"Interactive Image-Space Techniques for Approximating Caustics"
        Chris Wyman and Scott Davis, The University of Iowa

Running the demo:
-----------------

Unzip the package, goto the "\bin" directiory, run the executable 
"causticDemo.exe"

For help with key commands, "h" displays help text on screen.


Initial state:
--------------

This demo uses a 512 x 512 buffer of photons, either using an eye-space
or light-space photon gather for the final caustic.  The user can toggle
between these modes using either "\" or "|".  Temporal filtering can 
either be turned on or off using the "f" key.

The demo starts with temporal filtering OFF, and begins using the eye-space
photon gather.

The eagle has an index of refraction of 1.35, and begins rotating immediately
upon startup. 


Demo requirements:
------------------

A graphics card and driver able to handle the following extensions:
     GL_ARB_VERTEX_PROGRAM
     GL_ARB_FRAGMENT_PROGRAM
     GL_NV_FRAGMENT_PROGRAM2
     GL_EXT_FRAMEBUFFER_OBJECT
     GL_ARB_DRAW_BUFFERS
     GL_ARB_VERTEX_BUFFER_OBJECT  
     GL_ARB_COLOR_BUFFER_FLOAT    
     GL_ARB_TEXTURE_FLOAT         
     GL_ARB_SHADOW                 
     GL_ARB_DEPTH_TEXTURE         

(Our development machine had an AGP GeForce 6800 with 128 MB memory and
a beta nVidia driver, version 80.40.  The demo *should* work with nVidia's
driver version 77.72 and later.)

Requires the GLUT utility toolkit (DLL included), full package available
from http://www.opengl.org/resources/libraries/glut.html

Requires the GLEW 1.3.2 OpenGL Extension library (DLL included), full package
available from http://glew.sourceforge.net

Requires nVidia's CG library, release 1.4 (DLLs included), full pacakage
available from http://developer.nvidia.com/page/tools.html


Note:
-----

The pixel shaders for the eye & light-space gathers are commented reasonably 
well, but the other included shaders are commented poorly at best, and likely
include commented-out dead code from failed experiments along the way.  
Furthermore, virtually all of the shaders are relatively fragile.


Acknowledgements:
-----------------

Lightprobes from Paul Debevec (http://www.debevec.org/Probes/)