Maya Cornell Box (Learning Maya)
A simple Cornell Box I made in Maya ray traced with caustics and atmospheric effects:
HTML5 Audio Synthesizer
I built this synthesizer purely in HTML and JavaScript using the Firefox audio data API. The way it works is an audio source is initialized with a callback which generates wave data. I coded up three oscillators and a volume envelope to give the sound a little more character.
Key up/down events are trapped and drive the audio when a new buffer is requested. The biggest issue I have with this demo is the huge buffering delay. Unfortunately, I couldn’t do much about it because it’s imposed by Firefox, which requires a 500ms delay between writing audio buffers.
To use it, click the link below, wait for the page to load and then press any of the top two rows of keys on your keyboard (Q-P, and a handful of number keys). You can also tweak the parameters while it’s playing, which is a fun way to torture your friends and family : )
Check it out: http://visualcore.com/htmlsynth/
Tagged Tags: audio, firefox, html on April 11, 2011 at 11:47 pm
Flo: a realtime graphics demo
This is kind of old news (from November, 2010), but here is a video of the demo Shalin Shodhan and I created for the Pixar demoparty (which we won : ). The effects are created with particle systems, fluid dynamics, some shader magic, frame buffers and a constraint solver (for the hair). We built it in about two weeks; the original demo was a real-time executable (3mb):
Tagged on April 11, 2011 at 11:30 pm
Compilers Review
While studying for my compilers final, I made a map of the information covered (using kdissert):
Mandelbrot Zoom
I created this last semester for a class on simulations (which also had a heavy emphasis on fractals). A Mandelbrot fractal is generated and then analyzed for the most “interesting” area to zoom in on.
The following animated gif shows the algorithm in action. The left side is the generated Mandelbrot fractal and the right side is a visualization of the activity detection algorithm. The algorithm is choosing how to zoom into the fractal in real-time (when the image was recorded).
I’ve also posted the Matlab code if you are interested in seeing how it works.
reCAPTCHA
Apparently using WordPress makes you a huge target for spam, so unfortunately I’ve had to resort to using a CAPTCHA again.
I’ve tried some alternative non-CAPTCHA filters, but none of them seem very reliable (some very simple tests were giving false positives).
On a (non-false) positive note, since this is my spring break, I’m trying to get some of my recent projects together and post them this week 
PyMW: Summer-y of Code
Today is the “suggested pencils down” date for Summer of Code and I’m very happy to say that my proposal is complete and I feel the summer was a great success!
For those of you who don’t know, PyMW is a Master-Worker computing framework in Python. It wraps several other Master-Worker frameworks such as MPI, Condor, BOINC or even just using multi-core processors, and exposes them as a simple and elegant API.
The way it works is, you create tasks and submit them to a Master and the master uses an interface/wrapper (BOINC, Condor, MPI, etc) to process those tasks. The master distributes the tasks out to compute nodes (or processor cores), called Workers, and the results get sent back to the Master. This allows you to debug using the multi-core interface (a single machine) and then, by changing one switch on the command line, you can run the same code on thousands of machines using BOINC or any other supported interface.
My proposal was to improve BOINC integration with PyMW by 1) eliminating the startup script and the need to compile C code; 2) adding pure-Python support for BOINC Assimilators and Validators; and 3) by adding a new checkpointing mechanism for long running jobs (optional).
I completed (2) very quickly by virtue of some old Python code I found in BOINC, but (1) took a lot of sweat and tears — the existing BOINC interface was functional, but in need of some serious work. It was running under Mac and Linux, however the Windows client was crashing on every task. To get it working under Windows I ended up creating a C++ launcher application to avoid using batch scripts.
In addition to my proposal, I also added a few other tasks. When working with BOINC, the existing interface assumed that Python was already installed and on the system PATH environment variable. This is not a very safe assumption and so I also crated a portable Python interpreter integrated with the BOINC API. PyMW will now install this interpreter as your BOINC application so that clients no longer need to have Python installed to run PyMW-BOINC compute jobs. Along the way I also created a new logo and graphic design for the PyMW web site and setup WordPress, check it out.
Sadly goal (3) was not completed, however, it was originally proposed as an optional part of the project. I actively chose to pursue the BOINC-Python interpreter over (3) because I felt it was more important to the BOINC interface. In the end, checkpointing can always be done manually, but sending the Python interpreter is a considerably harder task.
I am still wrapping up a few odds and ends, but for the most part, I feel very happy with the state of the BOINC interface. If you are looking for a distributed or parallel processing framework for a future project, please consider PyMW.
If you have any questions or comments, I would love to hear them!
Tagged Tags: BOINC, GSoC, Python on August 10, 2009 at 12:45 pm
PyBOINC Work Continues
I am still working on PyBOINC (the embedded Python interpreter with support for BOINC). The actual integration (exposing the BOINC API to Python) was easy, it’s the cross-platform build that’s most difficult.
The problem is that when running an application on BOINC, you have no guarantee of what libraries will be available, so you must either distribute the libraries you need or compile them statically. I chose the later, which also caused lots of issues with the Python standard library. It’s mostly working now, with the exception of the sqlite module.
I moved the repo over to my bit bucket account since Nicolas is busy with other projects. The latest code can be found here.
Tagged Tags: BOINC, GSoC, PyMW, Python on July 31, 2009 at 4:11 pm
Integrating Python & BOINC
I started working on an embedded Python interpreter for BOINC with Nicolás Alvarez. The interpreter will be the main executable for Python based workunits and provides interop with the BOINC client API. It allows, for example, reporting percentage complete per workunit, which isn’t possible currently with PyMW alone.
The project will likely be incorporated into the BOINC trunk, but the current code is available on bitbucket as PyBOINC if you are interested in seeing how it works.
The Python developers made embedding the interpreter incredibly easy from C/C++ and the BOINC API is readily available from C/C++ as well, so there really isn’t much code. However, packaging the Python standard library and compiling it so it runs on multiple platforms are still going to be challenging.
Tagged Tags: BOINC, GSoC, PyMW, Python on July 12, 2009 at 10:29 pm
Pacman Server Running!
I got the Pacman server running today! It’s processing matches in a round-robin style, not the double elimination tournament yet, but it’s running
This has again exposed the BOINC file immutability issue and I can see now that there is no hacking my way around it — I am going to have to change the interface so that all executables and WorkUnits are uniquely named.
Tagged Tags: BOINC, GSoC, Pacman, Python on July 6, 2009 at 10:14 pm
