This replaces *_NewMap with *_NewScene and adds SCR_NewScene to handle
loading a new map (for quake) in the renderer, and will eventually be
how any new scene is loaded.
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.
Viewport and FOV updates are now separate so updating one doesn't cause
recalculations of the other. Also, perspective setup is now done
directly from the tangents of the half angles for fov_x and fov_y making
the renderers independent of fov/aspect mode. I imagine things are a bit
of a mess with view size changes, and especially screen size changes
(not supported yet anyway), and vulkan winds up updating its projection
matrices every frame, but everything that's expected to work does
(vulkan errors out for fisheye or warp due to frame buffer creation not
being supported yet).
I think the widespread use of recalc_refdef (and force_fullscreen) was
the result of a rushed merge of the renderer and video code (I do seem
to remember sprinkling them around). This cleans the two out of the
client code.
Only CaptureBGR is per-renderer as the rest of the screenshot code uses
it to do the actual capture (which is target dependent). Vulkan is
currently broken due to capture being an asynchronous process and the
rest of the code expecting capture to be synchronous (also, bgr vs rgb).
The best thing is all renderers now write the same format (currently
png).
This is actually a better solution to the renderer directly accessing
client code than provided by 7e078c7f9c.
Essentially, V_RenderView should not have been calling R_RenderView, and
CL_UpdateScreen should have been calling V_RenderView directly. The
issue was that the renderers expected the world entity model to be valid
at all times. Now, R_RenderView checks the world entity model's validity
and immediately bails if it is not, and R_ClearState (which is called
whenever the client disconnects and thus no longer has a world to
render) clears the world entity model. Thus R_RenderView can (and is)
now called unconditionally from within the renderer, simplifying
renderer-specific variants.
Still, nothing will work: no plugins are loaded and they're all broken
anyway.
glx, sgl, glslx etc are going away, just the basics will be built: fbdev
(probably go away eventually), sdl, x11 and hopefully someday win. That's
actually the only reason anything links.
The renderer should now be free of any direct access to client code. Even
3d rendering is now done via a function pointer.
The cshift code is done as a 2d screen function.
