Changed new RcVec3f[3] to stackalloc RcVec3f[3] in DtNavMesh.GetPolyH…

…eight() to reduce heap allocation.

CHANGELOG.md

@@ -14,6 +14,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ### Changed
 - Changed data structure of 'neis' from List<byte> to byte[] for optimized memory usage and improved access speed in `DtLayerMonotoneRegion`
+- Changed new RcVec3f[3] to stackalloc RcVec3f[3] in DtNavMesh.GetPolyHeight() to reduce heap allocation
 
 ### Removed
 - Nothing

src/DotRecast.Detour/DtNavMesh.cs

@@ -66,7 +66,7 @@ public DtStatus Init(DtNavMeshParams param, int maxVertsPerPoly)
             m_tiles = new DtMeshTile[m_maxTiles];
             m_posLookup = new DtMeshTile[m_tileLutSize];
             m_nextFree = null;
-            for (int i = m_maxTiles-1; i >= 0; --i)
+            for (int i = m_maxTiles - 1; i >= 0; --i)
             {
                 m_tiles[i] = new DtMeshTile(i);
                 m_tiles[i].salt = 1;
@@ -1045,6 +1045,7 @@ RcVec3f ClosestPointOnDetailEdges(DtMeshTile tile, DtPoly poly, RcVec3f pos, boo
             RcVec3f pmin = new RcVec3f();
             RcVec3f pmax = new RcVec3f();
 
+            Span<RcVec3f> tempV = stackalloc RcVec3f[3];
             if (tile.data.detailMeshes != null)
             {
                 ref DtPolyDetail pd = ref tile.data.detailMeshes[ip];
@@ -1057,7 +1058,7 @@ RcVec3f ClosestPointOnDetailEdges(DtMeshTile tile, DtPoly poly, RcVec3f pos, boo
                         continue;
                     }
 
-                    RcVec3f[] v = new RcVec3f[3];
+                    Span<RcVec3f> v = tempV;
                     for (int j = 0; j < 3; ++j)
                     {
                         if (tris[ti + j] < poly.vertCount)
@@ -1105,7 +1106,7 @@ RcVec3f ClosestPointOnDetailEdges(DtMeshTile tile, DtPoly poly, RcVec3f pos, boo
             }
             else
             {
-                RcVec3f[] v = new RcVec3f[2];
+                Span<RcVec3f> v = tempV.Slice(0, 2);
                 for (int j = 0; j < poly.vertCount; ++j)
                 {
                     int k = (j + 1) % poly.vertCount;
@@ -1156,13 +1157,14 @@ public bool GetPolyHeight(DtMeshTile tile, DtPoly poly, RcVec3f pos, out float h
             }
 
             // Find height at the location.
+            Span<RcVec3f> tempV = stackalloc RcVec3f[3];
             if (tile.data.detailMeshes != null)
             {
                 ref DtPolyDetail pd = ref tile.data.detailMeshes[ip];
                 for (int j = 0; j < pd.triCount; ++j)
                 {
                     int t = (pd.triBase + j) * 4;
-                    RcVec3f[] v = new RcVec3f[3];
+                    Span<RcVec3f> v = tempV;
                     for (int k = 0; k < 3; ++k)
                     {
                         if (tile.data.detailTris[t + k] < poly.vertCount)
@@ -1196,7 +1198,7 @@ public bool GetPolyHeight(DtMeshTile tile, DtPoly poly, RcVec3f pos, out float h
             }
             else
             {
-                RcVec3f[] v = new RcVec3f[3];
+                Span<RcVec3f> v = tempV;
                 v[0].X = tile.data.verts[poly.verts[0] * 3];
                 v[0].Y = tile.data.verts[poly.verts[0] * 3 + 1];
                 v[0].Z = tile.data.verts[poly.verts[0] * 3 + 2];

src/DotRecast.Detour/DtNavMeshRaycast.cs

@@ -17,6 +17,7 @@ misrepresented as being the original software.
 3. This notice may not be removed or altered from any source distribution.
 */
 
+using System;
 using DotRecast.Core;
 using DotRecast.Core.Numerics;
 
