SOH #41

src/DotRecast.Detour.Crowd/DtPathCorridor.cs

@@ -317,11 +317,12 @@ namespace DotRecast.Detour.Crowd
         public bool MovePosition(RcVec3f npos, DtNavMeshQuery navquery, IDtQueryFilter filter)
         {
             // Move along navmesh and update new position.
-            var visited = new List<long>();
+            const int MAX_VISITED = 16;
-            var status = navquery.MoveAlongSurface(m_path[0], m_pos, npos, filter, out var result, ref visited);
+            Span<long> visited = stackalloc long[MAX_VISITED];
+            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, visited.Count);
+                m_npath = DtPathUtils.MergeCorridorStartMoved(ref m_path, m_npath, m_maxPath, visited, nvisited);
 
                 // Adjust the position to stay on top of the navmesh.
                 m_pos = result;
@@ -359,11 +360,13 @@ namespace DotRecast.Detour.Crowd
         public bool MoveTargetPosition(RcVec3f npos, DtNavMeshQuery navquery, IDtQueryFilter filter)
         {
             // Move along navmesh and update new position.
-            var visited = new List<long>();
+            const int MAX_VISITED = 16;
-            var status = navquery.MoveAlongSurface(m_path[^1], m_target, npos, filter, out var result, ref visited);
+            Span<long> visited = stackalloc long[MAX_VISITED];
+            int nvisited = 0;
+            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, visited.Count);
+                m_npath = DtPathUtils.MergeCorridorEndMoved(ref m_path, m_npath, m_maxPath, visited, nvisited);
 
                 // TODO: should we do that?
                 // Adjust the position to stay on top of the navmesh.

src/DotRecast.Detour/DtNavMeshQuery.cs

@@ -1790,12 +1790,11 @@ namespace DotRecast.Detour
         /// @returns The status flags for the query.
         public DtStatus MoveAlongSurface(long startRef, RcVec3f startPos, RcVec3f endPos,
             IDtQueryFilter filter,
-            out RcVec3f resultPos, ref List<long> visited)
+            out RcVec3f resultPos, Span<long> visited, out int visitedCount, int maxVisitedSize)
         {
             resultPos = RcVec3f.Zero;
 
-            if (null != visited)
+            visitedCount = 0;
-                visited.Clear();
 
             // Validate input
             if (!m_nav.IsValidPolyRef(startRef) || !startPos.IsFinite()
@@ -1804,6 +1803,8 @@ namespace DotRecast.Detour
                 return DtStatus.DT_FAILURE | DtStatus.DT_INVALID_PARAM;
             }
 
+            DtStatus status = DtStatus.DT_SUCCESS;
+
             m_tinyNodePool.Clear();
 
             DtNode startNode = m_tinyNodePool.GetNode(startRef);
@@ -1938,6 +1939,7 @@ namespace DotRecast.Detour
                 }
             }
 
+            int n = 0;
             if (bestNode != null)
             {
                 // Reverse the path.
@@ -1955,14 +1957,21 @@ namespace DotRecast.Detour
                 node = prev;
                 do
                 {
-                    visited.Add(node.id);
+                    visited[n++] = node.id;
+                    if (n >= maxVisitedSize)
+                    {
+                        status |= DtStatus.DT_BUFFER_TOO_SMALL;;
+                        break;
+                    }
+
                     node = m_tinyNodePool.GetNodeAtIdx(node.pidx);
                 } while (node != null);
             }
 
             resultPos = bestPos;
+            visitedCount = n;
 
-            return DtStatus.DT_SUCCESS;
+            return status;
         }
 
         protected DtStatus GetPortalPoints(long from, long to, out RcVec3f left, out RcVec3f right, out int fromType, out int toType)

src/DotRecast.Detour/DtPathUtils.cs

@@ -146,7 +146,7 @@ namespace DotRecast.Detour
             return npath;
         }
 
-        public static int MergeCorridorStartMoved(ref List<long> path, int npath, int maxPath, List<long> visited, int nvisited)
+        public static int MergeCorridorStartMoved(ref List<long> path, int npath, int maxPath, Span<long> visited, int nvisited)
         {
             int furthestPath = -1;
             int furthestVisited = -1;
@@ -193,7 +193,7 @@ namespace DotRecast.Detour
             return result.Count;
         }
 
-        public static int MergeCorridorEndMoved(ref List<long> path, int npath, int maxPath, List<long> visited, int nvisited)
+        public static int MergeCorridorEndMoved(ref List<long> path, int npath, int maxPath, Span<long> visited, int nvisited)
         {
             int furthestPath = -1;
             int furthestVisited = -1;
@@ -226,7 +226,10 @@ namespace DotRecast.Detour
 
             // Concatenate paths.
             List<long> result = path.GetRange(0, furthestPath);
-            result.AddRange(visited.GetRange(furthestVisited, nvisited - furthestVisited));
+            foreach (var v in visited.Slice(furthestVisited, nvisited - furthestVisited))
+            {
+                result.Add(v);
+            }
 
             path = result;
             return result.Count;

