Contract amendment 1 of three, and V4e's content behind it. Plan section 5.5.16
recorded that both particle pipelines draw with per-instance VERTEX attributes
and that the pinned contract could express instanced DRAWING but not instanced
vertex INPUT: one stride, no divisor, one buffer at VertexInputRate.VERTEX. That
is what stopped V4e. This takes the reviewed option (i) - a second vertex
binding with a per-instance rate.
The amendment. GpuVertexLayout grows a per-binding notion (binding index,
stride, input rate) and GpuVertexAttribute names the binding it is fed from,
defaulting to 0; IGpuPassEncoder.BindVertexBuffer takes a binding index. Every
layout written before this slice keeps its exact meaning through
GpuVertexLayout.Interleaved, which is one vertex-rate binding 0 - and
GpuContractTests asserts that as a requirement rather than trusting it. Both
backends carry the rate natively and at no cost: VK_VERTEX_INPUT_RATE_INSTANCE
on the pipeline, glVertexAttribDivisor recorded once into the pipeline's VAO
where it survives every later attribute rebind.
GpuVertexFormat.UInt1 comes with it, and is necessary to it: particle.vert
declares `layout(location = 6) in uint aTextureIndex` and the amendment's whole
premise is that no shader is edited. Same kind-distinction UByte4UInt was added
for at V4d - GL needs glVertexAttribIPointer, Vulkan needs R32_UINT, and the
float path would reinterpret the value's bits rather than approximate them.
Options (ii) and (iii) were rejected on the record: all ten storage bindings are
spoken for and reusing binding 0 would have the GL particle draw clobber
WbDrawDispatcher's instance array mid-frame (section 5.5.8's hazard in its GL
form); CPU-expanding instances is 5x billboard bandwidth and does not scale to
mesh particles at all.
The arm. ParticleRenderer.Rhi.cs is a SECOND arm per section 5.5.6, not a
replacement - every GL statement in the sibling file is the one it always
issued. Five pipelines replace the imperative glBlendFunc switch (two billboard
blends, three mesh blends) because core Vulkan 1.3 does not make blend dynamic.
The per-flight VAO/VBO pool disappears because every ring allocation inside a
frame is already distinct memory that lives until the frame retires. The
binding-9 table is not bound at all - the device owns the table and the encoder
binds set 2. The pass is BORROWED from IWorldPassScope. Depth tests but does not
write, compare is Less and alpha-to-coverage is off, which is the ambient GL
state particles have always drawn under rather than a choice. Everything above
the submission seam - emitter iteration, retail distance ordering, the
deferred-alpha handoff, billboard axis construction, blend resolution - is the
same CPU code on both arms.
The first Vulkan particle frame threw rather than drew, which is the second
defect of the compiles-clean class this slice found by running:
TextureCache.AcquireParticleTexture is bindless-only, so the standalone particle
texture cache did not exist on a backend without GL. It exists on both arms now.
Everything about it that matters - sharing equivalent surfaces between emitter
owners, the bounded unowned LRU, retirement behind the frame-flight fence - is
already backend-neutral; only how one entry is created and destroyed differs,
which is what IStandaloneBindlessTextureBackend is for. The RHI arm creates the
image through IGpuDevice.CreateTexture with a real sampler and releases the
table slot before the image, which is the GL arm's order and for the same
reason. The composite cache stays GL-only: it serves entity appearance, not
particles.
The durability fix V6k earned. That slice found the sky declaring a 32-byte
stride against a 36-byte AcDream.Core.Terrain.Vertex - the record carries a
TerrainLayer no sky attribute names - and noted that every .Rhi.cs arm restates
a CPU record's footprint from memory while only sky had a test.
RhiVertexLayoutStrideTests is that test for the rest: world mesh, terrain, sky,
retained-UI sprite, debug line, and both particle bindings, each asserted
against the record or the producer's own float count, plus two sweeps over all
seven for attributes that reach past their stride or name an undeclared binding.
Four private layouts became internal to be assertable; nothing else about them
moved.
Gates. Release build green. App tests 4,121/3 skips (4,109 baseline plus three
contract tests and nine layout tests); complete Release suite 9,184/5. Strict GL
offline pixel gate against 08ffe141: 3.20e-05, 18 differing pixels of 563,200,
inside the documented 9-31 band. GL connected -Runs 3: 3/3 RENDERED on the
desktop witness and 3/3 on the client capture. One offline Vulkan run with
VK_LAYER_KHRONOS_validation proven inserted by the loader: zero validation
errors, zero warnings, a captured world frame that still draws terrain,
blending, roads, water, statics, scenery, sky and the complete retained UI.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The rest of V4t. The composite, particle and shared-atlas texture paths now
hand out the device's GpuTextureSlot instead of a raw 64-bit
ARB_bindless_texture handle, and GroupKey, CachedBatch and ObjectRenderBatch
carry that slot. WbDrawDispatcher, EnvCellRenderer and ParticleRenderer retire
their interim GlBindlessHandleTable instances and share the device's one
table, exactly as V4t-1 did for terrain. Nothing about world submission
changes otherwise: these three renderers are still raw GL, still bind binding
9 themselves, and still draw the same geometry in the same order.