@@ -48,6 +49,7 @@ public static bool Raycast(DtNavMesh mesh, RcVec3f src, RcVec3f dst, out float h
         private static bool Raycast(DtMeshTile tile, RcVec3f sp, RcVec3f sq, out float hitTime)
         {
             hitTime = 0.0f;
+            Span<RcVec3f> tempVerts = stackalloc RcVec3f[3];
             for (int i = 0; i < tile.data.header.polyCount; ++i)
             {
                 DtPoly p = tile.data.polys[i];
@@ -58,7 +60,7 @@ private static bool Raycast(DtMeshTile tile, RcVec3f sp, RcVec3f sq, out float h
 
                 ref DtPolyDetail pd = ref tile.data.detailMeshes[i];
 
-                RcVec3f[] verts = new RcVec3f[3];
+                Span<RcVec3f> verts = tempVerts;
                 for (int j = 0; j < pd.triCount; ++j)
                 {
                     int t = (pd.triBase + j) * 4;

src/DotRecast.Recast.Toolset/Gizmos/RcCapsuleGizmo.cs

@@ -19,7 +19,7 @@ public RcCapsuleGizmo(RcVec3f start, RcVec3f end, float radius)
                 0.5f * (start.Z + end.Z)
             };
             RcVec3f axis = new RcVec3f(end.X - start.X, end.Y - start.Y, end.Z - start.Z);
-            RcVec3f[] normals = new RcVec3f[3];
+            Span<RcVec3f> normals = stackalloc RcVec3f[3];
             normals[1] = new RcVec3f(end.X - start.X, end.Y - start.Y, end.Z - start.Z);
             normals[1] = RcVec3f.Normalize(normals[1]);
             normals[0] = GetSideVector(axis);

src/DotRecast.Recast.Toolset/Gizmos/RcCylinderGizmo.cs

@@ -19,7 +19,7 @@ public RcCylinderGizmo(RcVec3f start, RcVec3f end, float radius)
                 0.5f * (start.Z + end.Z)
             );
             RcVec3f axis = new RcVec3f(end.X - start.X, end.Y - start.Y, end.Z - start.Z);
-            RcVec3f[] normals = new RcVec3f[3];
+            Span<RcVec3f> normals = stackalloc RcVec3f[3];
             normals[1] = new RcVec3f(end.X - start.X, end.Y - start.Y, end.Z - start.Z);
             normals[1] = RcVec3f.Normalize(normals[1]);
             normals[0] = GetSideVector(axis);

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

@@ -380,7 +380,7 @@ public DtStatus FindPolysAroundShape(DtNavMeshQuery navQuery, float agentHeight,
             float nx = (epos.Z - spos.Z) * 0.25f;
             float nz = -(epos.X - spos.X) * 0.25f;
 
-            var tempQueryPoly = new RcVec3f[4];
+            RcVec3f[] tempQueryPoly = new RcVec3f[4];
             tempQueryPoly[0].X = spos.X + nx * 1.2f;
             tempQueryPoly[0].Y = spos.Y + agentHeight / 2;
             tempQueryPoly[0].Z = spos.Z + nz * 1.2f;

src/DotRecast.Recast/RcPolyMeshRaycast.cs

@@ -17,6 +17,7 @@ misrepresented as being the original software.
 3. This notice may not be removed or altered from any source distribution.
 */
 
+using System;
 using System.Collections.Generic;
 using DotRecast.Core;
 using DotRecast.Core.Numerics;
@@ -45,6 +46,7 @@ public static bool Raycast(IList<RcBuilderResult> results, RcVec3f src, RcVec3f
         private static bool Raycast(RcPolyMesh poly, RcPolyMeshDetail meshDetail, RcVec3f sp, RcVec3f sq, out float hitTime)
         {
             hitTime = 0;
+            Span<RcVec3f> tempVs = stackalloc RcVec3f[3];
             if (meshDetail != null)
             {
                 for (int i = 0; i < meshDetail.nmeshes; ++i)
@@ -57,7 +59,7 @@ private static bool Raycast(RcPolyMesh poly, RcPolyMeshDetail meshDetail, RcVec3
                     int tris = btris * 4;
                     for (int j = 0; j < ntris; ++j)
                     {
-                        RcVec3f[] vs = new RcVec3f[3];
+                        Span<RcVec3f> vs = tempVs;
                         for (int k = 0; k < 3; ++k)
                         {
                             vs[k].X = meshDetail.verts[verts + meshDetail.tris[tris + j * 4 + k] * 3];