Added stackalloc where it's acceptable

src/DotRecast.Core/Buffers/RcRentedArray.cs

@@ -6,7 +6,7 @@ namespace DotRecast.Core.Buffers
 {
     public static class RcRentedArray
     {
-        public static RcRentedArray<T> Rent<T>(int minimumLength)
+        public static RcRentedArray<T> RentDisposableArray<T>(int minimumLength)
         {
             var array = ArrayPool<T>.Shared.Rent(minimumLength);
             return new RcRentedArray<T>(ArrayPool<T>.Shared, array, minimumLength);
@@ -17,41 +17,44 @@ namespace DotRecast.Core.Buffers
     {
         private ArrayPool<T> _owner;
         private T[] _array;
+        private readonly RcAtomicInteger _disposed;
 
         public int Length { get; }
-        public bool IsDisposed => null == _owner || null == _array;
 
         internal RcRentedArray(ArrayPool<T> owner, T[] array, int length)
         {
             _owner = owner;
             _array = array;
             Length = length;
+            _disposed = new RcAtomicInteger(0);
         }
 
-        public ref T this[int index]
+        public T this[int index]
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
             get
             {
                 RcThrowHelper.ThrowExceptionIfIndexOutOfRange(index, Length);
-                return ref _array[index];
-            }
+                return _array[index];
             }
 
-        public T[] AsArray()
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            set
             {
-            return _array;
+                RcThrowHelper.ThrowExceptionIfIndexOutOfRange(index, Length);
+                _array[index] = value;
+            }
         }
 
 
         public void Dispose()
         {
-            if (null != _owner && null != _array)
-            {
-                _owner.Return(_array, true);
-                _owner = null;
+            if (1 != _disposed.IncrementAndGet())
+                return;
+
+            _owner?.Return(_array, true);
             _array = null;
-            }
+            _owner = null;
         }
     }
 }

src/DotRecast.Detour.Crowd/DtCrowd.cs

@@ -168,7 +168,7 @@ namespace DotRecast.Detour.Crowd
             }
 
             // Allocate temp buffer for merging paths.
-            _maxPathResult = DtCrowdConst.MAX_PATH_RESULT;
+            _maxPathResult = 256;
             _pathQ = new DtPathQueue(config);
             _agents = new List<DtCrowdAgent>();
 

src/DotRecast.Detour.Crowd/DtCrowdConst.cs

@@ -30,6 +30,5 @@
         public const int MAX_ITERS_PER_UPDATE = 100;
         public const int MAX_PATHQUEUE_NODES = 4096;
         public const int MAX_COMMON_NODES = 512;
-        public const int MAX_PATH_RESULT = 256;
     }
 }

src/DotRecast.Detour.Crowd/DtPathCorridor.cs

@@ -215,7 +215,7 @@ namespace DotRecast.Detour.Crowd
             {
                 if (res.Count > 1 && t > 0.99f)
                 {
-                    m_path = DtPathUtils.MergeCorridorStartShortcut(m_path, m_path.Count, m_maxPath, res);
+                    m_path = DtPathUtils.MergeCorridorStartShortcut(m_path, m_maxPath, res);
                 }
             }
         }
@@ -241,13 +241,13 @@ namespace DotRecast.Detour.Crowd
             }
 
             var res = new List<long>();
-            navquery.InitSlicedFindPath(m_path[0], m_path[^1], m_pos, m_target, filter, 0);
+            navquery.InitSlicedFindPath(m_path[0], m_path[m_path.Count - 1], m_pos, m_target, filter, 0);
             navquery.UpdateSlicedFindPath(maxIterations, out var _);
             var status = navquery.FinalizeSlicedFindPathPartial(m_path, ref res);
 
             if (status.Succeeded() && res.Count > 0)
             {
-                m_path = DtPathUtils.MergeCorridorStartShortcut(m_path, m_path.Count, m_maxPath, res);
+                m_path = DtPathUtils.MergeCorridorStartShortcut(m_path, m_maxPath, res);
                 return true;
             }
 
@@ -316,7 +316,7 @@ namespace DotRecast.Detour.Crowd
             var status = navquery.MoveAlongSurface(m_path[0], m_pos, npos, filter, out var result, ref visited);
             if (status.Succeeded())
             {
-                m_path = DtPathUtils.MergeCorridorStartMoved(m_path, m_path.Count, m_maxPath, visited);
+                m_path = DtPathUtils.MergeCorridorStartMoved(m_path, m_maxPath, visited);
 
