I think that it should also be mentioned that Allegro is essentially public domain while SDL is LGPL. I've also considered many times using SDL, simply because I prefer using OpenGL, anyway, and don't need the vast majority of Allegro's functions... I just haven't managed to take that step yet.

[EDIT] Besides, Allegro has the Speedhack... that alone should be worth it, right?

No licence means its 100% proprietary, and no one is technically aloud to use, or distribute it.

A licence is just an "easy" way of giving broad permission to "people" to use and/or distribute your work.

I'm about to run for a train, so no time to post at length. Apologies for that, keep in mind that I'm not being deliberately short.

Oh, I didn't mean the example specifically. It's clearly meant to be a stress test, so 100% CPU is appropriate.

No it doesn't. It can load the LibJPEG (or whatever its called) DLL at runtime, and simply not load JPEGs if the DLL isn't present.

Implementations vary, but the basic idea is that you either (a) use a vsync that sleeps properly (Allegro's may work, it's written in such a way that it may also silently fail); or (b) apply some simple timing logic.

You know how many FPS your game is supposed to work at. So you can work out how long each frame should take. You can also use timing to work out how long each frame has taken. And you can use rest to sleep for the number of milliseconds you specify. So you don't need to use 100% CPU.

We discussed this quite loudly recently, and opinions clearly vary, but for 'pure Allegro' (i.e. no extra libraries), I like this:

Apologies, the above is just typed from the top of my mind, it isn't thoroughly checked.

I don't think so — "SDL_CreateRGBSurface(SDL_SWSURFACE...)" means create a surface for the fastest possible software blitting, which on a PC means the same as creating a memory bitmap in Allegro. The DisplayFormat thing just makes sure that all the bytes/depths/etc are the same as the display buffer. So it creates a new surface, does a colour conversion blit to it from your original, and returns it.

EDIT: I spotted a logical error in the not-100% CPU code I posted above. You should probably change this bit:

      else
      {
         we're too slow, just jump up to date
         skip next frame;
         framestart = my_timer_var;
      }

To something like:

      else
      {
         we're too slow, just jump up to date
         skipped_count++;
         if(skipped_count&7) skip next frame;
         framestart = my_timer_var;
      }

So that if the computer in question just is too slow to play your game, you still display something, allowing the user to realise what is going on. In this case you'll display every 8th frame, still going too slowly.

Oh no! EVERYBODY'S LEAVING! COME BACK! COME BACK TO UNCLE ALLEGRO!

If you like SDL, you should try programming in HTML.

In that case, he should use create_system_bitmap

Is this why www.sdl.cc redirects to allegro.cc, is there something you haven't told us Matthew

There is no such thing as an SDL community. There is only a mailing list for technical problems related to SDL.

productive