Migrated some small types to structs

src/DotRecast.Detour.Dynamic/DtDynamicTile.cs

@@ -99,7 +99,7 @@ namespace DotRecast.Detour.Dynamic
                 config.maxEdgeLen, config.maxSimplificationError,
                 Math.Min(DtDynamicNavMesh.MAX_VERTS_PER_POLY, config.vertsPerPoly),
                 config.detailSampleDistance, config.detailSampleMaxError,
-                true, true, true, null, true);
+                true, true, true, default, true);
             RcBuilderResult r = builder.Build(vt.tileX, vt.tileZ, null, rcConfig, heightfield, telemetry);
             if (config.keepIntermediateResults)
             {

src/DotRecast.Recast.Toolset/Builder/SampleAreaModifications.cs

@@ -61,7 +61,15 @@ namespace DotRecast.Recast.Toolset.Builder
 
         public static RcAreaModification OfValue(int value)
         {
-            return Values.FirstOrDefault(x => x.Value == value) ?? SAMPLE_AREAMOD_GRASS;
+            foreach(var v in Values)
+            {
+                if(v.Value == value)
+                {
+                    return v;
+                }
+            }
+
+            return SAMPLE_AREAMOD_GRASS;
         }
     }
 }

src/DotRecast.Recast/RcAreaModification.cs

@@ -20,7 +20,7 @@ freely, subject to the following restrictions:
 
 namespace DotRecast.Recast
 {
-    public class RcAreaModification
+    public readonly struct RcAreaModification
     {
         public const int RC_AREA_FLAGS_MASK = 0x3F;
 
@@ -58,12 +58,12 @@ namespace DotRecast.Recast
             Mask = other.Mask;
         }
 
-        public int GetMaskedValue()
+        public readonly int GetMaskedValue()
         {
             return Value & Mask;
         }
 
-        public int Apply(int area)
+        public readonly int Apply(int area)
         {
             return ((Value & Mask) | (area & ~Mask));
         }

src/DotRecast.Recast/RcBuilder.cs

@@ -218,21 +218,11 @@ namespace DotRecast.Recast
                 // Prepare for region partitioning, by calculating distance field
                 // along the walkable surface.
                 RcRegions.BuildDistanceField(ctx, chf);
-                // Partition the walkable surface into simple regions without holes.
-                RcRegions.BuildRegions(ctx, chf, cfg.MinRegionArea, cfg.MergeRegionArea);
-            }
-            else if (cfg.Partition == RcPartitionType.MONOTONE.Value)
-            {
-                // Partition the walkable surface into simple regions without holes.
-                // Monotone partitioning does not need distancefield.
-                RcRegions.BuildRegionsMonotone(ctx, chf, cfg.MinRegionArea, cfg.MergeRegionArea);
-            }
-            else
-            {
-                // Partition the walkable surface into simple regions without holes.
-                RcRegions.BuildLayerRegions(ctx, chf, cfg.MinRegionArea);
             }
 
+            // Partition the walkable surface into simple regions without holes.
+            RcRegions.BuildRegions(ctx, chf, cfg.MinRegionArea, cfg.MergeRegionArea, RcPartitionType.OfValue(cfg.Partition));
+
             //
             // Step 5. Trace and simplify region contours.
             //

src/DotRecast.Recast/RcCommons.cs

@@ -36,7 +36,7 @@ namespace DotRecast.Recast
         /// @param[in]		span			The span to update.
         /// @param[in]		direction		The direction to set. [Limits: 0 <= value < 4]
         /// @param[in]		neighborIndex	The index of the neighbor span.
-        public static void SetCon(RcCompactSpan span, int direction, int neighborIndex)
+        public static void SetCon(ref RcCompactSpan span, int direction, int neighborIndex)
         {
             int shift = direction * 6;
             int con = span.con;

src/DotRecast.Recast/RcCompactSpan.cs

@@ -21,7 +21,7 @@ freely, subject to the following restrictions:
 namespace DotRecast.Recast
 {
     /** Represents a span of unobstructed space within a compact heightfield. */
-    public class RcCompactSpan
+    public struct RcCompactSpan
     {
         /** The lower extent of the span. (Measured from the heightfield's base.) */
         public int y;

src/DotRecast.Recast/RcCompacts.cs

@@ -115,11 +115,11 @@ namespace DotRecast.Recast
                     RcCompactCell c = chf.cells[x + y * w];
                     for (int i = c.index, ni = c.index + c.count; i < ni; ++i)
                     {
-                        RcCompactSpan s = chf.spans[i];
+                        ref RcCompactSpan s = ref chf.spans[i];
 
