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fix(physics): make collision activation starvation-free

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Erik 2026-07-31 18:34:46 +02:00
parent d94145e6b8
commit 6b28ff999c
14 changed files with 4637 additions and 474 deletions
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docs/architecture/acdream-architecture.md
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@ -494,13 +494,47 @@ What exists and is active:
target prefix (including a withdrawn repair marker); target-root statics come
from the authored replacement. Runtime mutation-gates their exact capture,
refreshes each through the host work meter, and builds every cache/graph/
shadow replacement list through one-work-unit seal cursors. The final update-
thread activation performs one mutation-version check and installs the sealed
records without heap allocation before emitting
`CollisionGenerationCommitted`. Cancellation disposes only the named staging
generation and never withdraws the previous active world. Thus readers see
the complete old generation or complete new generation, never a mixed
cell/cache/shadow world.
shadow replacement through one-work-unit seal cursors. Stable per-prefix
owner slots replace the former registry-global mutation gate. One Runtime-
scoped versioned journal coalesces repeated live mutations by owner instead
of copying the owner into every draft on every event. Each draft reconciles
only the latest exact state for owners changed during its lifetime, one owner
per seal step, so unrelated or continuously moving owners cannot restart the
target cursors. Once discovered, a relevant owner receives exact subscribed
updates without restoring global fanout. First entry to or departure from a
target after the global slot cursor has passed is routed through the owner's
changed prefix to that one matching draft. During topology construction a
visited unrelated owner receives only a cheap coalesced dirty notification;
its exact mirror is deferred to one metered seal unit. Once the topology seal
exists, observed owners temporarily write through exactly until activation,
so the finite pre-seal queue drains even when several unrelated owners move
continuously. Production activates in that same update-thread call. Slots older than a
newer draft's captured root are superseded at the tail rather than reused
behind live cursors; new drafts start at their captured suffix, obsolete
slots compact incrementally, and the journal clears with the last draft.
Empty prefix containers are reclaimed under GUID churn; seal cursors retain
their captured slot lists.
Cache, CellGraph, engine, and shadow topology share one complete off-side
`CollisionWorldState`. Admission captures the current root reference in O(1)
and materializes the non-target leaves through the same one-work-unit frame
meter; a dense resident world is never cloned synchronously. After an older
preparation commits, its exact landblock delta queues into every later draft
and drains one cache, graph, landblock, or owner leaf per seal step. A later
demotion or withdrawal cancels matching queued/active rebases and tombstones
that prefix in unfinished source scans, then retires one owner/cache/graph/
outdoor leaf per seal step from growable retirement storage. Commit rechecks
both retirement and rebase state after sealing, so retired topology cannot
return or cause a drafts-times-world-size update spike.
The host immediately performs the zero-work root transfer in the same update-
thread call that completes final reconciliation, so continuous unrelated
movement cannot manufacture a required quiet frame between seal and commit.
Deterministic preparation order prevents a later draft from exposing early,
inheriting cancelled topology, or overwriting a committed prefix. Final activation is one
zero-allocation volatile root transfer that preserves public facade identity,
revokes staging, and then emits `CollisionGenerationCommitted`. Cancellation disposes only the named
staging generation and never withdraws the previous active world. Thus
readers see the complete old generation or complete new generation, never a
mixed cell/cache/shadow world.
- `ShadowObjectRegistry` gives movement a per-cell broadphase over nearby
objects and buildings. Streaming reflood is structurally part of the Runtime
collision-generation commit; there is no independent post-publication