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Initial check-in based on OpenGL Performer 2.4 tree.
-flynnt

Asdfly is a demo program (a variant of perfly) that demonstrates the
Active Surface Definition library. See the Performer relnotes
describing libpfs for more details.

To run asdfly:

1. install performer_eoe.sw.asddata

    It installs the data and configuration files needed by asdfly. The data
    is installed in /usr/share/Performer/data/asddata.

2. Run an asdfly run_* script to see a demo

    Three run_* scripts are provided to run asdfly on the installed data sets:
	run_simple - uses a simple example data set
	run_multi - gives a more interesting demo
	run_multiclip - gives a full ASD terrain demo complete with clipmapping 

    As asdfly is derived from perfly, you should refer to the perfly man page for
    more information on the command line options and basic user interface.

More details about running asdfly and the contents of these scripts are described below:

o Running asdfly with a config file.

    The asdfly program expects a configuration file argument. Three
    sample configuration files are supplied for you to try. For
    your convenience, these files are also located in the
    /usr/share/Performer/data/asddata directory.


    a) Simple demo data "simple.config"
       To see the simple demo program, run:

	% asdfly simple.config

	Contents of simple.config:
	    0
	    /usr/share/Performer/data/asddata/simple.asd
	    3 

	Note: The value three can be any value between 1 and 5


    b) MultiGen demo data "multi.config"
	    To see the MultiGen demo data (produced by MultiGen's
	    Continuous Adaptive Terrain (CAT) tools), run:

	% asdfly multi.config

	Contents of multi.config:
	    0 
	    /usr/share/Performer/data/asddata/mesh.evt


    c) MultiGen demo data with clipmapping
	    To see the MultiGen demo data (produced by MultiGen's
	    Continuous Adaptive Terrain (CAT) tools) WITH clipmap texture,
	    run:

	% asdfly multiclip.config


	Contents of multiclip.config
	    1
	    /usr/share/Performer/data/asddata/mesh.evt


o The PFASDDATA environment variable:

    The provided sample run_* scripts set PFASDDATA to the normal location
    for the installed data:
	/usr/share/Performer/data/asddata/

    To run asdfly on a different data set you can set this environment variable
    to point to the appropriate location.
    Set the environment variable PFASDDATA to match the directory path to
    the asddata directory. Terminate the pathname with a trailing forward
    slash (/).  This variable is used by the clip texture configuration
    files.

    For example, if Performer is installed in the default location
    /usr/share:
    % setenv PFASDDATA /usr/share/Performer/data/asddata/


    Note: The asddata configuration files are set up so that you don't need to
    set PFASDDATA if you run asdfly in the asddata directory. If you try
    to run in any other directory without PFASDDATA properly set, the
    clip texture config files won't find the data, and "asdfly multiclip.config"
    won't work.

What is in asdfly:

The file "pfuterrain.c" gives two examples to show how
pfTerrain can be used: terrainNode() and terrainMultNode().
terrainNode creates a pfGroup that has APP, CULL callbacks set up.
It evaluates the terrain once per frame, with about half of the work
done in APP callback and the rest of the work done in CULL callback.
Cyclebuffers are used to shift the buffers between processes.
The pfGroup has one pfSwitch node as a child. The value of the switch
node is equal to the index of the current cyclebuffer for the CULL 
process, and the value is set by the CULL callback.
The pfSwitch has several geodes that hold the generated terrain
geosets.
The advantage of this arrangement is short lag and tight culling,
however the frame rate is directly affected by terrain evaluation.

terrainMultNode evaluates the terrain in multiple passes in the APP 
process. In this particular example, terrain is evaluated once
every numpasses(e.g. 4) frames. A pfGroup node is created with the
APP, CULL callbacks. The output geoset is double buffered 
between APP and CULL. 
The advange of this approach is that the frame rate is higher than
the terrainNode, but user needs to adjust the culling polytope
according to the flying speed and frame rate.
In this example, we enlarge the FOV by about 8 degrees and bring
in the near clip plane by 20%.

We adjust several variables in the APP callback:
detail LodRanges, maximum LOD evaluated, and load balance ratio.
They are carried over to APP callback via ViewState variable.
User should plug in his/her own controls.

In general, terrainNode() or terrainMultNode() can be called to
add a node with terrain in a Performer scene graph.
The file terrain.c shows how the terrain is plugged into
the perfly. It also shows how you can create a 2nd channel to
view the terrain.

You are welcome to play with the sliders. Turn on and off
the scribed mode to see the terrain change. 
Notice, when you fly at a low speed, terrain morphing is
not very visible.


Credits and Caveats:

The "mesh.evt" database is provided by MultiGen Inc for the sole
purposes of demonstration and may not be distributed, duplicated, sold
or otherwise used for profit except with the permission of MultiGen
Inc, Suite 500, 550 Winchester Blvd South, San Jose, California 95128
USA

Note that the ".evt" and ".asd" files are in temporary file formats for
demonstration purposes only.  Alternate "official" file formats will be
defined and supported by the software vendors, such as MultiGen, in
their tools for constructing IRIS Performer Active Surface Definition
data.