This did involve changing some field names and a little bit of cleanup,
but I've got a better handle on what's going on (I think I was in one of
those coding trances where I quickly forget how things work).
This makes bsp traversal even more re-entrant (needed for shadows).
Everything needed for a "pass" is taken from bsp_pass_t (or indirectly
through bspctx_t (though that too might need some revising)).
The software renderer uses Bresenham's line slice algorithm as presented
by Michael Abrash in his Graphics Programming Black Book Special Edition
with the serial numbers filed off (as such, more just so *I* can read
the code easily), along with the Chen-Sutherland line clipping
algorithm. The other renderers were more or less trivial in comparison.
Surfaces marked with SURF_DRAWALPHA but not SURF_DRAWTURB are put in a
separate queue for the water shader and run with a turb scale of 0.
Also, entities with colormod alpha < 1 are marked to go in the same
queue as SURF_DRAWALPHA surfaces (ie, no SURF_DRAWTURB unless the
model's texture indicated such).
The texture animation data is compacted into a small struct for each
texture, resulting in much less data access when animating the texture.
More importantly, no looping over the list of frames. I plan on
migrating this to at least the other hardware renderers.
I found a test map with no texture data. Even after fixing the bsp
loader, vulkan didn't like it. Now vulkan is happy. The "Missing" text
is full-bright magenta on a dim grey background so it should be visible
in any lighting conditions.
Conflagrant Rodent has a sub-model with 0 faces (double bit error?)
causing simply counting faces to get out of sync with actual model
starts thus breaking *all* brush models that come after it (including
other maps). Thus be a little less lazy in figuring out model start
faces.
The models are broken up into N sub-(sub-)models, one for each texture,
but all faces using the same texture are drawn as an instance, making
for both reduced draw calls and reduced index buffer use (and thus,
hopefully, reduced bandwidth). While texture animations are broken, this
does mark a significant milestone towards implementing shadows as it
should now be possible to use multiple threads (with multiple index and
entid buffers) to render the depth buffers for all the lights.
This allows the use of an entity id to index into the entity data and
fetch the transform and colormod data in the vertex shader, thus making
instanced rendering possible. Non-world brush entities are still not
rendered, but the world entity is using both the entity data buffer and
entid buffer.
Sub-models and instance models need an instance data buffer, but this
gets the basics working (and the proof of concept). Using arrays like
this actually simplified a lot of the code, and will make it easy to get
transparency without turbulence (just another queue).
One more step towards BSP thread-safety. This one brought with it a very
noticeable speed boost (ie, not lost in the noise) thanks to the face
visframes being in tightly packed groups instead of 128 bytes apart,
though the sw render's boost is lost in the noise (but it's very
fill-rate limited).
The main goal was to get visframe out of mnode_t to make it thread-safe
(each thread can have its own visframe array), but moving the plane info
into mnode_t made for better data access patters when traversing the bsp
tree as the plane is right there with the child indices. Nicely, the
size of mnode_t is the same as before (64 bytes due to alignment), with
4 bytes wasted.
Performance-wise, there seems to be very little difference. Maybe
slightly slower.
The unfortunate thing about the change is the plane distance is negated,
possibly leading to some confusion, particularly since the box and
sphere culling functions were affected. However, this is so point-plane
distance calculations can be done with a single 4d dot product.
This was one of the biggest reasons I had trouble understanding the bsp
display list code, but it turns out it was for dealing with GLES's
16-bit limit on vertex indices. Since vulkan uses 32-bit indices,
there's no need for the extra layer of indirection. I'm pretty sure it
was that lack of understanding that prevented me from removing it when I
first converted the glsl bsp code to vulkan (ie, that 16-bit indices
were the only reason for elements_t).
It's hard to tell whether the change makes much difference to
performance, though it seems it might (noisy stats even over 50 timedemo
loops) and the better data localization indicate it should at least be
just as good if not better. However, the reason for the change is
simplifying the data structures so I can make bsp rendering thread-safe
in preparation for rendering shadow maps.
And maybe a nano-optimization. Switching from (~side + 1) to (-side)
seems to give glsl a very tiny speed boost, but certainly doesn't hurt.