                 // Adjust the position to stay on top of the navmesh.
                 m_pos = result;
@@ -355,10 +355,10 @@ namespace DotRecast.Detour.Crowd
         {
             // Move along navmesh and update new position.
             var visited = new List<long>();
-            var status = navquery.MoveAlongSurface(m_path[^1], m_target, npos, filter, out var result, ref visited);
+            var status = navquery.MoveAlongSurface(m_path[m_path.Count - 1], m_target, npos, filter, out var result, ref visited);
             if (status.Succeeded())
             {
-                m_path = DtPathUtils.MergeCorridorEndMoved(m_path, m_path.Count, m_maxPath, visited);
+                m_path = DtPathUtils.MergeCorridorEndMoved(m_path, m_maxPath, visited);
                 // TODO: should we do that?
                 // Adjust the position to stay on top of the navmesh.
                 /*

src/DotRecast.Detour/DtNavMesh.cs

@@ -358,8 +358,8 @@ namespace DotRecast.Detour
                 var tbmax = tile.data.header.bmax;
                 float qfac = tile.data.header.bvQuantFactor;
                 // Calculate quantized box
-                int[] bmin = new int[3];
-                int[] bmax = new int[3];
+                Span<int> bmin = stackalloc int[3];
+                Span<int> bmax = stackalloc int[3];
                 // dtClamp query box to world box.
                 float minx = Math.Clamp(qmin.X, tbmin.X, tbmax.X) - tbmin.X;
                 float miny = Math.Clamp(qmin.Y, tbmin.Y, tbmax.Y) - tbmin.Y;

src/DotRecast.Detour/DtNavMeshQuery.cs

@@ -583,8 +583,8 @@ namespace DotRecast.Detour
                 var tbmax = tile.data.header.bmax;
                 float qfac = tile.data.header.bvQuantFactor;
                 // Calculate quantized box
-                int[] bmin = new int[3];
-                int[] bmax = new int[3];
+                Span<int> bmin = stackalloc int[3];
+                Span<int> bmax = stackalloc int[3];
                 // dtClamp query box to world box.
                 float minx = Math.Clamp(qmin.X, tbmin.X, tbmax.X) - tbmin.X;
                 float miny = Math.Clamp(qmin.Y, tbmin.Y, tbmax.Y) - tbmin.Y;
@@ -1824,6 +1824,9 @@ namespace DotRecast.Detour
 
             float[] verts = new float[m_nav.GetMaxVertsPerPoly() * 3];
 
+            const int MAX_NEIS = 8;
+            Span<long> neis = stackalloc long[MAX_NEIS];
+
             while (0 < stack.Count)
             {
                 // Pop front.
@@ -1854,9 +1857,7 @@ namespace DotRecast.Detour
                 for (int i = 0, j = curPoly.vertCount - 1; i < curPoly.vertCount; j = i++)
                 {
                     // Find links to neighbours.
-                    int MAX_NEIS = 8;
                     int nneis = 0;
-                    long[] neis = new long[MAX_NEIS];
 
                     if ((curPoly.neis[j] & DtNavMesh.DT_EXT_LINK) != 0)
                     {

src/DotRecast.Detour/DtPathUtils.cs

@@ -141,7 +141,7 @@ namespace DotRecast.Detour
             return path;
         }
 
-        public static List<long> MergeCorridorStartMoved(List<long> path, int npath, int maxPath, List<long> visited)
+        public static List<long> MergeCorridorStartMoved(List<long> path, int maxPath, List<long> visited)
         {
             int furthestPath = -1;
             int furthestVisited = -1;
@@ -186,7 +186,7 @@ namespace DotRecast.Detour
             return result;
         }
 
-        public static List<long> MergeCorridorEndMoved(List<long> path, int npath, int maxPath, List<long> visited)
+        public static List<long> MergeCorridorEndMoved(List<long> path, int maxPath, List<long> visited)
         {
             int furthestPath = -1;
             int furthestVisited = -1;
@@ -223,7 +223,7 @@ namespace DotRecast.Detour
             return result;
         }
 
-        public static List<long> MergeCorridorStartShortcut(List<long> path, int npath, int maxPath, List<long> visited)
+        public static List<long> MergeCorridorStartShortcut(List<long> path, int maxPath, List<long> visited)
         {
             int furthestPath = -1;
             int furthestVisited = -1;

src/DotRecast.Detour/DtUtils.cs

@@ -64,7 +64,7 @@ namespace DotRecast.Detour
         /// @param[in] bmax Maximum bounds of box B. [(x, y, z)]
         /// @return True if the two AABB's overlap.
         /// @see dtOverlapBounds
-        public static bool OverlapQuantBounds(int[] amin, int[] amax, int[] bmin, int[] bmax)
+        public static bool OverlapQuantBounds(Span<int> amin, Span<int> amax, Span<int> bmin, Span<int> bmax)
         {
             bool overlap = true;
             overlap = (amin[0] > bmax[0] || amax[0] < bmin[0]) ? false : overlap;

src/DotRecast.Recast.Toolset/Tools/RcTestNavMeshTool.cs

@@ -92,7 +92,7 @@ namespace DotRecast.Recast.Toolset.Tools
 
                 iterPos = result;
 
