Support for a 32 bit _hwscreen in the SDL backend
|Reported by:||DrMcCoy||Owned by:||DrMcCoy|
This is a patch to add a 32 bit _hwscreen (if the display can handle this color depth).
My motivation was that some images in Ween: The Prophecy use smooth gradients and the 16 bit surface destroys them (bug #1662625). (My initial plan from 2 days ago was using 24 bit, but then I saw that 32 bit depth is far more easier to integrate into the current code.)
This *shouldn't* break anything (it's optional, the default is still 16 bit and the only changes are in the SDL backend and the scalers; everything works for me at least), but save's save, so I'd like to know beforehand (especially from the porters) whether it is indeed correct, there would be any problems (on other systems using the SDL backend, for example), etc..
Two disadvantages though: It introduces some code-dup (in graphics/scaler/intern.h and graphics/scaler/aspect.cpp) and two more tmpscreens in the SDL backend...
It also still switches back to 16 bit when using the HQ-Scalers (but from what I've seen, the orignal scaler converts the image to 16 bit before scaling, too).
Ticket imported from: #1664514. Ticket imported from: patches/716.