From ed5ad91a32cc6b4d01410a86e12f20ba6ee42243 Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Sat, 7 Feb 2026 00:46:32 +0100
Subject: [PATCH] Optimize `SkinnedModel::GetSkeletonMapping` to not use
 locking for better perf when multi-threading

#3827
---
 Source/Engine/Content/Assets/SkinnedModel.cpp | 27 ++++++++++++-------
 Source/Engine/Content/Assets/SkinnedModel.h   |  8 +++---
 2 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/Source/Engine/Content/Assets/SkinnedModel.cpp b/Source/Engine/Content/Assets/SkinnedModel.cpp
index ed41c4aab..ce6300b17 100644
--- a/Source/Engine/Content/Assets/SkinnedModel.cpp
+++ b/Source/Engine/Content/Assets/SkinnedModel.cpp
@@ -61,16 +61,24 @@ Array<String> SkinnedModel::GetBlendShapes()
 
 SkinnedModel::SkeletonMapping SkinnedModel::GetSkeletonMapping(Asset* source, bool autoRetarget)
 {
+    // Fast-path to use cached mapping
     SkeletonMapping mapping;
     mapping.TargetSkeleton = this;
+    SkeletonMappingData mappingData;
+    if (_skeletonMappingCache.TryGet(source, mappingData))
+    {
+        mapping.SourceSkeleton = mappingData.SourceSkeleton;
+        mapping.NodesMapping = mappingData.NodesMapping;
+        return mapping;
+    }
+    mapping.SourceSkeleton = nullptr;
+
     if (WaitForLoaded() || !source || source->WaitForLoaded())
         return mapping;
+    PROFILE_CPU();
     ScopeLock lock(Locker);
-    SkeletonMappingData mappingData;
     if (!_skeletonMappingCache.TryGet(source, mappingData))
     {
-        PROFILE_CPU();
-
         // Initialize the mapping
         SkeletonRetarget* retarget = nullptr;
         const Guid sourceId = source->GetID();
@@ -823,13 +831,13 @@ bool SkinnedModel::SaveMesh(WriteStream& stream, const ModelData& modelData, int
 
 void SkinnedModel::ClearSkeletonMapping()
 {
-    for (auto& e : _skeletonMappingCache)
+    for (const auto& e : _skeletonMappingCache)
     {
         e.Key->OnUnloaded.Unbind<SkinnedModel, &SkinnedModel::OnSkeletonMappingSourceAssetUnloaded>(this);
 #if USE_EDITOR
         e.Key->OnReloading.Unbind<SkinnedModel, &SkinnedModel::OnSkeletonMappingSourceAssetUnloaded>(this);
 #endif
-        Allocator::Free(e.Value.NodesMapping.Get());
+        Allocator::Free((void*)e.Value.NodesMapping.Get());
     }
     _skeletonMappingCache.Clear();
 }
@@ -837,8 +845,9 @@ void SkinnedModel::ClearSkeletonMapping()
 void SkinnedModel::OnSkeletonMappingSourceAssetUnloaded(Asset* obj)
 {
     ScopeLock lock(Locker);
-    auto i = _skeletonMappingCache.Find(obj);
-    ASSERT(i != _skeletonMappingCache.End());
+    SkeletonMappingData mappingData;
+    bool found = _skeletonMappingCache.TryGet(obj, mappingData);
+    ASSERT(found);
 
     // Unlink event
     obj->OnUnloaded.Unbind<SkinnedModel, &SkinnedModel::OnSkeletonMappingSourceAssetUnloaded>(this);
@@ -847,8 +856,8 @@ void SkinnedModel::OnSkeletonMappingSourceAssetUnloaded(Asset* obj)
 #endif
 
     // Clear cache
-    Allocator::Free(i->Value.NodesMapping.Get());
-    _skeletonMappingCache.Remove(i);
+    Allocator::Free(mappingData.NodesMapping.Get());
+    _skeletonMappingCache.Remove(obj);
 }
 
 uint64 SkinnedModel::GetMemoryUsage() const
diff --git a/Source/Engine/Content/Assets/SkinnedModel.h b/Source/Engine/Content/Assets/SkinnedModel.h
index 894a080c4..111d4d6cb 100644
--- a/Source/Engine/Content/Assets/SkinnedModel.h
+++ b/Source/Engine/Content/Assets/SkinnedModel.h
@@ -3,7 +3,7 @@
 #pragma once
 
 #include "ModelBase.h"
-#include "Engine/Core/Collections/Dictionary.h"
+#include "Engine/Threading/ConcurrentDictionary.h"
 #include "Engine/Graphics/Models/SkinnedMesh.h"
 #include "Engine/Graphics/Models/SkeletonData.h"
 
@@ -101,9 +101,9 @@ public:
     struct FLAXENGINE_API SkeletonMapping
     {
         // Target skeleton.
-        AssetReference<SkinnedModel> TargetSkeleton;
+        SkinnedModel* TargetSkeleton;
         // Source skeleton.
-        AssetReference<SkinnedModel> SourceSkeleton;
+        SkinnedModel* SourceSkeleton;
         // The node-to-node mapping for the fast animation sampling for the skinned model skeleton nodes. Each item is index of the source skeleton node into target skeleton node.
         Span<int32> NodesMapping;
     };
@@ -115,7 +115,7 @@ private:
         Span<int32> NodesMapping;
     };
 
-    Dictionary<Asset*, SkeletonMappingData> _skeletonMappingCache;
+    ConcurrentDictionary<Asset*, SkeletonMappingData> _skeletonMappingCache;
 
 public:
     /// <summary>