Running in 640x480 on a wide screen monitor results in pixels wider than high and it looks rather funny. But it's not funny anymore when you try to come up with a solution for the problem .

so my question is: How would you solve this problem?

One solution would be to do it in widescreen mode, but still blit to the screen as if you were in 4:3, and center it so you get black bars to either side.

blit(buffer, screen, 0, 0, screen->w / 2 - buffer->w / 2, 0, buffer->w, buffer->h);

Completely untested. Might be slow, might have artifacts where the black bars should be.

Oh no, you definitely should.

Edit: This seems to work fine.

Edit2: Changed a line for ease-of-use.

What do you think about: My game depends on the hight (it's a vertical shooter) which is 480, the ideal thing to do would be to only change the width. but as far as i can tell that's not possible. I can't find any good resolution to fit my game in widescreen, large resolution isn't an option as allegro is software rendered. .

"normal"?? and what about triple buffering?

Yes, i've heard about that, but never tried it. what about litting and transparent drawing?, if i lit a sprite from video memory to video memory, won't that require more power than from memory to video?.. or am i totaly lost?

Here's a neat trick. Most widescreen monitors support standard vertical resolutions, so when running full-screen just start with 960x480 or something ridiculous and just keep scaling the first number back until set_gfx_mode() finally succeeds.

For example:

for (z = 960; z >= 640; z--)
  if (!set_gfx_mode(GFX_AUTODETECT_FULLSCREEN,z,480,0,0)) break;

if (screen == NULL) { /* Unable to set any graphics mode */ }

--- Kris Asick (Gemini)
--- http://www.pixelships.com

Kris: That's a horrible idea, and you should be subjected to a public beating for even suggesting it. Have you any idea of what that kind of resolution setting abuse would do to my poor monitor?

The other problem with having a widescreen is that although you can get round it with allegro when you're running a creative program like a graphics editor for example what do you do then ? Making graphics like this doesn't seem an optimal way (having to imagine what they'd look like in different proportions).

Just so you know, if you attempt to set a mode which isn't valid, absolutely nothing happens. No switching, no delays, nothing. If a full-screen mode doesn't exist, there's no way for the monitor to actually switch into anything. The monitor driver knows what's valid and what isn't. So short of checking the list Allegro stores internally, that's the simplest method to autodetect a widescreen resolution, since an actual switch will not occur until a valid mode combination of X and Y resolution is chosen. It is a very horrible idea if you're running windowed though! ;)

Ok, I tested that code just to see for myself what would happen. Yes, there was flickering for half a minute as the Allegro window appeared and disappeared rapidly, but short of that it worked. So it does work, it's just not practical.

However, using any autodetect method for widescreen by default is bad because many non-widescreen monitors can actually display widescreen resolutions. So it's good to ask a user on first run of a program, or as suggested, to figure out if the desktop res is a wide-screen resolution or not.

--- Kris Asick (Gemini)
--- http://www.pixelships.com

Is there a way to programmatically determine the aspect ratio of the monitor? get_desktop_resolution() relies on the player having set a proper resolution.

Actually I once did the opposite: set an widescreen resolution on a normal monitor.
I have this ancient MIDI sequencing program, which can display more depending on the horizontal pixel resolution. And I wanted the overview for a particular music.
So maybe they're not retarded: people who incorrectly set their resolution
Look at my self Maybe they are