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.
While the scheme of using our own allocated did work just fine, fisheye
rendering uses glGenTextures which caused a texture id clash and thus
invalid operations (the cube map texture happened to be the same as the
console background texture). Sure, I could have just "fixed" the fisheye
init code, but this brings gl closer in line with glsl (which makes
extensive use of glGenTextures and glDeleteTextures). This doesn't fix
any texture leaks gl has (plenty, I imagine), but it's a step in the
right direction.
This makes tex_t more generally useable and probably more portable. The
goal was to be able to use tex_t with data that is in a separate chunk
of memory.
This was caused by an out-by one error when setting up the skin: if cmap
was 0 then the gl_skin struct would be taken from index -1 of the array and
thus cause all sorts of grief.
GL sometimes crashes when building skins. This probably isn't the correct
fix (finding the situation where fb->tex can become NULL despite fb being
non-null is), but it does kill the segfault. Luckily, this is git and this
commit can just be reverted when the real fix shows up. :)
In the end, it turns out this is the correct fix for the gl seg on
overkill, because build_skin will correctly use the fully setup player skin
if the glskin doesn't have a texture associated with it.
If the client receives a skin updated message from the server before having
loaded the player model (shouldn't happen, but some servers have very
strange programmers), no skin data is avaible for updating, so just bail
out.
Where possible, symbols have been made static, prefixed with gl_/GL_ or
moved into the code shared by all renderers. This will make doing plugins
easier but done now for link testing.
