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Documentation Table of Contents

The two tables of demos below list many example Syzygy progams, along with a few important bits of information about each:

1. The type of program, either distributed scene graph or master/slave.
2. The source code location; programs in szg/src/demo are part of the base distribution, whereas those in szgdemo are part of a separate package.
3. A brief description. (3) Whether or not additional data not included in the base distribution is required to run it.

Installing the Optional Data Distribution

Many of the example programs require additonal data files to run (the tables below will help you determine which ones you can run with only the data in the base distribution). Previous versions of Syzygy have included an optional data distribution as a gzip-ed tar file. This file has grown too large to be useful. Instead, the data for the demos is now distributed on the Syzygy DVD, which can be obtained from the Integrated Systems Lab (just follow the links to Syzygy from the lab's main page). To install the data, you will simply copy the 'data' folder from the top level of the DVD to your desired location.

Once the data is installed, set the following parameter in the Syzygy database (discussed below) for each computer that will be accessing the data. Of course, you will point to the actual location of the 'data' directory, instead of '/szg/data'.

   <computer> SZG_DATA path /szg/data

This sets the "path" parameter of the SZG_DATA parameter group on the machine named <computer> to /szg/data. Now, the programs will be able to find their data.

Demo Tables

Master/Slave

An easy way to construct an application that runs synchronizedly across multiple computers. Multiple copies of the application run on the cluster, one per rendering computer. One copy is the master and the others are slaves.

Name	Source Code Location	Description	Data distribution required
atlantis	src/demo/atlantis	A port of the GLUT demo to our system. A school of dolphins, sharks, and whales swims around in a clustered formation.	Base
coaster	src/demo/coaster	A port of the GLUT demo. Ride a roller coaster.	Base
hspace	src/demo/hspace	A visualization of hyperbolic geometry, non-Euclidean three-space tiled with dodecahedra. The projection into Euclidean space is controlled by the joystick (backwards/fowards plus what looks like a rotate).	Base
schprel	src/demo/schprel	A visualization of the warping effects caused by travelling near the speed of light.	Base

Distributed Scene Graph

An arGraphicsServer object runs on a control computer which does no rendering. It distributes geometry data to arGraphicsClient objects running on the rendering computers, which display the graphics. The SZG_RENDER/geometry_IP parameter specifies the IP address of the server. The following demos use this method:

Name	Source Code Location	Description	Data distribution required
cosmos	src/demo/cosmos	Four nested tori spinning about different axes.	Base
parade	src/demo/parade	Icosahedral marching "blobbymen". Reference: Jim Blinn, "Nested Transformations and Blobby Man", IEEE Trans. Graphics Oct. 1987, 59-65.	Base
cubes	src/demo/cubes	300 cubes hang in space. They drift slowly, spin furiously, and change textures. A good stress test for your network.	Base
danceparty	szgdemo/danceparty/src	A stage floating in space hosts five motion-captured dancers who move in short looping motions.	Optional

Running Example Programs

There are two basic ways to interact with the demos: in Cluster Mode using a 6DOF-tracked input device with buttons and joysticks, or in Standalone Mode using the tracking simulator.

cosmos, parade, timetunnel, cubes: Push forward on the joystick to move in the direction pointed to by the sensor attached to the joystick; push back to go backwards. While grabbing the object with button 0, rotate the joystick to rotate the object.

avn: only navigation is implemented, not grabbing.

volume: in addition to navigation, press button 0 to step to the next data volume. Grab the data volume with button 2 to rotate it.

q33: move the joystick sideways to rotate the POV; conventional navigation works as well.

salamiman: Grab the cut plane with button 0 to rotate and translate it. Grab the data volume (and the cut plane, implicitly) with button 1 to rotate and translate it. Button 2 toggles the size of the data volume.

skyfly: Hold the wand away from your head to fly in that direction. Tilt the wand up or down to rise or fall.

szglorenz: See szgdemo/szglorenz/README for an explanation of the controls.

Performance Tuning

Many of the demos, especially the master/slave programs, do not require high performance. However, some of the distributed scene graph demos (e.g. cubes) can move more data on high-end hardware. To get the most performance out of such programs, try the following: In szg/src/barrier/arSyncDataServer.cpp, in the constructor, change the initial value of _sendLimit to 200000 and recompile. This value determines how much information the server will accumulate before sending a frame. It can be increased for better networks.

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