Re: [AD] Question about 256 colors modes

[Elias Pschernig <elias@xxxxxxxxxx>]

On Wed, 2005-12-14 at 11:54 -0300, Hugo Daniel Caro wrote:
> Hi everybody,
> 
> I guess this is an old topic, but I would like to know
> why, in 256 colors mode, do you "have" to have the
> "black" (rgb=0,0,0) color at the palette[0] in the
> palette table. Is there any reason where it should be
> there? I remember some very old video cards required
> that...
>
> This makes that, if you have other rgb pattern at
> palette[0] rather than (rgb=0,0,0), masked_blit does
> not do it's work.

That's not true. palette index 0 is the masked color, but you can set it
to any color. The reason it was originally used in Allegro was AFAIK, 0
was faster to skip in the ASM code, and pallete 0 was the border color
on old video cards, so already special cased by the HW.

> I would suggest to add another function, something
> like "set_masked_blit_color" to tell allegro which
> color index is to be considered for transparency...
> (which would allow to use other color than black as
> "transparent").

I agree, also for truecolor bitmaps. We should add this to the design of
the new API.

-- 
Elias Pschernig