Erlkönig: Z (ζῷον)

Z, The Z Project: (from greek ζῷον, “zoion” creature pronounced 「ゾイアン」 or “zoh-yawn”). n, A research project intended to invert the relationship between two-dimensional and three-dimensional applications in the current desktop paradigm in human-computer interfaces. The Z paradigm supports the use of legacy two-dimensional applications within a shared three-dimensional spatial environment. Moreover, the Z environment itself is network-sharable, supporting multiple distributed users and discretionary access permissions, providing a common context for both professional collaboration, shared gaming, and private tasks.

Beyond the desktop

The ΖΩΙΟΝ project is my personal research into spatial environments. Currently only some of the experiments are public, since the rest is still undergoing design churn. :-)

Current Status

2004-12-29 C++ N-Tree[trapezoidal] Class

Currently entangled in the process of writing an STL-like NTree class. It's a bit frustrating that although there are reasonable overviews of writing STL extensions, it seems to be nearly impossible to dig up a good canonical example upon which to base a new template. Grrr. Regardless of the trauma factor however, moving the implementation of the Zones' tree structures into a generic class allows the mechanism to be tested in relative isolation, which is clearly worthwhile.

Part of the quirkiness of the implementation I'm working has to do with the search for LISP-like tree instantiation. With some clever use of + and an auxilliary class, one should be able to generate reasonably efficient code for creating trees with code similar to that used for static initializations. In the example below, copies are made of the original nodes by the + and / operators, with this floating copy, once linked together, assigned to the tree.

It doesn't help, of course, that C++ wants all the happy temporaries in such an expression to be constant, dramatically interfering with the whole goal of linking them without generating gobs of sub-copies.

    typedef NtreeNode_t<std::string> N;
    N tree = (N("a1") / (N("b1") / (N("c1") +
                                    N("c2") ) +
                         N("b2") / (N("d1") +
                                    N("d2") )));

I'm still curious about how to close and reopen the X connection for OpenGL use without mysteriously crashing in glXCreateContext. (Feel like debugging? Take a look at the testcode sample , a structure-flattened C++ regression test-in-progress).

Implementation Notes

The program zland2 was implemented in GNU C. Z and zme are being implemented in C++v3 compiler, originally with Mesa 3.2 and a 3dfx Voodoo3 3000 card (and more recently with an NVidia subsytem, despite the slower framerate at 1600x1200, which just isn't worth it on the NVidia. Perhaps the new Matrox will do better?)

Although moving to C++ helps in some ways, I already miss GNU C's local functions (an issue which neither namespaces nor macros really addresses), and there are numerous other grumbles I'll spare you from.

Related Research

Panda3D is a library of subroutines for 3D rendering and game development. The library is C++ with a set of Python bindings. Game development with Panda3D usually consists of writing a Python program that controls the the Panda3D library

MUPPETS has achieved in-situ development, where system code can be written from within the 3D system itself. Development is active and fairly rich, including but not limited to CAVE integration, data visualization (including generation of 3D representative objects on the fly from the system's internal data), inter-disciplinary virtual theatre, and VR movie creation work. Additionally, a social model has been created within RIT for upperclassmen within the project to mentor lowerclassmen, where the system is an essential component of the scholastic progression. This is part of a general objective to provide a feeling of nearly immediate achievement to lowerclassmen, allowing them to create within a 3D environment almost immediately, instead of studying for some time just to achieve the koan of “Hello World”.

Garry's Mod A Half-Life 2 Modification allowing cooperative modification of a shared environment, which just happens to model physics to a reasonable degree.

Croquet A system that appears to deliver pretty much the complete spatial environment package. Sadly, their response to being slashdotted in June of 2003 was to completely hide the project, still the case in February 2004. Some cached screenshots on this site. It is one of the few shared environments that bothers to have any kind of permission system, and appears to have a large number of available tasks already available by virtue of its implementation in Squeak A detailed review from 1999 is available at itwales.com.

VOS. A promising project. From their website:

The Virtual Object System (VOS) is a hierachical distributed object system, a dessert topping, and a floor wax. It is an infrastructure for object-oriented network communication, and building flexible, distributed object networks for a variety of purposes, but mainly multiuser collaborative virtual environments. It also tastes good and will keep your floors shiny.

The VOS idea of objects having context-carrying links to other objects without constraint to the main tree is intriguing (and more open-ended than Z's action-acquisition menu request), as is their codifying of matrix transform data as generic properties where Z instead currently (2003-10) considers such information as special. The VOS approach would simplify the addition of properties, although there might be issues in implementing the Z permission concept under an open property paradigm rather than as an intrinsic part of the Zone code.

Gel, Billed as "An open source initiative for multi-user internet 3-D", its stated objective to bring in a group of interested developers seems in conflict with the surprising, total lack of screenshots. Nonetheless, the theory involved is on the mark, and downloads are available.

Otools, a object-oriented, multidisplay OpenGL system with the following claims:

Multi session/display object-oriented windowing system.
Very good OpenGL support. Object-oriented virtual reality system.
Crossplatform audiosupport, with realtime 3D audio library (DTDSS).
Networking and Multithreading methods supported in OOP.
Works nicely with supported 3D hardware cards in Linux!

Bamboo, enabling dynamically reconfiguration applications, and written to support Kent Watsen's virtual environments.

The National Tele-Immersion Initiative (NTII) with a focus on full telepresence in a shared virtual environment called a telecubicle.

The Virtual Reality Transfer Protocol (VRTP).

The 3dwm window manager. (originally for the Chalmers Medialab 3D CUBE)

The Berlin Consortium

IBM: a spatial, tool-oriented RealSpace, and the striking conceptual failures of RealPhone, RealCD, and Apple's counterproductively similar-minded QuickTime 4.0.

XEROX/PARC: some minor tools experiments in the UI Research Group