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From: tarolli@riva.esd.sgi.com (Gary Tarolli)
Newsgroups: comp.sys.sgi
Subject: Re: DGL server for SUN or TAAC? - plus a question...
Summary: DGL explanation
Message-ID: <47691@sgi.sgi.com>
Date: 8 Jan 90 17:07:31 GMT
References: <1990Jan7.174208.27895@jarvis.csri.toronto.edu> <50204@bu.edu.bu.edu>
Sender: tarolli@riva.esd.sgi.com
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Organization: Silicon Graphics, Inc., Mountain View, CA
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In article <50204@bu.edu.bu.edu>, tjh@ouzo.bu.edu (Tim Hall) writes:
> In article <1990Jan7.174208.27895@jarvis.csri.toronto.edu> lansd@dgp.toronto.edu (Robert Lansdale) writes:
> 
> Awhile ago I posted a question about DGL on SUN's and got replies from
> people suprised that the DGL ran on SUN's.  People also seemed
> confused about what the DGL does.  As I understand it, the DGL only
> uses the SGI geometry engine, but it allows you to send commands to
> it from remote machines.  So, a dgl routine won't use a TAAC (or
> any other non-SGI engine/display) to compute or display an image on.
> 
> The question...
> 
> When using the DGL and making a display list (graphical object) does
> it save the display list on the server or the client?
> 

To answer your last question first, the DGL saves the display list on the
server, so that calling the display list costs the client very little and
results in very little network traffic.  

The DGL is basically a custom Remote Procedure Call (RPC) library for the
GL.  Its the equivalent of the X client library.  It allows you to call the
GL from a client machine by sending RPC tokens over a network to a server.
Almost all GL routines get token'ized and sent to the server for execution.
Almost no code executes on the client except for packing these tokens into
a buffer and writing the buffer occasionally.

The client library is portable and so far has been ported to SUN, VAX/VMS,
VAX/BSD, Convex, Alliant, IBM, and Cray client hosts.  The server only runs
on SGI graphic workstations.
--
						Gary Tarolli