                         for (int dir = 0; dir < 4; ++dir)
                         {
-                            SetCon(s, dir, RC_NOT_CONNECTED);
+                            SetCon(ref s, dir, RC_NOT_CONNECTED);
                             int nx = x + GetDirOffsetX(dir);
                             int ny = y + GetDirOffsetY(dir);
                             // First check that the neighbour cell is in bounds.
@@ -131,7 +131,7 @@ namespace DotRecast.Recast
                             RcCompactCell nc = chf.cells[nx + ny * w];
                             for (int k = nc.index, nk = nc.index + nc.count; k < nk; ++k)
                             {
-                                RcCompactSpan ns = chf.spans[k];
+                                ref RcCompactSpan ns = ref chf.spans[k];
                                 int bot = Math.Max(s.y, ns.y);
                                 int top = Math.Min(s.y + s.h, ns.y + ns.h);
 
@@ -147,7 +147,7 @@ namespace DotRecast.Recast
                                         continue;
                                     }
 
-                                    SetCon(s, dir, lidx);
+                                    SetCon(ref s, dir, lidx);
                                     break;
                                 }
                             }

src/DotRecast.Recast/RcContours.cs

@@ -632,10 +632,6 @@ namespace DotRecast.Recast
                 maxVerts += region.holes[i].contour.nverts;
 
             RcPotentialDiagonal[] diags = new RcPotentialDiagonal[maxVerts];
-            for (int pd = 0; pd < maxVerts; pd++)
-            {
-                diags[pd] = new RcPotentialDiagonal();
-            }
 
             RcContour outline = region.outline;
 
@@ -664,8 +660,7 @@ namespace DotRecast.Recast
                         {
                             int dx = outline.verts[j * 4 + 0] - hole.verts[corner + 0];
                             int dz = outline.verts[j * 4 + 2] - hole.verts[corner + 2];
-                            diags[ndiags].vert = j;
-                            diags[ndiags].dist = dx * dx + dz * dz;
+                            diags[ndiags] = new RcPotentialDiagonal(j, dx * dx + dz * dz);  
                             ndiags++;
                         }
                     }

src/DotRecast.Recast/RcLayers.cs

@@ -30,10 +30,6 @@ namespace DotRecast.Recast
 
     public static class RcLayers
     {
-        const int RC_MAX_LAYERS = RcConstants.RC_NOT_CONNECTED;
-        const int RC_MAX_NEIS = 16;
-
-
         private static void AddUnique(List<int> a, int v)
         {
             if (!a.Contains(v))
@@ -63,10 +59,6 @@ namespace DotRecast.Recast
             Array.Fill(srcReg, 0xFF);
             int nsweeps = chf.width; // Math.Max(chf.width, chf.height);
             RcSweepSpan[] sweeps = new RcSweepSpan[nsweeps];
-            for (int i = 0; i < sweeps.Length; i++)
-            {
-                sweeps[i] = new RcSweepSpan();
-            }
 
             // Partition walkable area into monotone regions.
             int[] prevCount = new int[256];
@@ -305,7 +297,7 @@ namespace DotRecast.Recast
 
                 int newId = ri.layerId;
 
-                for (;;)
+                while (true)
                 {
                     int oldId = 0xff;
 

src/DotRecast.Recast/RcPotentialDiagonal.cs

@@ -1,8 +1,14 @@
-namespace DotRecast.Recast
+namespace DotRecast.Recast
 {
-    public class RcPotentialDiagonal
+    public readonly struct RcPotentialDiagonal
     {
-        public int dist;
-        public int vert;
+        public readonly int vert;
+        public readonly int dist;
+
+        public RcPotentialDiagonal(int vert, int dist)
+        {
+            this.vert = vert;
+            this.dist = dist;
+        }
     }
 }

