Textured triangles preview (Jared Maddox)

I’ve gotten my textured-triangles software to the point that I’m ready
to actually access pixels in an SDL_Surface. If anyone wants to play
with it, the pixel access code is in SRC_TERM() and TRI_REND().

The files are attached as tar files to these two bugs:
https://bugzilla.libsdl.org/show_bug.cgi?id=2888
https://bugzilla.libsdl.org/show_bug.cgi?id=2894
Note that I haven’t tested this for anything other than compilation
yet. Don’t be surprised if there are bugs.

Also, I’ll only be writing pixel access code for 32-bit pixels for
these. If you want more, then you should be able to make the relevant
modifications once that’s done.

This preview is ready for testing.

I decided that implementing some of the features was nuisance, so I
used the SDL RGBA functions. The preview expects to be built in the
same directory as the SDL headers. Links:
https://bugzilla.libsdl.org/show_bug.cgi?id=2888
https://bugzilla.libsdl.org/show_bug.cgi?id=2894

I’ll worry about writing a test program later.

The software textured-triangle renderer compiles & runs without
problems, but for some reason it produces a purely black output image.
I’d appreciate some eyes other than mine on the code. Links:
https://bugzilla.libsdl.org/show_bug.cgi?id=2888
https://bugzilla.libsdl.org/show_bug.cgi?id=2894
All three tars need to be untared into the same directory. They expect
the SDL headers to be in the same directory. I’ve only tested this
with the -m32 flag for gcc.

In the middle of testing the textured-triangle software renderer. I’m
currently having a problem: my pixel READING code regularly crashes,
and I can’t debug the problem because my version of GDB doesn’t
recognize the Windows 7 signal for a debugger breakpoint (!!!).

I need someone with a working debugger (Windows-based, *nix-based,
whatever) to help me with debugging the SRC_TERM function (I’ve used a
goto to narrow down where the crash happens).

Bugzilla pages:
https://bugzilla.libsdl.org/show_bug.cgi?id=2888
https://bugzilla.libsdl.org/show_bug.cgi?id=2894

All three tars are required, in the same directory, with the SDL
headers in the same directory.