VREng (Virtual Reality Engine)
Current Release:
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Summary
VREng (Virtual Reality Engine) is an Interactive and Distributed 3D Application
allowing navigation in Virtual Worlds connected over the Internet
using Multicast Technology and RTP/RTCP protocol.
- You need the X-Window System (X11R6 either X11R5 either Sun openwin).
- Your screen must have a color depth of 8 or 16 or 24.
- Graphic 3D rendering can be assured by either OpenGL library, either
free Mesa library, either free Tiny-GL library from version 1.4.0 and later.
The Tiny-GL library is now distributed separately
under the name TinyGL-0.1.tar.gz (see download below).
- Your machine and your network must support local IP Multicast (IGMP).
- Your site must be connected on the MBone with routing protocols as DVMRP
or PIM.
- Eventually you need the classical MBone tools like VAT, VIC and WB
which are used by VREng as external applications like helpers.
- Eventually you can use other tools as RAT, FreePhone, Wbd, Nt.
- To display contents of Web Object you need a Browser as Netscape or mMosaic.
- To improve performances VREng uses threads library POSIX compatible,
but if your system doesn't support this feature, downloading gif images is
slower through the Web.
- Others tools, like gv/ghostview to visualize PostScripts docoments,
acroread to visualize Adobe pdf documents, a2ps to print documents,
ssh or telnet and xterm to connect to hosts,...
VREng has not been fully ported on other platforms yet, but any
port will be welcome. For the moment VREng compiles on AIX and
Alpha/Osf.
Works to port VREng on Windows95 have begun (2nd quarter 1998)
but this implementation it's not fully completed (and is not recommended!).
Only VREng sources are available, not binaries.
The VREng sources are under GPL (GNU Public Licence) of FSF
(Free Sofware Foundation) and are available at URL
ftp://ftp.enst.fr/pub/mbone/vreng/vreng.tar.gz.
The latest known Release is , eg
ftp://ftp.enst.fr/pub/mbone/vreng/vreng-.tar.gz.
The CHANGES and recent improvements can be read by
clicking here.
Bug Fixes for this release can be obtained by clicking
here.
The Tiny-GL library, under licence of
Patrice Bellard is free and available at URL
ftp://ftp.enst.fr/pub/mbone/vreng/TinyGL-0.1.tar.gz
The binary of the incomplete port on Windows95
vrexe.zip
and its dll
dll_vreng.zip
are available as-is without any guarantees and no work is planed to achieve this
implementation, so we discourage to use it and sources will be not available.
VREng is written in C language.
First, to create all Makefiles and the config.h, just type:
For systems which support OpenGL natively like Solaris2.7 use:
and then
Just type:
If that works, then install.
Two executable files will be installed by default in /usr/local/bin.
The first will be a script-shell named vre which is a wrapper
to launch the real executable. The second is the real executable
which can be either vreng or vreng.tgl
(vreng using TinyGL) or vreng.ogl (vreng using OpenGL).
To do this, type:
or
You need also to copy the sdr_plugins in your ~/.sdr/plugins directory
or in the common /usr/local/etc/sdr/plugins/ directory.
Three sdr_plugins are supplied:
The new media is "dvr" (Distributed Virtual Reality), the protocol is "rtp"
and the format is "vre". The value of the payload type (PT) is 105.
This step is not required to use vreng.
If you are on the MBone, or if you are familar with de Session Directory sdr,
after installing the sdr plugin, you can use sdr to launch vreng
clicking on the media "dvr", either "dis" or "games" for older versions.
VREng will retrieve automatically world files descriptions and textures
by http from URL:
http://www.infres.enst.fr/net/vreng/
To add your own pictural representation, build a Gif file of your face
(eg. using xv or your favorite tool) and put it in the directory
and update your .Xdefaults with something like that:
and make a xrdb -load ~/.Xdefaults
Virtual Worlds are described in a Ascii configuration file with the suffix
.cfg (eg. world.cfg,
tarots.cfg,
mythology.cfg,
dax.cfg,...).
There is 2 types of lines, objects types and objects definition.
- Objects types, like [wall], [web], [gate],... announce
the type of the following objects definitions.
- Objects definitions, one per line, defines for each object
its position in the space (X, Y, Z, a),
its type (box, sphere, torus,...),
its dimension (width, height, depth, radius,...),
eventually its diffused light (diffuse,ambient,specular,shininess),
and its textures (in x and/or y and/or z).
Textures are defined as classical URL to a Gif file on an
HTTP server somewhere in the real World,
(currently http://www.infres.enst.fr/net/vreng/).
Each virtual world is bound to a Multicast group address, one per world.
For the moment these multicast addresses are not dynamically allocated,
because, at this time, we have not found any mechanism (except SAP/SDP)
to allocate these addresses. These addresses are statically defined
in the configuration file in the range reserved for DIS applications
(224.252.0.0/14). We expect some issues from IETF Malloc Group to
assign dynamically multicast addresses.
At the initialization step, VREng downloads a configation file
of the inital World in Unicast mode under reliable TCP from an HTTP server.
Then all textures of this World are retrieved by HTTP
and kept in the memory cache of the VREng application.
So, the first World you encounter is the "Interconnection World" or
"Rendez-vous World" where you can find Gate boxes to go (or teleport :-))
into other worlds.
All other World's configuration files and textures are downloaded
by the same way.
Requests to this server are multi-threaded if your operating system supports
multi-threading POSIX compliant. This pre-loading can take a certain time
over the Internet, but locally inside a site this operation take
1 to 5 seconds according to the network load and the amount of textures.
Use the arrow keys on your keyboard. There are 6 spatial degrees of freedom
for an avatar:
To identify objects, click on the or of the mouse, the name
of the pointed object will appear, maybe with a pushdown menu containing buttons
to activate an action on this object (for example open/close for a door).
Web objects can be displayed in a scene as an exhibition room and
eventually be opened with a local browser to visit related Web pages.
There are different ways to communicate with other participants in a
same world, either by chating text messages in the input/output
text window under the 3D window, either using traditional MBone tools
like vat, rat, fphone for audio, or wb, wbd for shared whiteboard.
In this case you must switch on the corresponding button in the menu bar.
Existing objects and their actions are:
- RTP/RTCP support (version 1.6.0)
- High Level Language (VREL) to describe VR worlds and objects (version 1.7.0)
- Tcl/Tk Graphical Interface (version 1.8.0)
VREng has been initially written by a group of students
who are not very reachable, because they have left our organization since 1998.
-
Initial Authors
-
Contributors
-
Maintainer
The mailing-list <vreng@inf.enst.fr>
has been opened for any discussion
concerning the VReng application and its evolution. To be added on this
mailing-list, send a message to
<vreng-request@inf.enst.fr>.
You can send Bug-reports and comments to the
<vreng@inf.enst.fr> list.
Have fun!
-- Philippe Dax --
Last modified: Oct 13, 1999 --
