The reversed depth buffer is very nice, but it also reversed the OIT
blending. Too much demo watching not enough walking around in the maps
(especially start near the episode 4 gate).
Other than the rather bad shadow acne, this is actually quake itself
working nicely. Still need to get directional lights working for
community maps, and all sorts of other little things (hide view model,
show player, fix brush backfaces, etc).
This takes care of the type punning issue by each pass using the correct
sampler type with the correct view types bound. Also, point light and
spot light shadow maps are now guaranteed to be separated (it was just
luck that they were before) and spot light maps may be significantly
smaller as their cone angle is taken into account. Lighting is quite
borked, but at least the engine is running again.
I guess it's kind of UB, but it's handy for images that will be
conditionally written by the GPU but need to be in shader-read-only for
draw calls and the validation layers can't tell that the layers won't be
used.
This gets everything but the actual shadow map bindings working: the
validation layers don't like my type punning (which may well be the
right thing) and specialization constants don't help (yet, anyway) but I
want to get things into git.
Directional lights don't get correct matrices yet as I need to study the
math involved for cascaded shadow maps (and id maps don't have
directional lights).
Getting spotlights working correctly was insanely frustrating: I just
couldn't get the entities into the view of the spotlight with any
sensible combination of inverses and the z_up matrix. It turned out it
was all due to an incorrect reference vector: it was +Z instead of +X.
It turns out bsp faces are still back-face culled despite the null point
being on the front of every possible plane... or really, because it's on
the front of every possible plane: sometimes the back face is the front
face, and this breaks the face selection code (a separate traversal
function will be needed for non-culling rendering).
Despite that, other than having to deal with different pipelines,
getting the model renderers working went better than expected.
This involved rewriting the descriptor update code too, but that now
feels cleaner.
The matrices are loaded into a storage buffer as it can get quite big at
6 matrices per light (and the current max lights is 768).
The parameter will be passed on to the pipeline tasks in their task
context, allowing for communication between the subsystem calling
QFV_RunRenderPass and the pipeline tasks (for the case of lighting,
passing the current matrix base index).
They're now qfv_* and shared within the vulkan renderer. qfv_z_up cannot
be shared across renderers as they have their own ideas for the world
frame. qfv_box_rotations currently can't be shared across renderers
because if the Y-axis flip and the way it's handled, but sharing should
be achievable by modifying the other renderers to handle the sides
correctly (glsl and gl need to do lookups for the side enums, sw just
needs to be shown which way is up).
Setting the cvar to > 0 causes demo playback to stop (via demo_speed 0)
when the read packet count reaches the specified value. Very useful for
debugging rendering glitches that are easily reproduced in a demo.
Using set iterators can be quite a lot faster for sparse sets due to the
function call overhead in testing each element. Times for ad_tears
dropped from about 1200us to about 670us (hard to say due to there being
only 3 data points and a lot of noise in the time).
If a step has process tasks, any render or compute
pipelines/renderpasses are **not** run automatically: the idea is the
process tasks need to run the relevant pipelines in a custom manner but
needs the objects to be created.
The recent light changes highlighted that the renderer does not own the
efrags (segfault in qwaq when shutting down my test scene). After
digging through the history of efrag clearing, it turns out that the
renderer never owned them, I just didn't understand the concept of
scenes at the time that I moved efrags into the renderer.
This makes a pretty significant difference: 8-25% for demo1, demo2,
demo3 and bigass1. Many thanks to Nick Alger
(https://stackoverflow.com/questions/5122228/box-to-sphere-collision).
It took me a moment to recognize that it's the Minkowski difference (and
maybe GJK?). Of course, I adapted it for simd.
This eliminates the O(N^2) (N = map leaf count) operation of finding
visible lights and will later allow for finer culling of the lights as
they can be tested against the leaf volume (which they currently are
not as this was just getting things going). However, this has severely
hurt ad_tears' performance (I suspect due to the extreme number of
leafs), but the speed seems to be very steady. Hopefully, reconstructing
the vis clusters will help (I imagine it will help in many places, not
just lights).
I guess I wasn't sure how to find all the allocated entities from within
the registry, but it turned out to be trivial. This takes care of leaked
static entities (and, in a later commit, leaked light entities, which is
how I found the problem).
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.
Based on the article
(https://developer.nvidia.com/content/depth-precision-visualized), this
should give nice precision behavior, and removes the need to worry about
large maps getting clipped. If I'm doing my math correctly, despite
being reversed, near precision is still crazy high. And (thanks to the
reversed depth) about a quarter of a unit (for near clip of 4) out at 1M
unit distance.
