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April 25th, 2008

Old Fogeys

I've become a member of Communauto last week, and combined with getting my bike back, means that I'm at what is going to be my peak mobility for the next little while.

Used Communauto a couple of days later to go to a Quadra hackfest at Rémi's, with slajoie as well. I've had a surge of interest in Quadra, but it is a delicate thing to do: we need to release a new stable version before we can hack on the "next generation" version, and while we're getting very close now, there is definitely a momentum thing that can be lost just too easily. And now the kind of things left are packaging related, which isn't the most exciting (so help us out, dgryski!). We've got interesting ideas for future development, but we can't really do any of this for now, since it would make merging from the stable release very annoying (and it already isn't too wonderful at times)...

Getting my bike back meant going to work on bike, and that is ridiculously quick, on the order of six to seven minutes. That's faster than the metro, by a lot (that's only a bit more than the average waiting time, and I don't have to walk to Lionel-Groulx). In my opinion, that's not even good exercise, I hardly have time to break a sweat even if I go fast, so I might end up taking detours on good days (the Lachine Canal bike path is nearby).

Related to Quadra, I've been looking at SDL (which the next version of Quadra uses instead of its internal platform) and SDL_net. It's funny how game developers are so conservative sometimes! I don't know much about 3D games, but in 2D, people seem to develop more or less like they did on DOS more than 10 years ago, which was very limited back then, due to DOS not having much of a driver model. Because of that, since anything more than page flipping and waiting for the vertical retrace (using polling PIO, of course) is specific to every video chipset. A game wanting to use accelerated blits had to basically have its own internal driver model, and when a card was not supported, either the game would look bad (because it would use a software fallback), or would not work at all. In light of that, most games just assumed a basic VGA card (the "Super" part is made of vendor-specific extensions), using 320x200 in 256 colors (like Doom), or 640x480 in 16 colors (ever used Windows' "safe mode"?), with maybe a few extra extensions that were extremely common and mostly the same.

Then, DirectX appeared and all the fancy accelerations became available to games (window systems like X11 and Windows had their own driver model, but could afford to, being bigger projects than most games, and were pretty much the sole users of the accelerations, so they existed). What happened? Game developers kept going pretty much the same way. Some tests by Rémi back then found that using the video memory to video memory color key accelerated blits (with DirectDraw), getting hundreds of frames per second, where the software equivalent could barely pull thirty frames per second on the same machine. About an order of magnitude faster! You'd think game developers would be all over this, but no, they weren't. They were set in their ways, had their own libraries that did it the crappy way, and didn't bother, overall. The biggest user of 2D color keyed blitting is probably something like the Windows desktop icons.

Then, 3D acceleration appeared, and they just didn't have the choice. The thing is, this hardware still isn't completely pervasive, and especially for the target audience of a game like Quadra, who like nice little games and won't have big nVidia monsters in their machines, so using the 3D hardware for that kind of game would leave them in the dust. Nowadays, DirectDraw has been obsoleted and is now a compatibility wrapper on top of Direct3D, so oddly enough, we're back to 2D games having to avoid the acceleration.

Thankfully, in the meantime, the main CPUs and memory became much faster, so you can do pretty cool stuff all in software, but it's kind of a shame, I see all of this CPU being wasted. Think about it: Quadra pulls in at about 70% CPU usage on my 1.5 GHz laptop, so one could think it would "need" about 1 GHz to run adequately, right? Except it worked at just about full frame rate (its engine is bound at 100 frames per second) on my old 100 MHz 486DX! Something weird happened in between...

Game developers seem to be used to blocking APIs and polling so much, it spills over in SDL_net, which uses its sockets in blocking mode, and where one could easily lock up a server remotely by doing something silly like hooking up a debugger to one of the client and pausing it. Maybe unplugging the Ethernet cable would do it too, for a minute or two, until the connection timed out. How awful...