Opus dual-lens review of 05970306 + 388457a7 (APPROVE WITH FIXES). Four
items, all landed:
1. FOG (behavioural). Retail's D3D fixed-function fog stage runs AFTER the
texture-stage pipeline, so the detail contribution must be fogged, not
just the base. mesh_modern.frag already fogs the base colour
(applyFog(rgb, vWorldPos)) before mesh_detail's replay draws over it;
mesh_detail.frag previously emitted raw detail.rgb, understating fog by
f*a*(fog-detail). Fix: mesh_detail.vert now outputs vWorldPos (mirroring
mesh_modern.vert); mesh_detail.frag declares the identical SceneLighting
UBO and applyFog function (copied verbatim, same binding/std140/math) and
fogs detail.rgb before emitting it. This collapses algebraically to
retail's fog-after-combine order:
(1-a)*mix(base,fog,f) + a*mix(detail,fog,f) = mix(lerp(base,detail,a),fog,f)
RetailDetailTextureContract gains ExpectedFogged(base,detail,opacity,fog,
fogFactor); RetailDetailTextureContractTests pins the identity across 200
random samples within 1e-6.
2. EnvCellRenderer.Rhi.cs's DrawEnvCell-category comment still said "apply
the 10-50 m positive-view-depth fade" — a stale claim from before VM1
removed the fade. Replaced with the mip-chain attenuation statement that
mesh_detail.vert's header comment already carries.
3. Added the test the VM1 contract required but never had: TerrainAtlas
.TryCreateDetailTexture uploads a full mip chain (MipLevelCount ==
RhiWorldTextureArray.MipLevelsFor(w,h), GenerateMipChain called) and
registers with the repeat/linear world sampler, not single-level or
clamped. Drives the private method directly (reflection) against a
synthetic PFID_A8R8G8B8 RenderSurface through a minimal in-memory
IDatReaderWriter fake, so the lane stays hermetic (no installed DAT).
4. #226 pseudocode note: noted that retail's stage-1 OUTPUT alpha
(MODULATE(TEXTURE, CURRENT), 0x0059c549) — the framebuffer blend weight a
delayed-alpha subset composites with — is not modelled; acdream instead
draws a second pass weighted by detail.a*diffuseAlpha. Identical for
opaque subsets, a bounded difference on translucent building/EnvCell
subsets already covered by the existing AP-34 shared-alpha-queue
divergence row. Also qualified the tmpmaterial.Diffuse.a = 1f (0x0059cb99)
citation to name its exact branch (burnedInStaticLights < 0 &&
*(render_device+0x7e4) == 0); the other branch leaves diffuse FromVertex,
but the opaque->1 / fading->opacity mapping still holds either way.
Nit also folded in: EnvCellRendererTests' new SubmitRhi instance-alpha test
is now a [Theory] over WbRenderPass.Opaque and .Transparent, pinning the
bind-before-first-draw invariant on both passes.
Regenerated mesh_detail's committed SPIR-V and the shader manifest
(tools/compile-shaders.ps1); no other shader pair changed.
Verified: dotnet build AcDream.slnx -c Release (0 warnings, 0 errors);
dotnet test on AcDream.App.Tests (Release, hermetic lanes) green, including
the shader manifest tests explicitly; AcDream.Core.Tests unaffected/green.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
VM2's live cdb read against the PDB-paired retail client (GUID
9e847e2f-777c-4bd9-886c-22256bb87f32) proved
m_caps.bCanDoSinglePassDetailing = 1 and trysinglepass = 1 on real hardware,
so D3DPolyRender::RenderMeshSubset (0x0059ca10) never falls back to the
two-pass framebuffer blend the earlier #226 port reproduced. Every loaded
CGfxObj sets use_built_mesh = 1 (CGfxObj::InitLoad 0x005346b0), so buildings
and EnvCells always take the single-pass texture-stage combine set up in
D3DPolyRender::SetSurface (0x0059c4d0):
result = lerp(base * diffuse, detail.rgb, detail.a * diffuse.a)
RenderMeshSubset lights opaque built-mesh subsets with
tmpmaterial.Diffuse.a = 1, so on the live Dereth category texture
0x06006D58 (mean rgb 0.165, mean alpha 0.132) the combine works out to
~0.868 * base + 0.022 — a mild darkening, the opposite sign of the fallback
DstColor blend's brightening.
Also removes the invented 10 m / 50 m distance fade. Retail's
ACRender::get_alpha_for_z (0x006b6230) is only evaluated in
D3DPolyRender::DrawPolyInternal (0x0059d7c0, the immediate-polygon path)
and only when the static noFadeDetail (0x00820e38, initialised to 1) is 0 —
unreachable for built meshes. Attenuation is the sampler's linear mip chain
converging to the texture mean, not a scripted ramp.
Changes:
- mesh_detail.vert/.frag: drop vDetailFade and its distance term; add
vDetailOpacity mirroring mesh_modern.vert's InstanceAlphaBuf (binding 7)
read, and output detail.rgb with alpha = detail.a * vDetailOpacity under
the corrected pipeline blend.
- VulkanViewportMapping.BlendFactorsOf / GpuEnums.GpuBlendMode.RetailDetail:
SrcAlpha + OneMinusSrcAlpha instead of DstColor + OneMinusSrcAlpha.
- RetailDetailTextureContract: replaced the distance-fade constants and
FramebufferFactor with Expected(base, detail, opacity) and IsNeutral,
matching the lerp; contract tests cover zero-alpha/zero-opacity no-ops,
the measured darkening on the live category texture, and full-alpha
replacement.
- Regenerated mesh_detail's committed SPIR-V and the shader manifest
(tools/compile-shaders.ps1); no other shader pair changed.
- Docs: #226's pseudocode note, the docs/ISSUES.md #226 entry, and the
retired TS-52 divergence-register row corrected from the two-pass
DESTCOLOR description to the single-pass path and the darkening
expectation, each citing the VM2 cdb note.
Verified: dotnet build AcDream.slnx -c Release (0 warnings, 0 errors);
dotnet test on AcDream.App.Tests and AcDream.Core.Tests (Release, hermetic
lanes) both green.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