-                pathIterPolys = DtPathUtils.MergeCorridorStartMoved(pathIterPolys, pathIterPolys.Count, MAX_POLYS, visited);
+                pathIterPolys = DtPathUtils.MergeCorridorStartMoved(pathIterPolys, MAX_POLYS, visited);
                 pathIterPolys = DtPathUtils.FixupShortcuts(pathIterPolys, navQuery);
 
                 var status = navQuery.GetPolyHeight(pathIterPolys[0], result, out var h);

test/DotRecast.Core.Test/RcArrayBenchmarkTests.cs

@@ -1,101 +0,0 @@
-using System;
-using System.Buffers;
-using System.Collections.Generic;
-using DotRecast.Core.Buffers;
-using DotRecast.Core.Collections;
-using NUnit.Framework;
-
-namespace DotRecast.Core.Test;
-
-public class RcArrayBenchmarkTests
-{
-    private const int StepLength = 512;
-    private const int RandomLoop = 1000;
-    private readonly RcRand _rand = new RcRand();
-
-    private (string title, long ticks) Bench(string title, Action<int> source)
-    {
-        var begin = RcFrequency.Ticks;
-        for (int step = StepLength; step > 0; --step)
-        {
-            for (int i = 0; i < RandomLoop; ++i)
-            {
-                source.Invoke(step);
-            }
-        }
-
-        var end = RcFrequency.Ticks - begin;
-        return (title, end);
-    }
-
-
-    private void RoundForArray(int len)
-    {
-        var array = new int[len];
-        for (int ii = 0; ii < len; ++ii)
-        {
-            array[ii] = _rand.NextInt32();
-        }
-    }
-
-
-    private void RoundForPureRentArray(int len)
-    {
-        var array = ArrayPool<int>.Shared.Rent(len);
-        for (int ii = 0; ii < array.Length; ++ii)
-        {
-            array[ii] = _rand.NextInt32();
-        }
-
-        ArrayPool<int>.Shared.Return(array);
-    }
-
-
-    private void RoundForRcRentedArray(int len)
-    {
-        using var rentedArray = RcRentedArray.Rent<int>(len);
-        var array = rentedArray.AsArray();
-        for (int i = 0; i < rentedArray.Length; ++i)
-        {
-            array[i] = _rand.NextInt32();
-        }
-    }
-
-
-    private void RoundForRcStackArray(int len)
-    {
-        var array = new RcStackArray512<int>();
-        for (int ii = 0; ii < len; ++ii)
-        {
-            array[ii] = _rand.NextInt32();
-        }
-    }
-
-    private void RoundForStackalloc(int len)
-    {
-        Span<int> array = stackalloc int[len];
-        for (int ii = 0; ii < len; ++ii)
-        {
-            array[ii] = _rand.NextInt32();
-        }
-    }
-
-
-    [Test]
-    public void TestBenchmarkArrays()
-    {
-        var list = new List<(string title, long ticks)>();
-        list.Add(Bench("new int[len]", RoundForArray));
-        list.Add(Bench("ArrayPool<int>.Shared.Rent(len)", RoundForPureRentArray));
-        list.Add(Bench("RcRentedArray.Rent<int>(len)", RoundForRcRentedArray));
-        list.Add(Bench("new RcStackArray512<int>()", RoundForRcStackArray));
-        list.Add(Bench("stackalloc int[len]", RoundForStackalloc));
-
-        list.Sort((x, y) => x.ticks.CompareTo(y.ticks));
-
-        foreach (var t in list)
-        {
-            Console.WriteLine($"{t.title} {t.ticks / (double)TimeSpan.TicksPerMillisecond} ms");
-        }
-    }
-}

test/DotRecast.Core.Test/RcRentedArrayTest.cs

@@ -31,7 +31,7 @@ public class RcRentedArrayTest
             {
                 int length = Math.Max(2, (int)(rand.Next() * 2048));
                 var values = RandomValues(length);
-                using var array = RcRentedArray.Rent<int>(length);
+                using var array = RcRentedArray.RentDisposableArray<int>(length);
 
                 for (int i = 0; i < array.Length; ++i)
                 {