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Another pass

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This commit is contained in:
Fr0zka
2026-06-23 08:30:13 +02:00
parent db558d9e14
commit e6cd852129
17 changed files with 2340 additions and 878 deletions
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Source/VoxelForge/Private/VoxelDiffLayer.cpp
+35 -9
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@@ -95,21 +95,28 @@ TArray<FIntVector> UVoxelDiffLayer::ApplyModification(const FVoxelModification&
const int32 MinCZ = FMath::FloorToInt(BoundsMin.Z / CHUNK_SIZE);
const int32 MaxCZ = FMath::FloorToInt(BoundsMax.Z / CHUNK_SIZE);
for (int32 CZ = MinCZ; CZ <= MaxCZ; CZ++)
{
for (int32 CY = MinCY; CY <= MaxCY; CY++)
// Write lock: blocks worker-thread readers (HasModifications / GetDensityOffset) while the map
// is mutated/rehashed. AffectedChunks is local; populate it in the same pass.
FWriteScopeLock Lock(ModsLock);
for (int32 CZ = MinCZ; CZ <= MaxCZ; CZ++)
{
for (int32 CX = MinCX; CX <= MaxCX; CX++)
for (int32 CY = MinCY; CY <= MaxCY; CY++)
{
FIntVector ChunkCoord(CX, CY, CZ);
for (int32 CX = MinCX; CX <= MaxCX; CX++)
{
FIntVector ChunkCoord(CX, CY, CZ);
// Store the modification in this chunk's list
ChunkMods.FindOrAdd(ChunkCoord).Add(ClampedMod);
// Store the modification in this chunk's list
ChunkMods.FindOrAdd(ChunkCoord).Add(ClampedMod);
// Track which chunks need re-meshing
AffectedChunks.Add(ChunkCoord);
// Track which chunks need re-meshing
AffectedChunks.Add(ChunkCoord);
}
}
}
// Publish: subsequent readers must now take the lock instead of fast-rejecting.
bHasAnyMods.store(true, std::memory_order_release);
}
UE_LOG(LogTemp, Log,
@@ -131,6 +138,13 @@ TArray<FIntVector> UVoxelDiffLayer::ApplyModification(const FVoxelModification&
float UVoxelDiffLayer::GetDensityOffset(const FIntVector& ChunkCoord,
float WorldX, float WorldY, float WorldZ) const
{
// Lock-free fast reject: no carves anywhere -> nothing to offset.
if (!bHasAnyMods.load(std::memory_order_acquire)) return 0.0f;
// Hold the read lock for the whole body: Mods points INTO the map and is dereferenced through the
// falloff loop below, so the map must not be rehashed by a concurrent writer meanwhile.
FReadScopeLock Lock(ModsLock);
// Fast path: if this chunk has no modifications, return 0
const TArray<FVoxelModification>* Mods = ChunkMods.Find(ChunkCoord);
if (!Mods || Mods->Num() == 0) return 0.0f;
@@ -194,6 +208,10 @@ float UVoxelDiffLayer::GetDensityOffset(const FIntVector& ChunkCoord,
bool UVoxelDiffLayer::HasModifications(const FIntVector& ChunkCoord) const
{
// Lock-free fast reject: no carves anywhere -> the map is empty, skip lock + lookup entirely.
if (!bHasAnyMods.load(std::memory_order_acquire)) return false;
FReadScopeLock Lock(ModsLock); // worker threads read concurrently; serialised vs. writers
const TArray<FVoxelModification>* Mods = ChunkMods.Find(ChunkCoord);
return Mods && Mods->Num() > 0;
}
@@ -205,7 +223,13 @@ bool UVoxelDiffLayer::HasModifications(const FIntVector& ChunkCoord) const
void UVoxelDiffLayer::Clear()
{
int32 Count = GetTotalModificationCount();
ChunkMods.Empty();
{
// Write lock: workers may be mid-read. Flip the fast-path flag false BEFORE emptying so any
// reader that loads it afterwards skips the map without locking.
FWriteScopeLock Lock(ModsLock);
bHasAnyMods.store(false, std::memory_order_release);
ChunkMods.Empty();
}
// Reset budget counters — player gets a fresh budget after clear/season reset
ModificationCount = 0;
@@ -216,6 +240,7 @@ void UVoxelDiffLayer::Clear()
int32 UVoxelDiffLayer::GetTotalModificationCount() const
{
FReadScopeLock Lock(ModsLock);
int32 Total = 0;
for (const auto& Pair : ChunkMods)
{
@@ -226,5 +251,6 @@ int32 UVoxelDiffLayer::GetTotalModificationCount() const
int32 UVoxelDiffLayer::GetModifiedChunkCount() const
{
FReadScopeLock Lock(ModsLock);
return ChunkMods.Num();
}