src/DotRecast.Recast/RcRegions.cs

@@ -1476,8 +1476,50 @@ namespace DotRecast.Recast
         /// @warning The distance field must be created using #rcBuildDistanceField before attempting to build regions.
         ///
         /// @see rcCompactHeightfield, rcCompactSpan, rcBuildDistanceField, rcBuildRegionsMonotone, rcConfig
-        public static void BuildRegionsMonotone(RcTelemetry ctx, RcCompactHeightfield chf, int minRegionArea,
-            int mergeRegionArea)
+        public static void BuildRegions(RcTelemetry ctx, RcCompactHeightfield chf, int minRegionArea,
+            int mergeRegionArea, RcPartition rcPartitiona)
+        {
+            using var timer = ctx.ScopedTimer(RcTimerLabel.RC_TIMER_BUILD_REGIONS);
+
+            int[] srcReg = new int[chf.spanCount];
+
+            if(rcPartitiona == RcPartition.WATERSHED)
+            {
+                BuildRegionsWatershed(ctx, chf, minRegionArea, mergeRegionArea, srcReg);
+            }
+            else
+            {
+                BuildRegionsMonotoneOrLayered(ctx, chf, minRegionArea, mergeRegionArea, srcReg, rcPartitiona == RcPartition.LAYERS);
+            }
+
+            // Write the result out.
+            for (int i = 0; i < chf.spanCount; ++i)
+            {
+                chf.spans[i].reg = srcReg[i];
+            }
+        }
+
+        /// @par
+        ///
+        /// Non-null regions will consist of connected, non-overlapping walkable spans that form a single contour.
+        /// Contours will form simple polygons.
+        ///
+        /// If multiple regions form an area that is smaller than @p minRegionArea, then all spans will be
+        /// re-assigned to the zero (null) region.
+        ///
+        /// Partitioning can result in smaller than necessary regions. @p mergeRegionArea helps
+        /// reduce unnecessarily small regions.
+        ///
+        /// See the #rcConfig documentation for more information on the configuration parameters.
+        ///
+        /// The region data will be available via the rcCompactHeightfield::maxRegions
+        /// and rcCompactSpan::reg fields.
+        ///
+        /// @warning The distance field must be created using #rcBuildDistanceField before attempting to build regions.
+        ///
+        /// @see rcCompactHeightfield, rcCompactSpan, rcBuildDistanceField, rcBuildRegionsMonotone, rcConfig
+        private static void BuildRegionsMonotoneOrLayered(RcTelemetry ctx, RcCompactHeightfield chf, int minRegionArea,
+            int mergeRegionArea, int[] srcReg, bool isLayered)
         {
             using var timer = ctx.ScopedTimer(RcTimerLabel.RC_TIMER_BUILD_REGIONS);
 
@@ -1486,14 +1528,8 @@ namespace DotRecast.Recast
             int borderSize = chf.borderSize;
             int id = 1;
 
-            int[] srcReg = new int[chf.spanCount];
-
             int nsweeps = Math.Max(chf.width, chf.height);
             RcSweepSpan[] sweeps = new RcSweepSpan[nsweeps];
-            for (int i = 0; i < sweeps.Length; i++)
-            {
-                sweeps[i] = new RcSweepSpan();
-            }
 
             // Mark border regions.
             if (borderSize > 0)
@@ -1622,9 +1658,20 @@ namespace DotRecast.Recast
             }
 
             ctx.StartTimer(RcTimerLabel.RC_TIMER_BUILD_REGIONS_FILTER);
+
             // Merge regions and filter out small regions.
             List<int> overlaps = new List<int>();
-            chf.maxRegions = MergeAndFilterRegions(ctx, minRegionArea, mergeRegionArea, id, chf, srcReg, overlaps);
+
+            if (isLayered)
+            {
+                // Merge monotone regions to layers and remove small regions.
+                chf.maxRegions = MergeAndFilterLayerRegions(ctx, minRegionArea, id, chf, srcReg, overlaps);
+            }
+            else
+            {
+                // Merge regions and filter out small regions.
+                chf.maxRegions = MergeAndFilterRegions(ctx, minRegionArea, mergeRegionArea, id, chf, srcReg, overlaps);
+            }
 
             // Monotone partitioning does not generate overlapping regions.
             ctx.StopTimer(RcTimerLabel.RC_TIMER_BUILD_REGIONS_FILTER);
@@ -1655,11 +1702,8 @@ namespace DotRecast.Recast
         /// @warning The distance field must be created using #rcBuildDistanceField before attempting to build regions.
         ///
         /// @see rcCompactHeightfield, rcCompactSpan, rcBuildDistanceField, rcBuildRegionsMonotone, rcConfig
-        public static void BuildRegions(RcTelemetry ctx, RcCompactHeightfield chf, int minRegionArea,
-            int mergeRegionArea)
+        private static void BuildRegionsWatershed(RcTelemetry ctx, RcCompactHeightfield chf, int minRegionArea, int mergeRegionArea, int[] srcReg)
         {
-            using var timer = ctx.ScopedTimer(RcTimerLabel.RC_TIMER_BUILD_REGIONS);
-
             int w = chf.width;
             int h = chf.height;
             int borderSize = chf.borderSize;
@@ -1676,7 +1720,6 @@ namespace DotRecast.Recast
 
