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perf(vfx): port retail particle visibility degradation

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Resolve DAT-authored particle ranges from the hardware GfxObj, apply retail distance and completed-cell visibility gates, and preserve the exact finite/infinite off-view update semantics. This removes dense-world simulation work without shortening terrain, entity, fog, or streaming distance.

Publish doorway-clipped outdoor cells through a focused frame controller, retain effect cell identity for outdoor statics, reject hidden emitters before particle-slot scans, and offer an explicit opt-in Extended particle range.

Release build succeeds and all 5,857 tests pass with five intentional skips. Retail-conformance, architecture, and adversarial review cycles are clean; connected Aerlinthe visual/performance gate pending.

Co-authored-by: OpenAI Codex <codex@openai.com>
This commit is contained in:
Erik 2026-07-17 15:27:36 +02:00
parent 82789eea88
commit f1ba147ac5
29 changed files with 1810 additions and 125 deletions
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51
docs/research/deepdives/r04-vfx-particles.md
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@ -638,21 +638,38 @@ totals ("Particles Rendered", "Particle Systems").
Retail did not implement a global particle LRU. Instead, each emitter
enforced its `MaxParticles` hard cap and relied on distance-degrade:
`PhysicsObj.ShouldDrawParticles(degradeDistance)` (ACE
`PhysicsObj.cs:1540-1544`):
`CPhysicsObj::ShouldDrawParticles` (`0x0050FE60`):
```csharp
public bool ShouldDrawParticles(float degradeDistance) {
if (!ExaminationObject) return true;
return !(CYpt > degradeDistance || CurCell == null);
}
```text
if ExaminationObject: return true
if CYpt > degradeDistance: return false
if CurCell == null: return false
return CurCell.IsInView()
```
Particles beyond a per-emitter `DegradeDistance` (ACE stubs it to
`float.MaxValue`) get `SetNoDraw(true)` — they keep simulating (so the
server-side script advances) but aren't rendered. Real retail probably
used a per-`GfxObjDegradeInfo` value; for acdream we can set a sensible
default (50 m outdoor, 15 m indoor) and override via a PluginAPI hook.
The matching x87 `test ah,0x41` admits equal, less-than, and unordered
comparisons. Authored negative/NaN/infinite values are preserved; 100 is used
only when the hardware particle GfxObj has no degradation table.
The exact distance is not guessed. `CPhysicsPart::GetMaxDegradeDistance`
(`0x0050D510`) returns 100 world units when the hardware particle GfxObj has
no degradation table. `GfxObjDegradeInfo::get_max_degrade_distance`
(`0x0051E2D0`) selects entry zero for one/two-entry tables and the
second-to-last entry for larger tables. `ParticleEmitter::SetInfo`
(`0x0051CE90`) stores that value from its first hardware particle part.
`ParticleEmitter::UpdateParticles` (`0x0051D180`) does more than hide the
result. While degraded, an infinite emitter performs no normal particle
integration or emission and freezes its live particle ages. A finite emitter
ages/kills existing particles, records at most one due emission without making
it drawable, and calls the conditional `StopEmitter` duration/count test. It
does not stop merely because it is degraded. If that counter-only emission
reaches the stop condition, retail's logical `num_particles` can remain
nonzero without a drawable `PhysicsPart`; the emitter then remains owned until
explicit physics-object teardown. ACE preserves those two update branches but stubs the
distance to `float.MaxValue`; retail's named code and matching x86 are the
oracle. Full pseudocode and the installed-data fixture are in
`docs/research/2026-07-17-retail-particle-visibility-pseudocode.md`.
---
@ -798,11 +815,11 @@ RenderFrame:
7. UI
```
Simulation runs every frame regardless of visibility (matches retail's
`ShouldDrawParticles` behavior: hidden emitters still advance their
script). This costs a bit of CPU but keeps semantics correct — when an
ally buff expires behind a wall, it should still be gone when you see
them again.
Simulation obeys retail's completed-view and authored-distance gate. Visible
emitters run their full update. Degraded infinite emitters freeze in place;
finite effects still age/retire and run their authored duration/count stop
test, so a time-bounded ally buff effect does not become immortal behind a
wall.
### Silk.NET shader sketch