I have read up a bit on JS timers and I think I can do slightly better by using requestAnimationFrame mechanism. While this helps with precision, reliability remains low, because of random 200ms lags. I guess it has to be garbage collector running or something like that. I will try to investigate further later.

My current problem is with running audio update thread. Since there is no threading support in JS, there are only two things to do:

1) Run it with the same mechanism I use for timers
2) Provide a function to update audio from game's main code

After work, I'll try them both, I guess, to see which one will lead to less lags in audio output.

Edit: huh. My whole browser seem to lag randomly even when JS is not running. So it's not my code, but rather my system OK then, maybe someone could check out updated timer example? I'm now using more precise mechanism for it, but my computer's lags are throwing it off completely

On my system, the total error and event overhead are always approximately the same number. If I don't do anything but have it running, they are approximately zero, but as soon as I start moving my mouse they both skyrocket and take a long while to get back down.

Append: This is probably due to how firefox handles javascript, but they also both steadily rise while I'm on another tab.

Are you using emscripten_get_now() for timing?

If I'm not mistaken that makes use of Date.now rather than Performance.now.

I tried ex_timer_r, here is the stats text at the top - I don't know what to look for in there.

Firefox 28: {"name":"timer_r.firefox28.png","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/7\/7\/77df60eeb568d77acb7baef65da7c177.png","w":785,"h":109,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/7\/7\/77df60eeb568d77acb7baef65da7c177"}

Chrome 34: {"name":"timer_r.chrome34.png","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/1\/c\/1cb1d053b923050a0af2574f85e9486a.png","w":548,"h":94,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/1\/c\/1cb1d053b923050a0af2574f85e9486a"} (apparently the resolution is lower here)

The lines appear jagged sometimes (bottom one step ahead of top). That may be the monitor (60Hz LCD) syncing in the wrong moment.

By the way, if there is any relevant textual debug information (such as max error), it would be nice to dump it in the text console below, making it easy to copy and paste.

ex_audio_simple seems to correctly play several sounds in parallel when I press "1" a few times.

I just tried it in FF 24.1.0 on Linux and nothing happened. Then I told NoScript to allow the entire page, and besides taking up 200Mb memory, even more nothing happened. OTOH, this FF can't even render the wiki properly.

Amazing work! It works fine here in Firefox 25.0 - only strange thing is that it runs in a tiny square area. Still, works really well, including music and sound. I get close to 60 FPS if there's no water and about 30 FPS if there's a lot of water.

MAN! Yhea! it works pretty well here on Chrome, sound and everything.

As Elias says only on a small rectangle but yhea! Good work!

I had a feeling something was wrong with canvas size, but only now I understood it is square instead of rectangle! Ain't I'm a sharp-eyed little Indian... From a quick look, I can't see why is that (everywhere, width AND height are passed correctly as far as I can see), so I'll have to look further into it. This will be the first priority.

I'll check this out. Haven't noticed this myself, but maybe I just didn't play for any prolonged period of time.

Yeah, man, I'm on roll! (and I have a deadline: this game jam I want to use Allegro in starts the next week)

So the plans for the nearest future:

• Fix keyboard problem

• Find out why canvas is rectangular

• Find out why Fullscreen button does not work (if it should)

• Check out performance problems and possible resources leaks

• Compile Freetype and make TTF addon work

• Compile libjpeg or learn to use native browser's image loaders (maybe a sound loader too)

Yay, Skater example is working!

Chrome 34: ~300 Mb per tab (my Chrome runs a separate process for each). ~60 FPS with a single tab, but 10-30 FPS when I open the game in two tabs simultaneously.

Firefox 28: 100-200 Mb per tab. ~60 FPS in active tab, 0 FPS in other tabs. Occasional stumbles in generally smooth reaction.

What's the name of that game jam, by the way?

Also, do you already have some instructions beyond these to share with people on this path?

I might have quoted a figure for debug build with excessive debug information (line numbers). Just the js file is ~14Mb in that case. Or maybe there is a resource leak... Anyway, Gassa here reports a far more reasonable 300Mb per instance of game. There is a param build process which controls how much memory will be allocated for application. I have set it to 128Mb for Skater (which might be excessive).

GamesJamGAMM (page in Russian). I do not have high hopes for myself in it, because I will not be able to take a break from my day job during the jam, but I thought I still should give it a try, make something small and hopefully interesting.

Instructions alone won't help. I had to write some new code for Allegro and also modify some existing code. After I have ironed out the worst bugs, I hope to submit my work to Allegro developers list and see if it can be integrated as one of "official" platforms for Allegro.

I'm not sure if it really can be a part of main Allegro distribution, because it will not be possible to just take any old Allegro-based game and compile it for web, so it kind of break Allegro's abstraction (unless I can find a way to fix this). Even then, I can distribute my modifications separately, if necessary, for those who want them, in the same way Allegro bindings for other languages are distributed.

In any case, I will make my code available for everyone as soon as I'm not ashamed of it

Edit: I haven't touched the code much in the last two days due to a visit to a dentist and overall laziness, but I fixed two issues: arrow keys no longer scroll browser window when pressed and canvas is now rectangular instead of square.

The first issue is a problematic one. To prevent browser from reacting to its own set of keys/hotkeys, I must filter them out inside KeyDown handler. But which hotkeys should I filter? For example, F5 usually reloads page. I don't want to filter it, because it might be useful for a developer, or confusing to user. On the other hand, what if you REALLY want to use that key in your game, and so need to prevent browser from reacting to it?!

The only way to handle this properly that I can see is to block some browser keys (namely, arrow keys and maybe backspace, which acts as a hotkey for Back button) by default, but add a platform-specific function which will allow user to expand list of filtered keys as needed by his game. Something like al_emscripten_filter_key( int keycode, bool onoff );

The second issue was, actually, a bug in Skater! Code in globals.c (read_global_config)

   window_width = get_config_int(c, "GFX", "window_width", window_height);
   window_height = get_config_int(c, "GFX", "window_height", screen_height);

should instead read

   window_width = get_config_int(c, "GFX", "window_width", window_width);
   window_height = get_config_int(c, "GFX", "window_height", window_height);

Also, I have reduced reserved memory size from 128Mb to 32Mb for this demo. I could find no evidences of memory leaks, so I think we're safe on this from for now.

Skater demo is updated. That's all for tonight.

Can't get the latest skater demo to run in SeaMonkey. May have to do with the fact only OpenGL 2.0 is supported by this laptop.

Really impressed with all you've put together so far. The times they are a changin...

Sound is choppy here (to be expected), but it seems to play pretty good! Nice work Max!

Max, here's the console output when I run it on my laptop :

Edit - you meant the error console. Here :
{"name":"608512","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/5\/2\/52f160d336803dc4dc5a4d6b879f0691.png","w":1280,"h":800,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/5\/2\/52f160d336803dc4dc5a4d6b879f0691"}