Ports retail's ParticleEmitterInfo / Particle::Init / Particle::Update
(0x005170d0..0x0051d400) and PhysicsScript runtime to a C# data-layer
plus a Silk.NET billboard renderer. Sky-PES path is debug-only behind
ACDREAM_ENABLE_SKY_PES because named-retail decomp confirms GameSky
copies SkyObject.pes_id but never reads it (CreateDeletePhysicsObjects
0x005073c0, MakeObject 0x00506ee0, UseTime 0x005075b0).
Post-review fixes folded into this commit:
H1: AttachLocal (is_parent_local=1) follows live parent each frame.
ParticleSystem.UpdateEmitterAnchor + ParticleHookSink.UpdateEntityAnchor
let the owning subsystem refresh AnchorPos every tick — matches
ParticleEmitter::UpdateParticles 0x0051d2d4 which re-reads the live
parent frame when is_parent_local != 0. Drops the renderer-side
cameraOffset hack that only worked when the parent was the camera.
H3: Strip the long stale comment in GfxObjMesh.cs that contradicted the
retail-faithful (1 - translucency) opacity formula. The code was
right; the comment was a leftover from an earlier hypothesis and
would have invited a wrong "fix".
M1: SkyRenderer tracks textures whose wrap mode it set to ClampToEdge
and restores them to Repeat at end-of-pass, so non-sky renderers
that share the GL handle can't silently inherit clamped wrap state.
M2: Post-scene Z-offset (-120m) only fires when the SkyObject is
weather-flagged AND bit 0x08 is clear, matching retail
GameSky::UpdatePosition 0x00506dd0. The old code applied it to
every post-scene object — a no-op today (every Dereth post-scene
entry happens to be weather-flagged) but a future post-scene-only
sun rim would have been pushed below the camera.
M4: ParticleSystem.EmitterDied event lets ParticleHookSink prune dead
handles from the per-entity tracking dictionaries, fixing a slow
leak where naturally-expired emitters' handles stayed in the
ConcurrentBag forever during long sessions.
M5: SkyPesEntityId moves the post-scene flag bit to 0x08000000 so it
can't ever overlap the object-index range. Synthetic IDs stay in
the reserved 0xFxxxxxxx space.
New tests (ParticleSystemTests + ParticleHookSinkTests):
- UpdateEmitterAnchor_AttachLocal_ParticlePositionFollowsLiveAnchor
- UpdateEmitterAnchor_AttachLocalCleared_ParticleFrozenAtSpawnOrigin
- EmitterDied_FiresOncePerHandle_AfterAllParticlesExpire
- Birthrate_PerSec_EmitsOnePerTickWhenIntervalElapsed (retail-faithful
single-emit-per-frame behavior)
- UpdateEntityAnchor_WithAttachLocal_MovesParticleToLiveAnchor
- EmitterDied_PrunesPerEntityHandleTracking
dotnet build green, dotnet test green: 695 / 393 / 243 = 1331 passed
(up from 1325).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The central runtime for every client-visible scripted effect server
triggers via PlayScript (opcode 0xF754) — spell casts, emote
gestures, combat flinches, AND lightning flashes during storms.
Previously acdream parsed PhysicsScript from the dat (via DRW) but
had no runner; the PlayScript stub in ParticleSystem.cs was a
no-op.
Decompile provenance (`docs/research/2026-04-23-physicsscript.md`,
`docs/research/2026-04-23-lightning-real.md`):
FUN_0051bed0 — play_script(scriptId) public API — resolves the
dat id, queues into the owner's ScriptManager list.
FUN_0051be40 — ScriptManager::Start — alloc 16-byte node
{startTime, script*, next}.
FUN_0051bf20 — advance one hook, schedule next fire by next
hook's StartTime.
FUN_0051bfb0 — per-frame tick: while head.NextHookAbsTime ≤
globalClock, fire via vtable dispatch.
Port choices:
- Flat List<ActiveScript> vs retail linked list — iteration is
simpler, N is small.
- Scripts keyed by (scriptId, entityId) — replay replaces instead
of stacking, matches retail's "play_script on the same obj
doesn't double-schedule".
- Anchor world pos cached at Play() time — good enough for
short-lived effects (lightning, spell casts). Callers that
need fresh positions for long emote animations can Play()
again each frame (idempotent).
- Constructor takes Func<uint, PhysicsScript?> resolver so tests
don't need DatCollection; production uses the DatCollection
overload that wraps Get<PhysicsScript> with null-on-fail.
- CallPESHook recurses Play() with Pause baked into the
sub-script's StartTimeAbs. Matches retail semantics where
nested scripts fire on the NEXT tick (list iteration order).
Diag: ACDREAM_DUMP_PLAYSCRIPT=1 logs every Play() and every fire as
[pes] lines. Use this to identify the actual script IDs your ACE
server is sending so we can confirm the lightning pipeline when the
server sends a strike.
Test coverage (9 new tests, all passing):
- unknown script returns false, zero id silent-ignore
- hooks fire in order at their scheduled times
- entityId + anchor pass through to sink
- replay same (scriptId, entityId) replaces, doesn't stack
- different entities run independently
- StopAllForEntity cancels that entity's scripts only
- CallPES nested spawn semantics (fires next tick)
- CallPES with Pause delays correctly
No GameWindow wiring yet — Phase 6b handles the 0xF754 packet
handler and Phase 6c plugs the runner into the frame loop.
Build + 742 tests green.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Erik