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

@@ -37,16 +37,16 @@ namespace DotRecast.Recast.Toolset.Tools
 
             pathIterPolys.Clear();
             pathIterPolyCount = 0;
-            
+
             smoothPath.Clear();
 
             var opt = new DtFindPathOption(enableRaycast ? DtFindPathOptions.DT_FINDPATH_ANY_ANGLE : 0, float.MaxValue);
             navQuery.FindPath(startRef, endRef, startPt, endPt, filter, ref pathIterPolys, opt);
             if (0 >= pathIterPolys.Count)
                 return DtStatus.DT_FAILURE;
-            
+
             pathIterPolyCount = pathIterPolys.Count;
-            
+
             // Iterate over the path to find smooth path on the detail mesh surface.
             navQuery.ClosestPointOnPoly(startRef, startPt, out var iterPos, out var _);
             navQuery.ClosestPointOnPoly(pathIterPolys[pathIterPolys.Count - 1], endPt, out var targetPos, out var _);
@@ -56,8 +56,10 @@ namespace DotRecast.Recast.Toolset.Tools
 
             smoothPath.Clear();
             smoothPath.Add(iterPos);
-            var visited = new List<long>();
+
-            
+            Span<long> visited = stackalloc long[16];
+            int nvisited = 0;
+
 
             // Move towards target a small advancement at a time until target reached or
             // when ran out of memory to store the path.
@@ -69,7 +71,7 @@ namespace DotRecast.Recast.Toolset.Tools
                 {
                     break;
                 }
-                
+
                 bool endOfPath = (steerPosFlag & DtStraightPathFlags.DT_STRAIGHTPATH_END) != 0
                     ? true
                     : false;
@@ -89,15 +91,15 @@ namespace DotRecast.Recast.Toolset.Tools
                 {
                     len = STEP_SIZE / len;
                 }
-                
+
                 RcVec3f moveTgt = RcVecUtils.Mad(iterPos, delta, len);
 
                 // Move
-                navQuery.MoveAlongSurface(pathIterPolys[0], iterPos, moveTgt, filter, out var result, ref visited);
+                navQuery.MoveAlongSurface(pathIterPolys[0], iterPos, moveTgt, filter, out var result, visited, out nvisited, 16);
 
                 iterPos = result;
 
-                pathIterPolyCount = DtPathUtils.MergeCorridorStartMoved(ref pathIterPolys, pathIterPolyCount, MAX_POLYS, visited, visited.Count);
+                pathIterPolyCount = DtPathUtils.MergeCorridorStartMoved(ref pathIterPolys, pathIterPolyCount, MAX_POLYS, visited, nvisited);
                 pathIterPolyCount = DtPathUtils.FixupShortcuts(ref pathIterPolys, pathIterPolyCount, navQuery);
 
                 var status = navQuery.GetPolyHeight(pathIterPolys[0], result, out var h);

test/DotRecast.Detour.Test/MoveAlongSurfaceTest.cs

@@ -16,13 +16,13 @@ freely, subject to the following restrictions:
 3. This notice may not be removed or altered from any source distribution.
 */
 
+using System;
 using System.Collections.Generic;
 using DotRecast.Core.Numerics;
 using NUnit.Framework;
 
 namespace DotRecast.Detour.Test;
 
-
 public class MoveAlongSurfaceTest : AbstractDetourTest
 {
     private static readonly long[][] VISITED =
@@ -69,20 +69,21 @@ public class MoveAlongSurfaceTest : AbstractDetourTest
     public void TestMoveAlongSurface()
     {
         IDtQueryFilter filter = new DtQueryDefaultFilter();
-        var visited = new List<long>();
+        const int MAX_VISITED = 32;
+        Span<long> visited = stackalloc long[MAX_VISITED];
         for (int i = 0; i < startRefs.Length; i++)
         {
             long startRef = startRefs[i];
             RcVec3f startPos = startPoss[i];
             RcVec3f endPos = endPoss[i];
-            var status = query.MoveAlongSurface(startRef, startPos, endPos, filter, out var result, ref visited);
+            var status = query.MoveAlongSurface(startRef, startPos, endPos, filter, out var result, visited, out var nvisited, MAX_VISITED);
             Assert.That(status.Succeeded(), Is.True);
 
             Assert.That(result.X, Is.EqualTo(POSITION[i].X).Within(0.01f));
             Assert.That(result.Y, Is.EqualTo(POSITION[i].Y).Within(0.01f));
             Assert.That(result.Z, Is.EqualTo(POSITION[i].Z).Within(0.01f));
 
-            Assert.That(visited.Count, Is.EqualTo(VISITED[i].Length));
+            Assert.That(nvisited, Is.EqualTo(VISITED[i].Length));
             for (int j = 0; j < 3; j++)
             {
                 Assert.That(visited[j], Is.EqualTo(VISITED[i][j]));