This is an extremely extensive patch as it hits every cvar, and every
usage of the cvars. Cvars no longer store the value they control,
instead, they use a cexpr value object to reference the value and
specify the value's type (currently, a null type is used for strings).
Non-string cvars are passed through cexpr, allowing expressions in the
cvars' settings. Also, cvars have returned to an enhanced version of the
original (id quake) registration scheme.
As a minor benefit, relevant code having direct access to the
cvar-controlled variables is probably a slight optimization as it
removed a pointer dereference, and the variables can be located for data
locality.
The static cvar descriptors are made private as an additional safety
layer, though there's nothing stopping external modification via
Cvar_FindVar (which is needed for adding listeners).
While not used yet (partly due to working out the design), cvars can
have a validation function.
Registering a cvar allows a primary listener (and its data) to be
specified: it will always be called first when the cvar is modified. The
combination of proper listeners and direct access to the controlled
variable greatly simplifies the more complex cvar interactions as much
less null checking is required, and there's no need for one cvar's
callback to call another's.
nq-x11 is known to work at least well enough for the demos. More testing
will come.
Still work with gcc, of course, and I still need to fix them properly,
but now they're actually slightly easier to find as they all have vec_t
and FIXME on the same line.
It turns out cam_controls is for pointing the player model in the
direction of movement rather than controlling the camera (I should add
proper camera controls).
They no longer spin like crazy. I don't know how, but I must have broken
something over the years as I'm sure Seth had the code working (and I
seem to remember seeing it working). In the process, clean up a lot of
the angle mess.
It's a lot easier to read (and see the difference between modes 2 and 3)
with all the ifs removed, and the state is properly is chasestate_t now
(though not handled properly on level reset etc).
The more advanced modes are rather broken (continuous spinning), but
they may have been for a while. The bulk of the various changes were due
to renaming viewstate's origin and angles to make their meaning more
explicit.
Handling of view angles is a little hacky at the moment, but this gets
the chase camera code and most of the common input code into one place,
which will make cleaning up the camera code much easier.
