The openGL gsurf library (ogsf), consisting of approximately 20,000 lines
of C code, contains some 180 public functions and about twice as many
internal functions for run-time data storage, manipulation, querying,
and visualization using OpenGL.
The library handles all drawing and lighting operations, including use of
user-defined clipping planes and drawing various style "fences" on clipping
planes when drawing multiple surfaces, and treats datasets as objects which
can be used for various attributes of the rendering.  It allows data
sharing (e.g., same data for more than one attribute of same or different
surfaces), separate masking for each surface, multiple surfaces, vector sets,
or point sets, and will also allow multiple volumes.  The library provides
all query features such as 3D "point on surface", keyframe animation routines,
and full state saving functionality.  Database-specific routines for
interfacing with the GRASS GISlib are kept isolated for easier library reuse
with other databases.  The gsurf library is not dependent upon any particular
interface library, and has been used successfully with both Motif and Tcl/Tk.
It is used for NVIZ visualization tool.


moved from src.contrib/GMSL/NVIZ2.2/lobes/ogsf/
      to   src/libes/ogsf/

Updated src.contrib/GMSL/NVIZ2.2/Gmakefile for that.
10/1999 Markus Neteler

10/99   - changed gsd_img.c to uncompressed IRIS RGB
2/26/96 - some minor cleanup (mca)
