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Showing posts from September, 2009

IDF 2009 Larrabee demo

Intel showed their new Larrabee GPU publicly for the first time at their annual developer conference. They showed Larrabee running a ray tracer that was rendering QuakeWars geometry.

The enthusiast scene (e.g. beyond3d) was not impressed by this demo, because, frankly, it wasn't very impressive at an emotional level. The scene was static, no people in it, just waves and a few very small helicopters. It's strange that they didn't even move the camera, which is something that a ray tracing engine should easily be able to to. The camera angle they chose was effective for showing dynamic reflections, but keeping the camera locked down meant a much less interesting demo.

For the same amount of effort they could have come up with a much more visually and emotionally interesting demo. For example, a cascade of brightly colored chrome balls tumbling down a staircase, which would show off both physics and ray tracing.

That they didn't use this early opportunity to sell Larrabee in…

ICFP 2009 contest final scores

Final scores are out, and my team Blue Iris scored 80 out of 328 in this year's ICFP contest. Not as good as last year, ah well. :-) Next year: More sleep!
And here's a video of the contest results presentation from ICFP.

Brick Break - a Javascript Breakout clone

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This weekend I wrote a Javascript clone of the old Atari "Breakout" game. Thanks to the "Canvas" tag it was very easy to write, but I did run into a few problems:

Javascript math is always floating point, so I had to use the "Math.floor" function to convert the results of a division to an integer. This was in the brick collision detection logic, where I am converting the ball's (x,y) coordinates to the bricks that the ball might be hitting.

I was evaluating document.getElementById too early in the document lifecycle, before the corresponding elements existed. This took me a long time to diagnose -- I ended up just moving the getElementById calls to their run-time use, rather than trying to cache the results.

Jack's Brick Break Breakout clone

ICFP 2009 paper on Haskell in the Real World

Here's a good paper on using Haskell to write a commercial application. The authors are practical commercial programmers who tried Haskell to see if it was a more effective language than Ruby:

Experience Report: Haskell in the “Real World”
Writing a Commercial Application in a Lazy Functional Language


Of special interest is the "Problems and Disadvantages" section. It seems that space leaks which are a continuing source of trouble in the authors' application.

Reading this paper reminds me of Tenerife Skunkworks Haskell vs Erlang Reloaded. In that experiment a developer found that Erlang was much better than Haskell for real-time programming.

Back to gnome

Well, 8 hours using wmii was enough for me. Too many apps didn't quite work right. So I'm back to plain-old-boring-but-familiar Gnome.

Technology Trends I'm Keeping an Eye On

In no particular order, here's what I've been studying lately:Javascript. I've avoided this language over the years because of its low speed and shoddy reputation. But the language implementations seem to be getting faster and the available libraries seem to be getting more interesting. I've just watched all of Doug Crockford's YUI lectures on JavaScript, and I'm thinking about trying to use the language in some toy projects.git gui - this git command, available in recent builds of git, make Git changes pretty easy to author.The Undercover Economist - this is a great book about economic theory. It's pretty easy to read while shaving, or waiting for compiles. Lots of good anecdotes and tools for modeling the behavior of consumers and firms. I took 3 economics classes in college, and they didn't teach me as much practical information as I've learned from reading this book.Hacker News - this link voting site has replaced alterslash and reddit programmi…

Dual XHD7714 Road Trip Report

After a month of using the Dual XHD7714, during which my family and I took a 4000 mile road trip, I have to say it's a pretty nice system. We used it almost exclusively as an MP3 player, rather than an HD Radio or a CD player. I loaded 800 songs from our home music collection onto an 8GB memory stick. It was great introducing my kids to some new music. By the end of the trip their favorite songs were Shock the Monkey and The Magical Mr. Mistoffelees.
Some problems specific to the Dual XHD7714:
Bluetooth issues: Bluetooth headset mode only syncs with one phone at a time. This seems to be a common limitation of low-end bluetooth car stereos, but it's quite frustrating for two-driver families like mine.Bluetooth audio streaming mode doesn't sound very good on this radio. However, I didn't experiment with this very much, so it may have been source-material related.USB MP3 player issues: It takes about 5 seconds per GB to index USB stick music each time it starts up.It only re…