Some projects

• I managed to get GPT-4 pretty close to emulating a 6502 microprocessor one instruction at a time. GPT-4's results matched my reference emulation for all but 2 instructions out of 288. (Source on GitHub)
• I'm working on an SBC to emulate old 8-bit micros and consoles with NTSC output. Essentially I interfaced an ARM microcontroller to an old TV (as many have) but I tried to make sure it is capable of outputting a video signal very close to an Apple ][, Atari 2600, ColecoVision, and Fairchild Channel F. I wrote a long Twitter thread about the board and another long thread about how Apple ]['s output NTSC video and some of the difficulty programming for it.
• Lawrence Kesteloot and I worked on a ShaderToy tablet for a while. We got as far as converting GLSL shaders in SPIR-V to RISC V assembly, and could reliably run single-pass non-textured ShaderToy shaders on multiple RISC-V cores in an FPGA. It turns out making a GPU is really hard if it's not your day job and you don't have 200 staff.
• I wrote an Apple //e emulator to run my family's old Apple ][ disks. The source is on Github. It builds on MacOS and Linux and supports disk emulation, speaker audio, text mode, lo-res graphics ("GR"), hi-res graphics ("HGR"), double hi-res ("DHGR"), gamepads-to-paddle emulation, and VBLANK probing through per-line video mode capturing sufficient to almost run Vince Weaver's Split Screen Demo. All video modes are supported through GL shaders. Disk images can be dragged-and-dropped onto the disk drives!
• I worked on the Alice 4 handheld computer with other members of the Alice Group. This battery-powered device uses a dual-core ARM CPU and an FPGA to run old SGI graphics demos interactively including tilt and touchscreen.
• I worked on the Alice 3 CP/M retrocomputer with other members of the Alice Group. An ARM Cortex M4 serves I/O requests, a Propeller serves VGA, and a Z80 runs CP/M 2.2.
• Calculate Battery State of Charge (mobile friendly)
• Here's the GitHub repo for a simple interactive GLFW sample that draws a polyhedron with trackball manipulation.

• Check out the ray-tracer in a WebGL fragment shader that I wrote based on a ray-tracer I wrote in 1987 in C on an Amiga 500.

• A long time ago, a bunch of friends and I ported BSD UNIX to the Mac II. We called it "MacBSD". Our code formed the basis for the mac68k port of NetBSD.

• In my spare time many years ago (1999?), I built a tristripping API called ACTC, which is being used by Lawrence Livermore in a visualization system and by Digital Anvil in game authoring tools, among other projects. Before that, I wrote a less flexible tristripping API called Meshifier, used by Ubisoft to create models for their game Ultimate Golf; ACTC fixes several problems in Meshifier and provides a better API.

• Lawrence Kesteloot and I worked for many years on a Z80 homebrew computer that we called the Alice II. We created some web pages documenting our adventures.

Some Personal Writing

• My experience transitioning to Boost::shared_ptr (Feb 3rd, 2010)
• Addiction (Feb 6th, 2009)
• Performance and Participation (Apr 7th, 2008)
• Voice-over-IP to Amateur Radio Bridging (Mar 4th, 2008)
• Geodesic Domes (October 1, 2006)
• My pictures from Burning Man 2005 (September, 2005)
• My first Burning Man (see also burningman.com) (September 18th, 2004)
• My experience with Lexapro, a prescription antidepressant. (August 15th, 2004)
• Back of the Envelope Calculation (October 25th, 2000)

Out and About

• At Burning Man 2006 through 2013, I camped with the Karma Chickens.
• I played drums in 2012 for Suicide Poodles, a classic rock cover band.
• In 2005, with my friends and colleagues David Shreiner and Alan Commike, I filed patent 7,460,126, describing a multithreaded, multipipe media player. The implementation was capable of playing a uncompressed "quad HD" movie (3840 by 2160 pixels) directly from a RAID array of fiber channel SCSI disks. (The target was the Sony SXRD 4K digital projector, which had four inputs, one for each quadrant.) It was a pretty large chunk of code using OpenGL, OpenML, pthreads, and C++. I was kind of proud of the code; it was my first large-scale threaded application. It ran under IRIX 6 and the SGI version of Linux that ran on Itanium. It was, however, not user-friendly and required a pair of full-height racks of equipment. If I remember correctly, Sony declined to work with us after we provided a single demonstration of the technology streaming a short film. A few years later, Sony demonstrated the same projector with a "media block" which was essentially a PC streaming JPEG2000 compressed images to the projector.
• Around 1997, I was peripherally involved in patent 6,933,941, describing a scene graph called Cosmo3D. I think I was just basically the last person remaining at SGI who had worked on the thing at the time. Cosmo3D had features from IRIS Performer promoting performance and features from Open Inventor promoting ease-of-use and editing. (Says it was filed in 2001? What was the delay? I had quit SGI by 1999.) Cosmo3D was quite slick but never saw any real adoption by the industry or even promotion by SGI. (Not to be confused with Cosmo Worlds, a VRML viewer.)
• I appeared briefly in the movie "Revolution OS" playing Richard Stallman's "Open Software Song" with "The Gnu Stallmans". Because of that, I have an entry on IMDB, the Internet Movie Database .
• Back in college, my friend Lawrence and I competed with each other to write the shortest program that would ray-trace shaded spheres and provide an ASCII art image of the result. He made a web page describing our competition. The programs are very ugly and illustrate some things you may not know can be done in the C programming language.
• I organized and moderated a panel called "When Will Ray-Tracing Replace Rasterization?" at SIGGRAPH 2002
• I joined Dave Shreiner in courses at SIGGRAPH 2002, 2003, and 2004 on "Performance OpenGL".
• Neal Tringham fixed my old Meshifier triangle stripping code and used it to create an online optimization tool. Models in Ultimate Golf by Ubi Soft were processed with that tool. (I recommend using my ACTC package, mentioned above.)
• I presented part of and wrote part of the course notes for the SIGGRAPH '97, '98, '99, and '00 full day course called Advanced Graphics Programming Techniques with OpenGL, and also the SIGGRAPH '99 Lighting and Shading Techniques for Interactive Applications course.