Re: [AD] SF.net SVN: alleg:[12124] allegro/branches/4.9

[Elias Pschernig <elias.pschernig@xxxxxxxxxx>]

trentg@xxxxxxxxxx wrote:
> Revision: 12124
>           http://alleg.svn.sourceforge.net/alleg/?rev=12124&view=rev
> Author:   trentg
> Date:     2009-04-25 05:12:57 +0000 (Sat, 25 Apr 2009)
>
> Log Message:
> -----------
> D3D is somewhat of an oddity in that the
> d3d device can be lost at any time and
> thus the contents of textures lost.
> Presently there are display events that
> are fired when a device is lost and again
> when "found". This isn't good enough.
> Reloading all your textures is a pain
> and the common case is that you just want
> them preserved, even if it's a slight
> performance hit. To solve this the
> driver in a5 "backs up" any modified
> textures when the backbuffer is flipped.
> In most cases this works fine because
> drawing to textures isn't that common.
> However, in some cases it would be nice
> to tell the driver to skip backing up
> certain textures (e.g. temporary
> buffers). This revision allows that
> by adding al_d3d_set_preserve_bitmap.
> In extreme cases (like my game) it
> can speed up al_flip_display by as
> much as 30% if you're using a manual
> double buffer.
>
> I'm open to suggestions on how to
> improve this functionality.

Change it to a bitmap flag, which other platforms can simply ignore (it should 
be defined on all paltforms). Introducing a platform-dependent function always 
should be the last resort, and in this case it's not needed.

It would work like this:

al_set_new_bitmap_flags(ALLEGRO_PRESERVE_TEXTURES)

Or if it has to work on created bitmap, could introduce a new function:

al_add_bitmap_flag(bmp, flag)

and then you could do:

al_add_bitmap_flag(bmp, ALLEGRO_PRESERVE_TEXTURES)