Ok, If I run my game in a windowed mode and I want to display the hardware cursor I can do:

   enable_hardware_cursor();
   show_mouse(screen);

And it appears and works fine.

However, when I want to hide the mouse cursor so I can return to the game I can't seem to get rid of the OS cursor!

I'm currently trying:

   select_mouse_cursor(MOUSE_CURSOR_NONE);
   show_mouse(screen);
   scare_mouse();
   disable_hardware_cursor();

And I'm tried various combinations but the hardware cursor is still there. Does anyone have any idea?

Allegro 4.2.0, Windows XP, using AllegroGL 0.4.0 and OpenLayer 2.0

Thanks!
Rich.

Try:

show_mouse(NULL);

Also, in case you do not want to fall back to the software cursor when no HW cursor is available, it's simpler to use show_os_cursor() instead of enable_hardware_cursor()/show_mouse().

Nope, I already tried show_mouse(NULL). I don't know whether because I am using AllegroGL this is relevant?

Any more ideas?

This is the disable_hardware_cursor section (mouse.c):

However, the enable_hardware_cursor in the windows driver is empty (wmouse.c):

/* mouse_directx_enable_hardware_cursor:
 *  enable the hardware cursor; actually a no-op in Windows, but we need to
 *  put something in the vtable.
 */
static void mouse_directx_enable_hardware_cursor(int mode)
{
   /* Do nothing */
   (void)mode;
}

So it seems only allow_system_cursor = FALSE; is really being changed and this is used in show_mouse():

Ok. Show mouse calls:
gfx_driver->hide_mouse();
But I can't find any entry in wmouse.c for this..?

Yes, yes, now I see how you thought that out

My guess is, the AllegroGL GFX_DRIVER needs the methods show_mouse and hide_mouse filled in. And we also need to find out why the current implementation doesn't work at all with fullscreen mode in Windows - I'm sure I have seen games use the mouse in fullscreen mode, so there should be a way to do it.

Right; that's because Windows doesn't need anything special to enable the hardware cursor (or rather, the hardware cursor in Windows doesn't interfere with get_mouse_mickeys() as it does in X11, where get_mouse_mickeys() causes the hardware cursor to be trapped in the window).

Because Windows cannot display a mouse cursor in a full-screen DirectX application. At least the normal Windows way for setting the mouse cursor doesn't do anything in that case. This is documented, so it probably doesn't count as a bug.
If there is a DirectX way of doing this, I couldn't find it when I looked into this.
EDIT: I checked MSDN, several tutorials and SDL at the time; none of them gave a clue that it could be done.

Hm, I think I remember, I got the mouse cursor displayed in some fullscreen app when I did in fact not even want it. But well, probably makes sense in some way, the HW cursor probably interferes with the full control you get over the GFX card with DX. And maybe it changes in Vista.

No, reread what I said: it doesn't work. I tried the exact same thing when I implemented the hardware cursor for Windows a year (two years?) ago.

You were quick then, since I added my edit almost immediately. I actually thought it was a redundant addition... apparently not though

(Redundant because we of course all do our homework before saying that X cannot do Y, right?)

EDIT: On fullscreen OpenGL, that may very well be a different issue (I have really no idea). My understanding is that Windows cannot display a cursor on a fullscreen DirectX surface.