Hardware: General Architecture | Alignment
and Masking | Rigging lasers | Computer-controlled
lasers
Software: The choice of LithTech
| 2D input ->3D world | Iterations
on interactivity | Implementing a storyline
General Architecture
The
eternal Earth Theater is answered! The correct choice is LithTech! See
why in section The Choice of LithTech.
Given Lithtech as a clear choice we immediately set about getting it to
work on five screens. That done we corrected the camera's rotation on
each screen and added masks to help reduce brightness where two screens
overlap. The new Lithtech was surprisingly different (in a good way) then
the older version, making the use of direct code samples from the past
Lithtech group's codebase not advisable so we simply used their good advice.
A camera is sensing the laser points and sending the information to LithTech.
We also went ahead and rigged some lasers in the Earth Theater. Our final
system looks a little like this:
The laser setup, Coolneon and Extesnible hardware base are discussed in the Rigging Lasers section. PPARTO and LANARTO are explained in the Computer-controlled lasers section.
As wee see in the diagram, each of the five screen projectors is connected to a computer that is a LithTech client. Each of these five computers is equipped with a Pentium XXX processor at YYY Mhz with 256 Mb or RAM and an ATI 7500 AGP video card with 64 Mb of VRAM. They are labeled A, B, C, D and E, going from the far left screen to the far right one. The LithTech server is a sixth computer, called the Renderer in the Earth Theater. It is equipped with a Pentium XXX processor at YYY Mhz with 512 Mb or RAM and an ATI 7500 AGP video card with 64 Mb of VRAM. The LithTech server also receives input from the Laser server, which is ETC's Hotlava computer, a Pentium XXX processor at YYY Mhz withe 512 Mb or RAM and a WWWWWW video card with ZZ Mb of RAM. The Laser server is connected to a camera that looks at the central screen and about a third of screens B and D, with a resolution of 640 by 480 pixels. We also implemented laser sensing code, and then scrapped most of it in favor of Cort Stratton's optimized code.
