Pr/various mem optimizations

src/DotRecast.Core/Buffers/RcObjectPool.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+
+namespace DotRecast.Core.Buffers
+{
+    // This implementation is thread unsafe
+    public class RcObjectPool<T> where T : class
+    {
+        private readonly Queue<T> _items = new Queue<T>();
+        private readonly Func<T> _createFunc;
+
+        public RcObjectPool(Func<T> createFunc)
+        {
+            _createFunc = createFunc;
+        }
+
+        public T Get()
+        {
+            if (_items.TryDequeue(out var result))
+                return result;
+
+            return _createFunc();
+        }
+
+        public void Return(T obj)
+        {
+            _items.Enqueue(obj);
+        }
+    }
+}

src/DotRecast.Core/Buffers/RcRentedArray.cs

@@ -1,31 +1,96 @@
-using System;
+using System;
 using System.Buffers;
+using System.Collections.Generic;
 using System.Runtime.CompilerServices;
+using System.Threading;
 
 namespace DotRecast.Core.Buffers
 {
     public static class RcRentedArray
     {
+        private sealed class RentIdPool
+        {
+            private int[] _generations;
+            private readonly Queue<int> _freeIds;
+            private int _maxId;
+
+            public RentIdPool(int capacity)
+            {
+                _generations = new int[capacity];
+                _freeIds = new Queue<int>(capacity);
+            }
+
+            internal RentIdGen AcquireId()
+            {
+                if (!_freeIds.TryDequeue(out int id))
+                {
+                    id = _maxId++;
+                    if(_generations.Length <= id)
+                        Array.Resize(ref _generations, _generations.Length << 1);    
+                }
+
+                return new RentIdGen(id, _generations[id]);
+            }
+
+            internal void ReturnId(int id)
+            {
+                _generations[id]++;
+                _freeIds.Enqueue(id);
+            }
+
+            internal int GetGeneration(int id)
+            {
+                return _generations.Length <= id ? 0 : _generations[id];
+            }
+        }
+
+        public const int START_RENT_ID_POOL_CAPACITY = 16;
+        private static readonly ThreadLocal<RentIdPool> _rentPool = new ThreadLocal<RentIdPool>(() => new RentIdPool(START_RENT_ID_POOL_CAPACITY));
+
         public static RcRentedArray<T> Rent<T>(int minimumLength)
         {
             var array = ArrayPool<T>.Shared.Rent(minimumLength);
-            return new RcRentedArray<T>(ArrayPool<T>.Shared, array, minimumLength);
+            return new RcRentedArray<T>(ArrayPool<T>.Shared, _rentPool.Value.AcquireId(), array, minimumLength);
+        }
+
+        internal static bool IsDisposed(RentIdGen rentIdGen)
+        {
+            return _rentPool.Value.GetGeneration(rentIdGen.Id) != rentIdGen.Gen;
+        }
+
+        internal static void ReturnId(RentIdGen rentIdGen)
+        {
+            _rentPool.Value.ReturnId(rentIdGen.Id);
         }
     }
 
-    public class RcRentedArray<T> : IDisposable
+    public readonly struct RentIdGen
+    {
+        public readonly int Id;
+        public readonly int Gen;
+
+        public RentIdGen(int id, int gen)
+        {
+            Id = id;
+            Gen = gen;
+        }
+    }
+
+    public struct RcRentedArray<T> : IDisposable
     {
         private ArrayPool<T> _owner;
         private T[] _array;
+        private readonly RentIdGen _rentIdGen;
 
         public int Length { get; }
-        public bool IsDisposed => null == _owner || null == _array;
+        public bool IsDisposed => null == _owner || null == _array || RcRentedArray.IsDisposed(_rentIdGen);
 
