For now, OpenGL and Vulkan renderers are broken as I focused on getting
the software renderer working (which was quite tricky to get right).
This fixes a couple of issues: the segfault when warping the screen (due
to the scene rendering move invalidating the warp buffer), and warp
always having 320x200 resolution. There's still the problem of the
effect being too subtle at high resolution, but that's just a matter of
updating the tables and tweaking the code in D_WarpScreen.
Another issue is the Draw functions should probably write directly to
the main frame buffer or even one passed in as a parameter. This would
remove the need for binding the main buffer at the beginning and end of
the frame.
I'm not sure that the mismatch between refdef_t and the assembly defines
was a problem (many fields unused), but the main problem was due to
execute permission on the pages: one chunk of asm was in the data
section, and the patched code was not marked as being executable (due to
such a thing not existing when quake was written).
The attached patch (against quakeforge git) changes the [con]width,
[con]height, and most importantly the rowbytes members of viddef_t
from unsigned to signed int, like in q2. This allows for a properly
negative vid.rowbytes which may be needed in, e.g. a DIB sections
windows driver if needed. Along with it, I changed a few places
where unsigned int is used along with comparisons against the relevant
vid.* members.
One thing I am not 100% sure is the signedness requirements of
d_zrowbytes and d_zwidth: q2 has them as unsigned but I am not sure
whether that is because they are needed as unsigned or it was just an
oversight of the id developers. They do look like they should be OK
as signed int to me, though: comments?
==
Note from Bill Currie: I had to do some extra changes as many
signed/unsigned comparisons were somehow missed.