**What produces a slot now.** CompositeTextureArrayCache's GL backend interns
each array's handle when it makes it resident and retires the entry when it
makes it non-resident, so the pair is created and destroyed together and the
cache above it never learns a device exists — the fake backend its tests use
mints a stand-in slot. TextureCache.AcquireParticleTexture does the same for
the one-layer particle arrays it owns, including on its rollback path.
ObjectMeshManager registers each shared atlas's wrap/clamp handles at batch
upload; registration is idempotent by handle, so the many batches sharing an
atlas share its entry.
**Slot release is stricter than what it replaces, not looser.** The interim
tables never released anything — the class comment said so — and they grew
without bound. The device's table has a fixed 16,384-slot capacity, so an
unreleased entry is now a leak with an end. Every producer therefore retires
its entry: the composite backend at MakeNonResident, the particle backend at
MakeNonResident, and ObjectMeshManager when a retiring atlas's PHYSICAL
retirement completes — the point at which its handles are already non-resident
and its texture already deleted. That last one needs the handles snapshotted
at eviction, because ManagedGLTextureArray.Dispose zeroes its own copies as
its first act. Teardown deliberately does not release: the device is being torn
down alongside its callers, so there is nothing left to recycle a slot into,
and deferring work through a possibly-disposed retirement queue would turn a
clean shutdown into a throw.
**The default value became load-bearing, and that is the one real hazard here.**
BindlessTextureLocation could say "not resolved" with handle 0, because no
texture has handle 0. A slot index has no spare value — default(GpuTextureSlot)
is real slot 0 — so a positional record would have turned every
budget-rejected or still-uploading composite into a silent read of whichever
texture registered first. That is the magenta-placeholder failure shape one
layer down. The type is now a struct storing the slot one-based, so default IS
Unresolved, with a test pinning both halves: default is unresolved, and a
location naming slot 0 is resolved and distinguishable from it. Elsewhere the
sentinel is already exact — GpuTextureSlot.Unassigned is 0xFFFFFFFF, which is
common.glsl's ACDREAM_TEXTURE_NONE — so the classify path's "no texture yet"
test and the particle billboard's untextured branch are unchanged in meaning.
**GroupKey ordering is preserved because the key never ordered anything.**
Handle→slot is a bijection (the device interns one slot per resident handle),
so the same (entity, batch) pairs bucket together as before. The key reaches
equality, hashing and the scene-digest fingerprints — never a comparator:
opaque and translucent groups sort by cull mode then camera distance, the
delayed-alpha path by viewer distance then submission ordinal, and group
enumeration follows the persistent dictionary's insertion order, which a
changed hash does not disturb. The digests hash the slot index where they
hashed the handle; both sides of the render-shadow comparison compute them the
same way, so the value changing is invisible to it. Read
CompareOpaqueSubmissionOrder, CompareTransparentSubmissionOrder and
AlphaFingerprintComparer before doubting this — sort-order drift is a
pixel-visible regression class this project has hit, and it is why the check
was made before the retype rather than after.
**One visibility change, forced rather than chosen.** BindlessTextureLocation
was public and now holds an internal contract type, so it is internal;
ObjectRenderBatch.TextureSlot is internal on an otherwise public class for the
same reason. Nothing outside this assembly and its InternalsVisibleTo test
assemblies named either.
**SkyRenderer keeps its interim table**, and the report should say why: the
sky's textures are minted by SkyRenderer itself from TextureCache's raw GL
texture names, which this slice does not retype, so it would be the one
consumer registering handles it produced — a different shape from the world
stack. The offline gate also masks the sky band, so the one automated
instrument here cannot see a sky regression. V4f owns that renderer.
**Gates.** GL offline pixel gate vs cb2a70b8, measured twice: 31 and 22
differing pixels of 563,200 (5.50e-05, 3.91e-05). The first is above the
plan's documented 15-23 px band, so a control was measured rather than
assumed: two same-commit captures at this tree differ by 19 px, and — the
decisive number — a capture at V4t-1 and a capture at this commit differ by
9 px, fewer than the same-commit control. Maximum channel delta is 41-52 in
every pair including the controls, i.e. the differing pixels are drawn from
one flickering population, not from moved geometry. tools/run-repeat-connected-gate.ps1
-Runs 3: 3/3 RENDERED on both the desktop witness and the client capture. One
Vulkan composition-host run with VK_LAYER_KHRONOS_validation proven inserted
by the loader: zero errors, zero warnings, converged ownership ledger. App
tests 4,077 / 3 skips and the complete Release suite 9,140 / 5 — both the
4,075 and 9,138 baselines plus the two tests added here.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Erik