-        internal RcRentedArray(ArrayPool<T> owner, T[] array, int length)
+        internal RcRentedArray(ArrayPool<T> owner, RentIdGen rentIdGen, T[] array, int length)
         {
             _owner = owner;
             _array = array;
             Length = length;
+            _rentIdGen = rentIdGen;
         }
 
         public ref T this[int index]
@@ -34,6 +99,8 @@ public ref T this[int index]
             get
             {
                 RcThrowHelper.ThrowExceptionIfIndexOutOfRange(index, Length);
+                if (IsDisposed)
+                    throw new NullReferenceException();
                 return ref _array[index];
             }
         }
@@ -43,15 +110,22 @@ public T[] AsArray()
             return _array;
         }
 
+        public Span<T> AsSpan()
+        {
+            return new Span<T>(_array, 0, Length);
+        }
+
 
         public void Dispose()
         {
-            if (null != _owner && null != _array)
+            if (null != _owner && null != _array && !RcRentedArray.IsDisposed(_rentIdGen))
             {
+                RcRentedArray.ReturnId(_rentIdGen);
                 _owner.Return(_array, true);
-                _owner = null;
-                _array = null;
             }
+
+            _owner = null;
+            _array = null;
         }
     }
 }

src/DotRecast.Core/Collections/CollectionExtensions.cs

@@ -45,5 +45,11 @@ public static void Shuffle<T>(this IList<T> list)
                 (list[k], list[n]) = (list[n], list[k]);
             }
         }
+
+        public static void AddRange<T>(this IList<T> list, Span<T> span)
+        {
+            foreach (var i in span) 
+                list.Add(i);
+        }
     }
 }

src/DotRecast.Core/Collections/RcSortedQueue.cs

@@ -27,12 +27,12 @@ public class RcSortedQueue<T>
     {
         private bool _dirty;
         private readonly List<T> _items;
-        private readonly Comparer<T> _comparer;
+        private readonly Comparison<T> _comparison;
 
         public RcSortedQueue(Comparison<T> comp)
         {
             _items = new List<T>();
-            _comparer = Comparer<T>.Create((x, y) => comp.Invoke(x, y) * -1);
+            _comparison = (x, y) => comp(x, y) * -1;
         }
 
         public int Count()
@@ -55,7 +55,7 @@ private void Balance()
         {
             if (_dirty)
             {
-                _items.Sort(_comparer); // reverse
+                _items.Sort(_comparison); // reverse
                 _dirty = false;
             }
         }
@@ -88,7 +88,7 @@ public bool Remove(T item)
                 return false;
 
             //int idx = _items.BinarySearch(item, _comparer); // don't use this! Because reference types can be reused externally.
-            int idx = _items.FindLastIndex(x => item.Equals(x));
+            int idx = _items.LastIndexOf(item);
             if (0 > idx)
                 return false;
 

src/DotRecast.Core/Numerics/RcVec.cs

@@ -205,7 +205,7 @@ public static float Dist2DSqr(RcVec3f v1, RcVec3f v2)
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static float Dist2DSqr(RcVec3f p, float[] verts, int i)
+        public static float Dist2DSqr(RcVec3f p, Span<float> verts, int i)
         {
             float dx = verts[i] - p.X;
             float dz = verts[i + 2] - p.Z;

src/DotRecast.Detour.Crowd/DtCrowd.cs

@@ -129,7 +129,7 @@ public class DtCrowd
         private readonly DtObstacleAvoidanceParams[] _obstacleQueryParams;
         private readonly DtObstacleAvoidanceQuery _obstacleQuery;
 
-        private DtProximityGrid _grid;
+        private readonly DtProximityGrid _grid;
 
         private int _maxPathResult;
         private readonly RcVec3f _agentPlacementHalfExtents;
@@ -174,6 +174,7 @@ public DtCrowd(DtCrowdConfig config, DtNavMesh nav, Func<int, IDtQueryFilter> qu
             _agentIdx = new RcAtomicInteger(0);
             _agents = new Dictionary<int, DtCrowdAgent>();
             _activeAgents = new List<DtCrowdAgent>();
+            _grid = new DtProximityGrid(_config.maxAgentRadius * 3);
 
