The normal encode pass writes batches to a section in build scratch
memory. Those batches contain information about the internal node and
the primitive nodes. The encoder is split to avoid the register
pressure of the compressor and maximize occupancy.
The compressor works in two passes because one pass can not guarantee
that every primitive node (except) has at least two triangles. This
guarantee is used to advertise a smaller acceleration structure size to
the application.
During compression, every invocation processes at most two triangles.
Groups of 8 invocations are used to support the maximum triangle count
of 16 that the hardware supports.
The first step of compression is loading the triangle(s). Shared
vertices are deduplicated early to avoid doing it in the compression
loop. The compression loop tries to add triangles to a list of triangles
until the computed node size needed for storing the triangles reaches
the hardware node size. For this, each invocation first deduplicates
vertices with the triangles that have already been picked. It then
computes the node size of the picked triangles plus the candidate
triangles of the current invocation. The invocation that computed the
smallest size is added to the list.
Because it may not be possible to fit every triangle into the same node,
there can be multiple hardware nodes which are written in parallel for
optimal performance. If there are no nodes with only one triangle, all
nodes are written. If there is, compression of the batch is aborted and
the index of the batch is written to build scratch memory. The second
compression pass will repeat the steps above but only for those aborted
batches. The nodes with only one triangle can and are now merged.
It can not be determined during box node encode which triangles will be
compressed together so the encoder also has to fix up the parent box
node's child infos.
Reviewed-by: Natalie Vock <natalie.vock@gmx.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36965>
Emits two triangles per node whenever possible. The nir code will
revisit the triangle node to handle the second triangle only if both
triangles are interescted by the ray.
Reviewed-by: Natalie Vock <natalie.vock@gmx.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35734>
On Navi33, certain box sorting modes combined with infinity/-infinity in
the child AABBs cause image_bvh64_intersect_ray to return garbage node
pointers.
To avoid this, convert infinity to the maximum representable
floating-point value, which will still intersect with any non-inf ray.
Fixes consistent hangs in DOOM: The Dark Ages.
Cc: mesa-stable
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35254>
This patch changes the update code to launch 8 invocations for every
internal node. The internal nodes update their child leaf nodes using
the geometry index and primitive index stored inside the primitive node.
Processing 8 child nodes in parallel is faster than looping over them.
Moving to one dispatch that updates all nodes in one go lets us get rid
of atomics and will also enable updatable BVHs to use pair compression.
Improves Elden Ring (high settings, max RT settings, 1080p) by around
10%.
Reviewed-by: Natalie Vock <natalie.vock@gmx.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34601>
The advantage of using spec constants is that we do not have to include
multiple spirv binaries for multiple variants of a build stage.
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34594>
This is mostly adapted from radv's BVH building. This defines a common
"IR" for BVH trees, two algorithms for constructing it, and a callback
that the driver implements for encoding. The framework takes care of
parallelizing the different passes, so the driver just has to split the
encoding process into "stages" and implement just one part for each
stage.
The runtime changes are:
Reviewed-by: Sagar Ghuge <sagar.ghuge@intel.com>
Reviewed-by: Konstantin Seurer <konstantin.seurer@gmail.com>
The radv changes are;
Reviewed-by: Friedrich Vock <friedrich.vock@gmx.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31433>
This patch adds a header that is shared between the accel struct build
kernels and the dispatch code.
Signed-off-by: Konstantin Seurer <konstantin.seurer@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18376>
