A mesh-stage program reads its draw parameters from the end of the
pipeline's push block (MeshDrawPushOffsetBytes), so its SPIR-V always
declares the push-constant variable. When its user data do not fit the
push range it has no push data of its own and
RecompileResult::pushConstants is empty, and validation refused the draw
with "invalid push constant interface".
Validation now expects the push block of every mesh-stage program and
still requires it to match the recompiler's metadata for the other
stages. agc_driver_mesh_tests draws the triangle list with a geometry
program given no push range for its own data.
The geometry path's merged ES/GS programs (VGT_SHADER_STAGES_EN.GS_EN)
were compiled as mesh-stage programs whose input metadata was never
filled in, so every such draw failed with "mesh shader translation
configuration is not supported".
Recompiler:
- BuildShaderStageInputInfo takes the draw's MeshConfiguration; the mesh
input helpers (primitive size, step and counts) are implemented.
- The prologue emulates one NGG subgroup per workgroup: s2 GS_TG_INFO,
s3 the merged wave info per wave, the GS vertex offsets (ES thread
index times VGT_ESGS_RING_ITEMSIZE, odd strip triangles swapped), the
primitive id, and the ES vertex and instance ids. An indexed draw's
vertex id is read from the index buffer through a raw V# the driver
puts in hidden user words 4..7.
- s_sendmsg GS_ALLOC_REQ becomes MeshAllocate. The epilogue zeroes the
allocation first, clamps it to the output limits, culls primitives no
thread exported and decodes the 9-bit vertex indices.
- The draw parameters live in the last six push dwords. A BDA fault in
a mesh program no longer stops the invocation (as for other programs
with barriers, the fault is recorded and the read returns zero), so
every invocation reaches the subgroup barriers and the epilogue.
- The cache keys cover the mesh configuration; requests serialize its
new esgsItemSize field (version 4).
Driver:
- DecodeShaderStages reads VGT_ESGS_RING_ITEMSIZE (now in the draw key)
and sizes the subgroup for its ES vertices, GS primitives and outputs.
- Stages compile below the mesh draw parameters, which every mesh draw
pushes; the mesh stage always takes part in the push range.
- The index-buffer V# is set per draw (per record on the CPU-resolved
indirect path); the index-buffer alias check spares read-only
elements.
- The workgroup and LocalSize checks count two guest lanes per
invocation on 32-wide subgroups; mesh draws may carry a first vertex
or instance.
agc_driver_mesh_tests (EXCLUDE_FROM_ALL, needs VK_EXT_mesh_shader)
recompiles a hand-assembled merged ES/GS program in the PS5 compiler's
layout and draws indexed and non-indexed triangle lists in one- and
two-wave subgroups and a triangle strip across odd-starting subgroups,
reading the pixels back. agc_shader_replay prints a request's draw and
mesh configuration.
boykopovar
SamG-Coder
Dean Galvin