[SDL] hardware alpha & colorkey support

Stephane Marchesin stephane.marchesin at wanadoo.fr
Sun Jan 23 08:58:11 PST 2005


sapsan wrote:

> There are some really annoying questions(as for game development 
> process):
> 1)" Does current SDL version has hardware alpha blitting(i mean about 
> hardware per pixel alpha support)?"; 

No, because of a bug in SDL.

No backend currently has support for hardware accelerated alpha.
However, there is a fix for the bug and a backend (glSDL) that does hw 
accelerated alpha in this tarball :
http://icps.u-strasbg.fr/~marchesin/sdl/SDL12-experimental.tgz

>
> 2)"What about a modern hardware graphics without support of hardware 
> colorkey?".

It is the responsibility of the backends to emulate colorkey with alpha.
That's what is done in glSDL, and it's not a big deal.

Stephane







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