| Re: [AD] alpha blending in new GFX API |
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On Thursday 25 January 2007 3:21 am, Milan Mimica wrote:
> The short question: Will alpha blending will available in color depth
> lower then 32-bit?
>
>
> How I see it in http://allegro.dotsrc.org/future/gfx-api.txt, the
> programmer won't be able to create a RGBA bitmap in 16-bit color depth
> (or any other lower then 32-bit mode). The only assumption I'm making is
> that al_create_display_bitmap() will fail with other then desktop's
> color depths on platforms that not allow changing color depth on the
> fly, like X11.
>
> Bitmaps created with al_create_bitmap() inherit color format from the
> parent. Hence, you can only create video bitmaps with the same color
> format as the display bitmap. You see the problem? No way to create a
> RGBA video bitmap. No way to do hardware accelerated blending in 16-bit
> mode. OpenGL does allow that.
>
> Allegro 4.2.1 + AllegroGL suffers from the same design problem. I was
> looking if I could implement alpha blending in AGL, but couldn't because
> I cannot run my X server in 32-bit color depth.
Interesting, this reminds me, What about a 16bit alpha depth? The DS's main
color depth is 5551 (or 1555, whichever), so things like that _need_ to be
supported.
>
> --
> Milan Mimica
> http://sparklet.sf.net
>
>
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Thomas Fjellstrom
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