I'd like to be able in my game at some point rotate the screen 90°... Is this possible without having to use rotated fonts/objects so they display correctly rotated???

Thanks!!

instead of drawing directly to the screen when displaying your code, write it to an offscreen bitmap. You can then transfer that to the screen with rotate_sprite() or related function. You'll take a performance hit, but it might not really be noticeable on modern hardware.

Do you mean simplyp drawing your "completely rendered" BITMAP to your screen, flipped 90-degrees? If so, you can probably very simply employ the rotate() function (see forum thread http://www.allegro.cc/forums/thread/323382 for others trying to do something similar...).

Will check the thread, thanks!
What I need to do is have a textprintf() call that would write text rotated 90°... Can I do the printf to a bitmap buffer and then rotate it?

yes

How am I supposed to do it? It doesn't rotate and the bitmap appears one pixel to the left and one down... I know this may be bad code but hey I'm learning

DATAFILE *datafile;
BITMAP *bitmap, *temp;

bitmap = create_bitmap(320,200);
temp = create_bitmap(320,200);
text_mode(-1);
set_color_depth(16);
set_color_conversion(COLORCONV_TOTAL);

datafile = load_datafile("test.dat");
blit(datafile[1].dat, bitmap, 0, 0, 0, 0, 320, 200);
textprintf_centre(bitmap, datafile[0].dat, 160, 165, makecol(255, 0, 0), "Please wait... ");
rect(bitmap, 50, 195, 267, 175, makecol(255, 255, 255));
rect(bitmap, 0, 199, 319, 0, makecol(255, 255, 255));
rotate_sprite(temp, bitmap, 0, 0, 90);
blit(temp, screen, 0, 0, 0, 0, 320, 200);
destroy_bitmap(bitmap);
destroy_bitmap(temp);
unload_datafile(datafile);

A) you have to used 'fix' numbers
B) the angle is really 0-255, not 0-360.

rotate_sprite( temp, bitmap, 0, 0, itofix( 64 ) );

In general to convert 0-360 into 0-255 use this

angle * 256 / 360

Thanks!!! That was the trick!

If you want performance, there's more efficient ways to rotate a bitmap 90 decrees (as it's a special case of rotation). However, you'll need to write your own drawing function for that.

I think roatate_sprite already does multiples of 90 degrees with specialized more efficient code.

Yes it does. At least the C version of the code contains a comment somewhere about the trivial cases (i.e. multiples of 90 degrees).

Does this game use matrices to set screen positions? If so, you could alter a few members of the matrix and it'll get rotated automagically.

Nope, no matrices. Anyway with rotate_sprite it works like a charm

Thanks!!