Mesh::Refit re-uploaded the entire vertex array every frame on the
in-place UPDATE path (full host write + flush + barrier on the direct
path; full re-stage + copy on the staged path), even when only a handful
of vertices moved.
Add VulkanBuffer::UploadDeviceLocalRange — a dirty-range counterpart to
UploadDeviceLocal that writes/flushes/stages/copies and barriers only the
half-open element range [offset, offset+count) of an already-allocated
device-local buffer. It picks direct-map vs staged-copy from the memory
type the buffer was actually allocated with (not the sub-range size, which
PreferDirectDeviceWrite would mis-route), and the direct path's ranged
flush is rounded to nonCoherentAtomSize and clamped to the allocation size
(mappedSize is now recorded for every buffer, not just mapped ones).
Add a dirty-range Refit overload taking the full vertex/index arrays plus
a (dirtyVertexOffset, dirtyVertexCount) window. The full-span Refit now
delegates to it with the whole array as the window. On the in-place UPDATE
path only the declared window is uploaded — the rest of the device buffer
retains last refit's positions; when an UPDATE isn't possible it falls
back to the full-span rebuild, which is why the full arrays are still
passed. The WebGPU/DOM backend keeps API symmetry: it has no hardware AS,
so it ignores the window and rebuilds the host BVH from the full geometry.
BLASBuildOptions exercises the dirty-range refit on the direct path, the
staged path, and the count-change rebuild fallback, asserting AS-handle /
blasAddr stability and zero Vulkan validation errors.
Resolves#119
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
1f4c77000a