Looking at some assembly output for the three cases, the two hacks seem
to generate the same code as each other, but 3 instructions vs 6 for ?:.
While ?: is more generically robust, the hacks are tuned for the
knowledge side is either 0 or 1. The later xor might alter things, but
at least I now know that the hack (either version) is worthwhile.
Some very much needed comments :P Still, nicely, I now have a much
better understanding of how the display lists are created (10 years
is a long time to remember how intricate code works (I do remember
fighting to get it working back then))
Vulkan doesn't appreciate the empty buffers that result from the model
not having any textures or surfaces that can be rendered (rightfully so,
for such a bare-metal api).
I doubt the calls were ever actually made in a normal map due to the
node actually being a node when breaking out of the loop, but when I
experimented with an empty world model (no nodes, one infinite empty
leaf) I found that visit_leaf was getting called twice instead of once.
Since it is updated every frame, it needs to be as fast as possible for
the cpu code. This seems to make a difference of about 10us (~130 ->
~120) when testing in marcher. Not a huge change, but the timing
calculation was wrapped around the entire base world pass, so there was
a fair bit of overhead from bsp traversal etc.
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.
Since it is updated every frame, it needs to be as fast as possible for
the cpu code. This seems to make a difference of about 10us (~130 ->
~120) when testing in marcher. Not a huge change, but the timing
calculation was wrapped around the entire base world pass, so there was
a fair bit of overhead from bsp traversal etc.
This makes much more sense as they are intimately tied to the frame
buffer on which a render pass is working. Now, just the window width
and height are stored in vulkan_ctx_t. As a side benefit,
QFV_CreateSwapchain no long references viddef (now just palette and
conview in vulkan_draw.c to go).
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.
This moves the common camera setup code out of the individual drivers,
and completely removes vup/vright/vpn from the non-software renderers.
This has highlighted the craziness around AngleVectors with it putting
+X forward, -Y right and +Z up. The main issue with this is it requires
a 90 degree pre-rotation about the Z axis to get the camera pointing in
the right direction, and that's for the native sw renderer (vulkan needs
a 90 degree pre-rotation about X, and gl and glsl need to invert an
axis, too), though at least it's just a matrix swizzle and vector
negation. However, it does mean the camera matrices can't be used
directly.
Also rename vpn to vfwd (still abbreviated, but fwd is much clearer in
meaning (to me, at least) than pn (plane normal, I guess, but which
way?)).
While there's currently only the one still, this will allow the entities
to be multiply queued for multi-pass rendering (eg, shadows). As the
avoidance of putting an entity in the same queue more than once relies
on the entity id, all entities now come from the scene (which is stored
in cl_world in the client code for nq and qw), thus the extensive
changes in the clients.
While I doubt the difference is all that significant, this should speed
up entity rendering because it cuts out a lot of branching, and
eliminates scanning the same list multiple times only to not do anything
for large chunks of the list.
Regardless of whether the sky is spinning or not, the matrix needs to be
updated with the current origin in order to get the direction vector
right in the shader. Also, it's in the update that the required x-y
plane rotation gets in so the skies move in the correct direction.
This needed changing Vulkan_CreatePipeline to
Vulkan_CreateGraphicsPipeline for consistency (and parsing the
difference from a plist seemed... not worth thinking about).
This gets the alias pipeline in line with the bsp pipeline, and thus
everything is about as functional as it was before the rework (minus
dealing with large texture sets).
I guess it's not quite bindless as the texture index is a push constant,
but it seems to work well (and I may have fixed some full-bright issues
by accident, though I suspect that's just my imagination, but they do
look good).
This should fix the horrid frame rate dependent behavior of the view
model.
They are also in their own descriptor set so they can be easily shared
between pipelines. This has been verified to work for Draw.
BSP textures are now two-layered with the albedo and emission in the two
layers rather than two separate images. While this does increase memory
usage for the textures themselves (most do not have fullbright pixels),
it cuts down on image and image view handles (and shader resources).
Multiple render passes are needed for supporting shadow mapping, and
this is a huge step towards breaking the Vulkan render free of Quake,
and hopefully will lead the way for breaking the GL renderers free as
well.