             // The navQuery is mostly used for local searches, no need for large node pool.
             SetNavMesh(nav);
@@ -564,14 +565,18 @@ private void CheckPathValidity(IList<DtCrowdAgent> agents, float dt)
             }
         }
 
+        private readonly RcSortedQueue<DtCrowdAgent> UpdateMoveRequest_queue = new RcSortedQueue<DtCrowdAgent>((a1, a2) => a2.targetReplanTime.CompareTo(a1.targetReplanTime));
+        private readonly List<long> UpdateMoveRequest_reqPath = new List<long>();
         private void UpdateMoveRequest(IList<DtCrowdAgent> agents, float dt)
         {
             using var timer = _telemetry.ScopedTimer(DtCrowdTimerLabel.UpdateMoveRequest);
 
-            RcSortedQueue<DtCrowdAgent> queue = new RcSortedQueue<DtCrowdAgent>((a1, a2) => a2.targetReplanTime.CompareTo(a1.targetReplanTime));
+            RcSortedQueue<DtCrowdAgent> queue = UpdateMoveRequest_queue;
+            queue.Clear();
 
             // Fire off new requests.
-            List<long> reqPath = new List<long>();
+            List<long> reqPath = UpdateMoveRequest_reqPath;
+            reqPath.Clear();
             for (var i = 0; i < agents.Count; i++)
             {
                 var ag = agents[i];
@@ -864,7 +869,7 @@ private void BuildProximityGrid(IList<DtCrowdAgent> agents)
         {
             using var timer = _telemetry.ScopedTimer(DtCrowdTimerLabel.BuildProximityGrid);
 
-            _grid = new DtProximityGrid(_config.maxAgentRadius * 3);
+            _grid.Clear();
 
             for (var i = 0; i < agents.Count; i++)
             {

src/DotRecast.Detour.Crowd/DtPathCorridor.cs

@@ -33,7 +33,7 @@ public class DtPathCorridor
         private RcVec3f m_pos;
         private RcVec3f m_target;
 
-        private List<long> m_path;
+        private List<long> m_path = new List<long>();
         private int m_npath;
         private int m_maxPath;
 
@@ -89,7 +89,8 @@ public DtPathCorridor()
         /// @return True if the initialization succeeded.
         public bool Init(int maxPath)
         {
-            m_path = new List<long>(maxPath);
+            if (m_path.Capacity < maxPath)
+                m_path.Capacity = maxPath;
             m_npath = 0;
             m_maxPath = maxPath;
             return true;
@@ -218,7 +219,7 @@ public void OptimizePathVisibility(RcVec3f next, float pathOptimizationRange, Dt
             {
                 if (res.Count > 1 && t > 0.99f)
                 {
-                    m_npath = DtPathUtils.MergeCorridorStartShortcut(ref m_path, m_npath, m_maxPath, res, res.Count);
+                    m_npath = DtPathUtils.MergeCorridorStartShortcut(m_path, m_npath, m_maxPath, res, res.Count);
                 }
             }
         }
@@ -250,7 +251,7 @@ public bool OptimizePathTopology(DtNavMeshQuery navquery, IDtQueryFilter filter,
 
             if (status.Succeeded() && res.Count > 0)
             {
-                m_npath = DtPathUtils.MergeCorridorStartShortcut(ref m_path, m_npath, m_maxPath, res, res.Count);
+                m_npath = DtPathUtils.MergeCorridorStartShortcut(m_path, m_npath, m_maxPath, res, res.Count);
                 return true;
             }
 
@@ -276,7 +277,7 @@ public bool MoveOverOffmeshConnection(long offMeshConRef, long[] refs, ref RcVec
             }
 
