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Wednesday, May 20, 2009

Chrome Experiments, Flash-killer, Monster Evolution

These days I am juggling balls. Beside fixing QtWebKit-related bugs, writing more examples on using QtWebKit, I am helping the Kinetic guys with Graphics View optimizations, and working on new Graphics View feature I still can't elaborate (sorry for the teaser :-). On top of that, I already started to work on Qt Script, learning the intricacies of JavaScript along the way, stress-testing Kent's Qt Script binding generators, and surely also playing around with the brand-new Qt Script debugger in Qt 4.5. For the latter, even if you are not really into Qt Script, I highly recommend giving it a try, at least watch the screencast from Kent for a start.

Unless you stayed under the rock for the last few weeks, you already heard about Chrome Experiments. These are some extremely cool demos designed to run in a web browser. Of course, there are already tons of demos out there. Chrome Experiments are however different. It relies on a high-performance browser. The reason: the demo is JavaScript intensive and thus a blazing-fast JavaScript engine will make a different. Coupled with the use of HTML 5 Canvas, some of demos simply show many things which are not possible before. Flash will be still here to stay (due to its authoring tools, advanced features, libraries collections, and so on). But I won't be too surprised if this is going to be a Flash-killer technology. There is O3D but I reckon it tackles a different market segment.

My favorite Chrome Experiment is Monster Evolution, an fantastic demo written by Dean McNamee. Try to launch it in your browser (warning: extremely slow if you don't use state-of-the-art browser). Or just watch the YouTube video. Impressive, isn't it?

When I saw Monster demo for the time, I thought it would be cool to be able to run it as a Qt application. Porting the demo from JavaScript to C++/Qt is one way to do it, but to make the challenge even more painful, I decided to run the monster.js code directly (warning: it's minified, better check Dean's open-source 3-D engine behind the demo). There are tons of ways to do, I almost tried every possible permutations. In the end, I managed to run Monster Evolution smoothly, at more than 25 fps on a fairly modern machine. What was to be just a quick hack turned into a struggling but delirious adventure, resulting in a three-installment series.

For the YouTube generation, here is the time-lapsed screencast (if you prefer, grab the 3 MB AVI).

In the first part, The QtScript Menace, I used Qt's built-in ECMAScript interpreter to run the demo. The performance was not my main concern (though it gave me the chance of using our work-in-progress Qt Script version that uses JavaScriptCore as the back-end), rather the trick on how to run it with as little code as possible. I ended up with a hackish pure JavaScript implementation of the canvas object, along with few lines of glue code, using Qt Script's feature of making a QObject instance available to the script engine. Surprisingly, it works pretty well. It downloads the JavaScript code from the Internet, setups some stuff and then runs it. For a program comprises 240 lines of C++ and 140 line of JavaScript, I am pretty happy.

For the second attempt, Attack of the SquirrelFish, JavaScriptCore was chosen as the engine that powers the demo, used via QtWebKit. Again the same trick was employed, with the glue code now relies on QWebFrame's addToJavaScriptWindowObject and evaluateJavaScript. This requires only minimal changes, with an improved performance as the result (significant and noticeable), especially when JIT is available.

The saga was closed with the third episode, Revenge of the Cylinders. This time the victim was V8, the JavaScript engine which powers Google Chrome. Again, the code change was minimal, consider that V8 glue code to this little Qt application needs to be written manually. Of course this requires you to build V8, I have included the instructions (works on Linux, Mac, Windows) in the accompanying README on how to do that.

Feel free to try all three methods and let us know the frame-per-second speed-up that you get!

Monday, May 18, 2009

the daylight seems to want you just as much as I want you

Like I wrote before, last week I was in Florence for the third installment of Pycon Italia.

I must admit, it was absolutely a fantastic event, so kudos to the the organizer! Everything went without glitches, the auditorium was spacious, coffee breaks and lunch were without compromise. And thanks to our lovely translators, we have on-the-fly, quasi real-time translations both English-to-Italian and Italian-to-English. I guess this is something any others non-English conferences need to copy, it was definitely awesome to be able to follow few talks presented in Italian. Of course, I need to say that it gives a different feeling (for a Python conference) when some VIPs like Guido von Rossum and Alex Martelli were there.

Both my Advanced Graphics Programming with PyQt and David's PyQt for Desktop and Embedded Devices were well received. Things could still have been better, for example I had this funny voice due to my hay fever (which was fortunately cured faster thanks to the Italian warm weather) and I did not realize that I packed too much stuff in the talks. Still, we are pretty content with the way it went. Before you ask, according to the organizer, some time in the future the slides and the video will be available online.

Needless to say, the conference participants were friendly and very passionate. And it was good to meet Enrico again. I also met Matteo whose Qt examples show up from time to time on Planet Qt. We also finally got to know Giovanni and his colleagues from Develer, which was the main drive behind the conference organization. We met a lot of other fellows as well, including KDE evangelists from Salerno. It is still a shame I forgot almost all of my basic Italian, I need to ensure I must polish it before I go to Pycon Quattro.

Beside the conference, Florence proves to be as good as what people say about it. It is beautiful. Amazingly beautiful. And of course, the most important of it, the food was great, as great as it could be. Being a fan of Italian culinary I did sample few excellent dishes, like Pappa al pomodoro and spaghetti frutti di mare. Having dinner outside, in a narrow passage, with happy children running around you, did indeed give a surrealistic atmosphere.

The obligatory picture of the grandeur facade of the Basilica di Santa Maria del Fiore, the central tourist attraction in Florence, follows:

The Cathedral in Florence

But nothing is more breath-taking than walking next to the river, reaching Ponte Vecchio, enjoying its stunning beauty at night, just on last Saturday when it was exactly full moon!

For more conference-related pictures, check out PyCon Tre Flickr group.

Wednesday, May 06, 2009

PyCon Italia Tre, Firenze

Like I mentioned before, I will spend the next few days in Florence (Italy) for PyCon Italia. I'm preparing my slides and demos, including few things I never posted before (premier show, yay!), for the Advanced Graphics Programming with PyQt talk.

According to our flight schedule, tomorrow afternoon David and I shall be in Florence already; so anyone who want to have a chat, drop me an email (ariya.hidayat AT gmail DOT com).