$Id: README,v 1.7 89/09/20 17:49:08 mbp Exp $

				 LGD

************************************************************************
*		Copyright (C) 1989 by Mark B. Phillips                 *
* 								       *
* Permission to use, copy, modify, and distribute this software and    *
* its documentation for any purpose and without fee is hereby granted, *
* provided that the above copyright notice appear in all copies and    *
* that both that copyright notice and this permission notice appear in *
* supporting documentation, and that the name of Mark B. Phillips or   *
* the University of Maryland not be used in advertising or publicity   *
* pertaining to distribution of the software without specific, written *
* prior permission.  This software is provided "as is" without express *
* or implied warranty.                                                 *
************************************************************************

			 GENERAL INFORMATION

This is LGD, a 3-dimensional vector graphics library for C programs.
The name LGD stands for "Logical Graphics Device", and is meant to
indicate the device independent nature of the LGD.  The general
philosophy of LGD is to provide an abstract 3-dimensional graphics
device in which an application program can create a "world" of
vectors.  This graphics device gives the user interactive control over
how this world is viewed.  This frees up the application program to
concentrate on the job of creating and managing this "world", rather
than on how it is displayed.

LGD is simple in that it only line segments and points in space (no
shaded surfaces, hidden-line removal, etc), and does not support a
sophisticated hierarchy of data objects (segments cannot be nested).
Because of its simplicity, however, LGD does not require the large
amount of overhead used by many 3D graphics packages.  Thus for
applications which only need to draw reasonably simple line or point
drawings in 3-space, LGD provides a fast-running, easy to use graphics
environment.

Although one of the main principles of LGD is its independence from
specific graphics devices, I am currently distributing it with only
the "device driver" for the SunView window system for Sun
workstations.  I have also written a device driver for the 3000 series
Silicon Graphics workstations, but it is not yet polished enough for
general distribution.  If you are interested in obtaining it, email me
and I will send it.

If you are interested in writing other device drivers, I will gladly
send you information about how to do so.  I am especially interested
in having an implementation for X windows, so if you know X and are
interested, please let me know!

		     COMPILATION AND INSTALLATION

To install the SunView version of LGD, you must first install GR,
which is the 2D SunView graphics library that LGD uses.  You should
have obtained GR from the same place that you got LGD.  Note: LGD only
requires the 3D version of GR (libgr3d.a); if you do not plan to use
GR separately from LGD, you can delete the 2D GR library file
(libgr.a).

Once you have installed GR, make the changes indicated at the top of
the LGD Makefile, and type 'make' to compile, or 'make install' to
install (and compile).

Note that LGD actually has two Makefiles; the main one, in this
directory, and the device driver one, in the 'sunview' subdirectory.
You should not have to make any changes to the device driver Makefile,
and you should not try to run it separately from the main Makefile.
The main Makefile calls the device driver one automatically.

				FILES

	README:		this file
	Makefile:	the makefile
	lgd.c:		\
	lgd.h:		|  source code files
	internal.h:	|  
	mf.c:		|  (lgd.h is also needed by
	mf.h:		|  application programs)
	vector.c:	|
	vector.h:	/

	lgdintro.tpl:	template for introductory manual page
	lgd.tpl:	template for detailed manual page
	lgddemo.tpl:	template for example application program

	sunview/:	SunView device driver subdirectory


					Mark B. Phillips
					Department of Mathematics
					University of Maryland
					College Park, Maryland 20742
					mbp@lakisis.umd.edu
