably the blitter & copper directly because the graphics
> |library routines are much too inefficient.
> 
> I used to think this too.... 
> ... Graphics is a bit of a specialty with me and I was able to recognize
> the algorithms used.  They really use efficient algorithms.  You're right
> that there is a lot of overhead, but it's not because the code is bad, or
> the algorithms inefficient.  The real problem is that the routines must be
> general purpose.  The routines must work in a multi-window environment.  This
> means that you have a damage-list and complex clipping must be done for 
> almost any graphics call.  This takes time.  The clipping routines are 
> efficient though:)  I was only able to speed up line-drawing using the blitter
> directly by assuming that my window would always be on top.

To be sure, given that you have to do stuff with multiple windows, menus etc.
the graphics library routines aren't that inefficient. The problem is the same
routines have to be used even if you've opened your own custom screen, are
using no menus and could just transfer everything straight into video RAM.
There should be a separate set of routines for that and given that there aren't
and that you need speed, you have to do things yourself.

"To summarize the summary of the summary: people are a problem"
Russell Wallace, Trinity College, Dublin
rwallace@vax1.tcd.ie