             // Prune path
-            m_path = m_path.GetRange(npos, m_npath - npos);
+            m_path.RemoveRange(0, npos);
             m_npath -= npos;
 
             refs[0] = prevRef;
@@ -322,7 +323,7 @@ public bool MovePosition(RcVec3f npos, DtNavMeshQuery navquery, IDtQueryFilter f
             var status = navquery.MoveAlongSurface(m_path[0], m_pos, npos, filter, out var result, visited, out var nvisited, MAX_VISITED);
             if (status.Succeeded())
             {
-                m_npath = DtPathUtils.MergeCorridorStartMoved(ref m_path, m_npath, m_maxPath, visited, nvisited);
+                m_npath = DtPathUtils.MergeCorridorStartMoved(m_path, m_npath, m_maxPath, visited, nvisited);
 
                 // Adjust the position to stay on top of the navmesh.
                 m_pos = result;
@@ -366,7 +367,7 @@ public bool MoveTargetPosition(RcVec3f npos, DtNavMeshQuery navquery, IDtQueryFi
             var status = navquery.MoveAlongSurface(m_path[^1], m_target, npos, filter, out var result, visited, out nvisited, MAX_VISITED);
             if (status.Succeeded())
             {
-                m_npath = DtPathUtils.MergeCorridorEndMoved(ref m_path, m_npath, m_maxPath, visited, nvisited);
+                m_npath = DtPathUtils.MergeCorridorEndMoved(m_path, m_npath, m_maxPath, visited, nvisited);
 
                 // TODO: should we do that?
                 // Adjust the position to stay on top of the navmesh.
@@ -394,7 +395,11 @@ public bool MoveTargetPosition(RcVec3f npos, DtNavMeshQuery navquery, IDtQueryFi
         public void SetCorridor(RcVec3f target, List<long> path)
         {
             m_target = target;
-            m_path = new List<long>(path);
+            if(path != m_path)
+            {
+                m_path.Clear();
+                m_path.AddRange(path);
+            }
             m_npath = path.Count;
         }
 
@@ -444,7 +449,7 @@ public bool TrimInvalidPath(long safeRef, float[] safePos, DtNavMeshQuery navque
             else if (n < m_npath)
             {
                 // The path is partially usable.
-                m_path = m_path.GetRange(0, n);
+                m_path.RemoveRange(n, m_path.Count - n);
                 m_npath = n;
             }
 

src/DotRecast.Detour.Crowd/DtProximityGrid.cs

@@ -22,6 +22,7 @@ 3. This notice may not be removed or altered from any source distribution.
 using System.Collections.Generic;
 using System.Linq;
 using System.Runtime.CompilerServices;
+using DotRecast.Core.Buffers;
 
 namespace DotRecast.Detour.Crowd
 {
@@ -30,12 +31,14 @@ public class DtProximityGrid
         private readonly float _cellSize;
         private readonly float _invCellSize;
         private readonly Dictionary<long, List<DtCrowdAgent>> _items;
+        private readonly RcObjectPool<List<DtCrowdAgent>> _listPool;
 
         public DtProximityGrid(float cellSize)
         {
             _cellSize = cellSize;
             _invCellSize = 1.0f / cellSize;
             _items = new Dictionary<long, List<DtCrowdAgent>>();
+            _listPool = new RcObjectPool<List<DtCrowdAgent>>(() => new List<DtCrowdAgent>());
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -57,6 +60,8 @@ public static void DecomposeKey(long key, out int x, out int y)
 
         public void Clear()
         {
+            foreach (var pair in _items)
+                _listPool.Return(pair.Value);
             _items.Clear();
         }
 
@@ -74,7 +79,8 @@ public void AddItem(DtCrowdAgent agent, float minx, float miny, float maxx, floa
                     long key = CombineKey(x, y);
                     if (!_items.TryGetValue(key, out var ids))
                     {
-                        ids = new List<DtCrowdAgent>();
+                        ids = _listPool.Get();
+                        ids.Clear();
                         _items.Add(key, ids);
                     }