Hi, I've got the following code:

Blitting is very slow...the same code in full screen mode is so fast that I can't see the circle moving, while in windowed mode it moves very slowly.

Does anybody know something about this?

Never acquire video bitmaps if you're doing vram->vram blits. You should only acquire bitmaps if you're going to do non-accelerated operations on them.

Just about the only circumstance in which you should use acquire_screen()is if you're doing a memory->vram dirty rectange system.

EDIT: in other words, drop the acquire()/release() calls.

Even if I drop the acquire/release, the problem remains.

I am not trying to use page flipping, but buffering from vram.

I think maybe the problem is due to pixel conversion...because If I reduce the color depth to 16, then the speed is more than doubled.

Is there a way to get the desktop color depth?

If you put the circlefill itself outside the inner loop, does that give you a significant speed up?

while (!keypressed()) {
        circlefill(page2, x, SCREEN_H / 2, 64, makecol(255, 255, 255));
        acquire_screen();
        for(int j = 0; j < SCREEN_H / 32; ++j) {
            for(int i = 0; i < SCREEN_W / 32; ++i) {
                blit(page2, screen, i * 32, j * 32, i * 32, j * 32, 32, 32);
            }
        }
        release_screen();
        ++x;
    }

You are drawing the circle every frame, and drawing directly to video memory is known to be pretty slow.

If you could just blit the circle (but time the frame rate) you would have a better idea of how slow the blitting is..

If your hardware is accelerating some primitives like GFX_HW_LINE then you might get fast drawing. Otherwise it could be the cause of the slowness.

All I'm saying is it could be worth testing to see if it is this than spending a lot of time on the blitting and gfx mode side.

If they knew about Windows programming and the innerworkings of the DirectX driver... maybe.
Anyway, Allegro should use the native RGB ordering used by the video mode (which is why you load bitmaps aftercalling set_gfx_mode()).