There were three flags, WF_STRAIGHT, WF_THIN_SPREAD and WF_WIDE_SPREAD,
when only one flag, WF_SPREAD suffices. This makes the code simpler and
gets rid of some duplication.
All functions and variables are now defined in graphics.cpp.
Before, the functions would be compiled again and again for every source
file, now it is compiled only once, halving the size of the stripped
starfighter binary.
Most .h files were not used to declare the externally visible variables
and functions of the .cpp files, but only to #include things and declare
things that were needed by that .cpp file itself. This resulted in a lot
of duplication.
Now the .h files only declare what is externally visible from the
corresponding .cpp files. Starfighter.h includes all the other .h files,
and all .cpp files only #include "Starfighter.h". Functions and
variables that were not used outside the .cpp file that contained them
were marked static. Variables defined in .h files were moved to the
appropriate .cpp files.