Thanks to validation layers showing command buffer debug regions, it was
pretty easy to find the offending buffers. Did need to modify
QFV_PacketCopyBuffer to take a source barrier as well as the destination
barrier, but this is probably for the best.
While every possible subsystem needs an initialization call, all that
does is add the actual initialization task to the render graph system.
This allows the render graph to be fully configurable, initializing only
those subsystems that the graph needs.
Scripted initialization is still separated from startup as render graph
creation needs various resources (eg, attachments) defined before
creating render and compute passes, but all those need to be created
before the subsystems can actually start up.
Some of them were actual leaks, but tracking memory should be a lot
easier now. However, there's a lot of room for optimization of
allocations (eg, recylcling of hierarchies. There is now 1 active
allocation (according to tracy) when nq exits: Qgetline's string buffer
(I think an api change is in order).
Tracy is a frame profiler: https://github.com/wolfpld/tracy
This uses Tracy's C API to instrument the code (already added in several
places). It turns out there is something very weird with the fence
behavior between the staging buffers and render commands as the
inter-frame delay occurs in a very strangle place (in the draw code's
packet acquisition rather than the fence waiter that's there for that
purpose). I suspect some tangled dependencies.
The grid calculations are modified from those of Inigo Quilez
(https://iquilezles.org/articles/filterableprocedurals/), but give very
nice results: when thin enough, the lines fade out nicely instead of
producing crazy moire patterns. Though currently disabled, the default
planes are the xy, yz and zx planes with colored axes.
