A scouting pass over V4d stopped before writing code and reported three gaps between terrain and the pinned contract. All three verified against source.
The load-bearing one: terrain_modern.vert declares locations 2-5 as uvec4 and TerrainModernRenderer feeds them with glVertexAttribIPointer, but GpuVertexFormat had no integer format and the encoder only issued glVertexAttribPointer. GL leaves an integer shader input undefined if it arrives through the float path, and Vulkan needs the format named as R8G8B8A8_UINT rather than _UNORM, so UByte4Normalized cannot stand in for it. Those packed bytes carry terrain-type, road and split-direction codes that drive every blend decision, so normalising them would have produced garbage rather than an approximation. Adds GpuVertexFormat.UByte4UInt and an integer branch in the encoder.
Also adds a uniform binding for terrain's 36-float per-layer tiling array, which at 144 bytes cannot ride in the 96-byte push-constant block or Vulkan's guaranteed 128-byte ceiling, and has no uniform-array verb to reach it otherwise.
Corrects two V4d plan rows: TerrainAtlas belongs to V4t with the rest of the texture stack, and terrain has no GPU timer to port since its diagnostics use a CPU stopwatch. The uView/uProjection convergence gets its own pixel-gated sub-commit because it moves a matrix product from per-vertex GPU evaluation to a CPU multiply, and that rounding effect should be attributable on its own.
Files #250: two zero-allocation tests fail about one run in three on an unchanged tree, independent of this campaign. That noise trains everyone to re-run until green, which is how a real regression gets waved through.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
A scouting pass over V4c stopped before writing code and reported two structural blockers. Both verified against source.
The pinned V0 contract was missing a blend mode. WbDrawDispatcher.ApplyRetailBlend selects three blend functions from each DAT surface's TranslucencyKind, and InvAlpha - OneMinusSrcAlpha over SrcAlpha - had no representation. Blend is baked into the pipeline and is not dynamic, so it could not be handled at the encoder, and folding it onto StraightAlpha would have silently changed how every inverse-alpha surface composites. ParticleRenderer needs it too. The contract grows here, in one reviewed commit, rather than a slice inventing a workaround for it.
Retiring V2's interim handle table turns out to be its own slice. The renderers only intern bindless handles; the raw ulong is produced by the texture caches, baked into ObjectRenderBatch, and carried by GroupKey - the bucketing key V4c is forbidden to change - and by CachedBatch, where it gates cache validity. That is now V4t, with its own pixel gate. Until it lands, the world renderers bind their existing interim tables through the encoder as ordinary storage buffers.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Campaign V migrates the renderer from OpenGL 4.3+extensions to a single
Vulkan 1.3 backend on Windows x64 and Linux x64, then deletes the GL path.
Motivation is compatibility and efficiency, not rescue: mandatory
GL_ARB_bindless_texture is the exact floor that parked Slice L (Mesa
D3D12/llvmpipe lack it) while Vulkan descriptor indexing is core, and
per-frame data can be written straight into mapped memory rather than
copied through BufferSubData.
V0 pins the contract every later slice codes against. Nothing consumes it
yet, so this commit changes no runtime behavior.
The seam is a minimal Vulkan-shaped RHI implemented FIRST on GL. That
ordering is the point: the twelve renderers then port one at a time under a
strict pixel gate on the still-shipping backend, so a divergence is
attributed to one slice instead of surfacing at a big-bang integration.
Duplicating renderers per backend was rejected because WbDrawDispatcher is
4,449 lines holding only ~62 GL call sites — the API surface is small and
the retail-fidelity CPU logic is large, and forking the latter is how subtle
regressions enter.
Contract highlights:
- GpuBindingModel pins set/binding numbers dual-legal for GL and Vulkan
GLSL. Storage bindings 0-8 keep today's shader numbering; UBOs move to
their own set, which resolves the binding=1 collision GL only tolerates
because it keeps SSBO and UBO tables separate.
- GpuRingAllocation is a ref struct replacing every per-frame
BufferSubData; the compiler forbids outliving the owning frame.
- GpuTextureSlot replaces bindless handles. Unassigned is a loud
uint.MaxValue sentinel rather than a silent resolve to slot 0 — the
failure mode behind the magenta 1x1 UI placeholder bug. Renderers
needing a fallback take the device's really-registered default slot.
- Renderers always speak GL winding/viewport conventions; the Vulkan
backend compensates with a negative viewport height in exactly one
mapping function.
Verified while writing the plan: acdream's cameras already build
[0,1]-NDC projections (PortalProjection.cs:12-13), which is Vulkan's
convention. No projection rework is needed and depth precision improves,
at the cost of shifted z-fight patterns — the one pre-approved divergence
class, registered per instance at V7.
Gate: Release build green; App suite 3,785 passed / 3 skipped (3,763
baseline plus 22 new contract tests). Note for later slices, recorded in
the plan: run the suite in Release. LandblockBuildOriginTests'
far-strip test asserts behavior that LandblockStreamer.cs:505 deliberately
turns into a loud Debug.Assert in Debug builds, so a Debug run shows one
pre-existing failure that is not a regression.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
