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fix(render #53): key cache by (entityId, landblockHint) to defeat ID collision

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User confirmed via A/B test (ACDREAM_DISABLE_TIER1_CACHE=1) that the
visual bug — buildings rendering up in the air outside Holtburg — is in
the cache wiring, not elsewhere. The matrix math (restPose * entityWorld
== model) was provably correct, so the bug had to be cache key collision.

Stabs were namespaced in commit 71d0edc, but scenery (0x80LLBB00 +
localIndex) and interior (0x40LLBB00 + localCounter) still have the
same 256-overflow risk. Dense LBs outside Holtburg (forest, urban) push
localIndex past 255, wrapping into the lbY byte and creating cross-LB
collisions.

Fix: change the cache key from uint entityId to (uint, uint) tuple of
(EntityId, LandblockHint). The cache is now correct-by-construction
regardless of any hydration path's Id-generation strategy. Defensive
against future regressions in any ID namespace.

InvalidateEntity becomes a sweep (was O(1)), but it's called rarely
(only on live-entity despawn). InvalidateLandblock was already a sweep.

Updated 14 existing cache tests + 1 dispatcher integration test to thread
landblockHint through TryGet / DebugCrossCheck calls.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Erik 2026-05-10 23:02:14 +02:00
parent 71d0edc3d7
commit 95ebbf3004
4 changed files with 78 additions and 49 deletions
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14
tests/AcDream.Core.Tests/Rendering/Wb/WbDrawDispatcherBucketingTests.cs
View file

@ -428,7 +428,7 @@ public sealed class WbDrawDispatcherBucketingTests
// First-frame post-conditions: 1 cache entry, 2 batches in it.
Assert.Equal(1, cache.Count);
Assert.True(cache.TryGet(EntityId, out var entry));
Assert.True(cache.TryGet(EntityId, LandblockId, out var entry));
Assert.NotNull(entry);
Assert.Equal(2, entry!.Batches.Length);
Assert.Equal(0xAAul, entry.Batches[0].BindlessTextureHandle);
@ -449,7 +449,7 @@ public sealed class WbDrawDispatcherBucketingTests
list.Add(m);
}
Assert.True(cache.TryGet(EntityId, out var entryHit));
Assert.True(cache.TryGet(EntityId, LandblockId, out var entryHit));
Assert.NotNull(entryHit);
var entityWorld = Matrix4x4.CreateTranslation(new Vector3(10f, 20f, 30f));
WbDrawDispatcher.ApplyCacheHit(entryHit!, entityWorld, AppendInstance);
@ -510,11 +510,7 @@ public sealed class WbDrawDispatcherBucketingTests
// Cache should never be populated for animated entities.
Assert.Equal(0, cache.Count);
Assert.False(cache.TryGet(AnimatedId, out _));
// Suppress unused-variable warning — LandblockId is here for parity
// with the static-entity test's structure.
_ = LandblockId;
Assert.False(cache.TryGet(AnimatedId, LandblockId, out _));
}
[Fact]
@ -589,7 +585,7 @@ public sealed class WbDrawDispatcherBucketingTests
// Assertions: ONE cache entry with ALL 6 batches in MeshRef order.
Assert.Equal(1, cache.Count);
Assert.True(cache.TryGet(EntityId, out var entry));
Assert.True(cache.TryGet(EntityId, LandblockId, out var entry));
Assert.NotNull(entry);
Assert.Equal(EntityId, entry!.EntityId);
Assert.Equal(LandblockId, entry.LandblockHint);
@ -667,7 +663,7 @@ public sealed class WbDrawDispatcherBucketingTests
// Skip subsequent tuples of an entity that cache-hit (the fix).
if (lastHitEntityId == EntityId) continue;
if (cache.TryGet(EntityId, out var entry))
if (cache.TryGet(EntityId, 0xA9B40000u, out var entry))
{
Assert.NotNull(entry);
WbDrawDispatcher.ApplyCacheHit(entry!, entityWorld, AppendInstance);