[SDL] 2D API evolution (SDL 1.3/2.0)

[Sam Lantinga]

> > So, using a single four point 2D transforming blit call on the backend 
> > level does seem like a good idea to me. It's clean, simple, does what 
> > we need, and plugs trivially right into the relevant 3D APIs.

> > Ok... This sounds too easy. What are we missing? ;-)

> Implementation? :)
> Adding a feature to the existing software blitters is a daunting prospect,
> since the complexity increases exponentially.

On an amusing note, I put together a script to generate the blit combinations
needed for 32-bit pixel formats in 1.3, and it generated on the order of 800
blitters, and the resulting object code was as big as the entire rest of the
library combined.

I think I'll need to pare down some functionality and add some multi-purpose
blitters in order to make this reasonable... :)

	-Sam Lantinga, Senior Software Engineer, Blizzard Entertainment