Minetest Triforce

In case you're not familiar with it, Minetest is basically a free, open-source clone of Minecraft, plus some new stuff like Lua mod support. Anyway, I made a very large Triforce on gameboom's mt1.gameboom.net (port 30000) Minetest server some time ago, and this is the result:

Daytime

Nighttime

Evo 2012 - one hype event!

In case you're not familiar with it, Evo is a international fighting game tournament (though Mario Kart was on the roster one year a few years back) held every year in Las Vegas, Nevada. It attracts thousands (if not tens of thousands) of participants and spectators every year from places like Taiwan, Japan, and South Korea. Indeed, many of the top players come from those countries. The live video stream of the tournament attracted almost a hundred thousand viewers from all over the world at its peak, which is an amazing thing.


I wasn't able to watch the tournament in person, but I was able to watch the livestream for the entirety of the Super Street Fighter IV AE 2012 and Ultimate Marvel vs. Capcom 3 events. There were quite a few exciting matches - for me, here are the highlights of the tournament:

Hopefully, I'll be able to watch Evo in person next year, and possibly compete in the Super Street Fighter IV AE 2012 section if I ever buy the game.

Switching to Blogger

I exported my WordPress blog to Blogger - I think I'm going to enjoy the change. We'll see about that in the coming months, though. :)

Switching blog licenses.

I've given it some thought, and I've made a decision: I'm switching the license for the articles I write on my blog from the CC-BY-NC-SA to CC-BY-SA.  I'm switching for two reasons:

• It lets my articles be re-used/re-posted in far more places I do want it to be used (Wikipedia, other places using the CC-BY-SA, etc...)


• I don't think anyone's going to plagiarize my work anytime soon - besides, at the very least, they have to give me credit (the BY clause).

Besides, I think the more liberal licensing terms make the blog more attractive to FOSS enthusiasts, which is a big plus for me since I need all the publicity I can get. Hopefully I'll see the rewards of switching to the CC-BY-SA license in a year or so. :)

Adventures in optimization

Yesterday was the first day I ever had to seriously optimize some code I had written. The code in question? A point cloud implementation.

When I started work on said implementation, I coded the library in pure Python, and tried it out on a 50,000-point volume. It took 15 seconds just to initialize and move the volume - completely unacceptable. I had a lot of optimization work to do.

The first technique I tried was just a faster algorithm. I switched from using a SQLite database to flat dictionaries, which gave a speed boost of around 2 seconds. Next I tried binding expensive non-local variables to local scope - an extra second or so. Now I was out of ideas (most of the performance-intensive code was just simple for loops) - I decided to re-write the code in Cython.

Simply compiling my library took the performance up to about 7 seconds; adding static typing in strategic spots took the performance even farther - to 2 seconds. A few Cython-specific optimizations further (binding class member variables to local scope, for one), and my library could process a 50,000-point volume in about 0.35 seconds.

Unfortunately, that's still way to slow for my needs - I need 0.1 seconds or less (preferably 0.05 or less) per 50,000 points, so I still have a ways to go. What I'll probably do is re-code some of the library in flat C++, and then access that from Cython. I'll try to keep my blog updated on whether or not I'm successful in this venture. :)

My toy scripts - now available on SourceForge!

I've decided to make good use of SourceForge's per-developer project space - a really nice feature, by the way - and upload all the toy scripts I've made over the years to https://sourceforge.net/u/openblocks/code/. All the scripts are licensed under the 3-clause BSD license, so feel free to give them a look and make your own modifications. :)

Keep in mind that since I use Linux as my main operating system, some of the toys that are shell scripts won't work on Windows, unfortunately.

The hashcash algorithm

Yeah, it has a weird name, but it's one of the most interesting (and effective) anti-spam algorithms out there: Hashcash. How does it defeat spam without the end-user even knowing a spam check is taking place? Read on.

No, this isn't a Bayesian filter-like algorithm; this is something completely different. Hashcash involves inserting a piece of Javascript code into your site's comment form that sends a server-generated key as part of the comment form's data. If the sent key doesn't match the one the server sent as part of the comment form, the comment is marked as spam and not posted. Amazingly simple. And this all happens behind the scenes, without your users even knowing a spam check is going on!

Now, this algorithm works solely on the premise that spambots are incapable of running Javascript, so if spammers come up with a spambot that is capable of running Javascript, Hashcash would be in hot water. But again, no such spambot currently exists, so Hashcash is currently a viable spam-blocking algorithm.

I think Hashcash is such I good idea, I'm going to give it a test run on this site using the WP Hashcash plugin for WordPress. Hopefully I won't have to manually deal with spam for a long time to come. :)