             List<int> stack = new List<int>(1024);
 
-            int[] srcReg = new int[chf.spanCount];
             int[] srcDist = new int[chf.spanCount];
 
             int regionId = 1;
@@ -1770,170 +1813,6 @@ namespace DotRecast.Recast
             }
 
             ctx.StopTimer(RcTimerLabel.RC_TIMER_BUILD_REGIONS_FILTER);
-
-            // Write the result out.
-            for (int i = 0; i < chf.spanCount; ++i)
-            {
-                chf.spans[i].reg = srcReg[i];
-            }
-        }
-
-        public static void BuildLayerRegions(RcTelemetry ctx, RcCompactHeightfield chf, int minRegionArea)
-        {
-            using var timer = ctx.ScopedTimer(RcTimerLabel.RC_TIMER_BUILD_REGIONS);
-
-            int w = chf.width;
-            int h = chf.height;
-            int borderSize = chf.borderSize;
-            int id = 1;
-
-            int[] srcReg = new int[chf.spanCount];
-            int nsweeps = Math.Max(chf.width, chf.height);
-            RcSweepSpan[] sweeps = new RcSweepSpan[nsweeps];
-            for (int i = 0; i < sweeps.Length; i++)
-            {
-                sweeps[i] = new RcSweepSpan();
-            }
-
-            // Mark border regions.
-            if (borderSize > 0)
-            {
-                // Make sure border will not overflow.
-                int bw = Math.Min(w, borderSize);
-                int bh = Math.Min(h, borderSize);
-                // Paint regions
-                PaintRectRegion(0, bw, 0, h, id | RC_BORDER_REG, chf, srcReg);
-                id++;
-                PaintRectRegion(w - bw, w, 0, h, id | RC_BORDER_REG, chf, srcReg);
-                id++;
-                PaintRectRegion(0, w, 0, bh, id | RC_BORDER_REG, chf, srcReg);
-                id++;
-                PaintRectRegion(0, w, h - bh, h, id | RC_BORDER_REG, chf, srcReg);
-                id++;
-            }
-
-            int[] prev = new int[1024];
-
-            // Sweep one line at a time.
-            for (int y = borderSize; y < h - borderSize; ++y)
-            {
-                // Collect spans from this row.
-                if (prev.Length <= id * 2)
-                {
-                    prev = new int[id * 2];
-                }
-                else
-                {
-                    Array.Fill(prev, 0, 0, (id) - (0));
-                }
-
-                int rid = 1;
-
-                for (int x = borderSize; x < w - borderSize; ++x)
-                {
-                    RcCompactCell c = chf.cells[x + y * w];
-
-                    for (int i = c.index, ni = c.index + c.count; i < ni; ++i)
-                    {
-                        RcCompactSpan s = chf.spans[i];
-                        if (chf.areas[i] == RC_NULL_AREA)
-                        {
-                            continue;
-                        }
-
-                        // -x
-                        int previd = 0;
-                        if (GetCon(s, 0) != RC_NOT_CONNECTED)
-                        {
-                            int ax = x + GetDirOffsetX(0);
-                            int ay = y + GetDirOffsetY(0);
-                            int ai = chf.cells[ax + ay * w].index + GetCon(s, 0);
-                            if ((srcReg[ai] & RC_BORDER_REG) == 0 && chf.areas[i] == chf.areas[ai])
-                            {
-                                previd = srcReg[ai];
-                            }
-                        }
-
-                        if (previd == 0)
-                        {
-                            previd = rid++;
-                            sweeps[previd].rid = previd;
-                            sweeps[previd].ns = 0;
-                            sweeps[previd].nei = 0;
-                        }
-
-                        // -y
-                        if (GetCon(s, 3) != RC_NOT_CONNECTED)
-                        {
-                            int ax = x + GetDirOffsetX(3);
-                            int ay = y + GetDirOffsetY(3);
-                            int ai = chf.cells[ax + ay * w].index + GetCon(s, 3);
-                            if (srcReg[ai] != 0 && (srcReg[ai] & RC_BORDER_REG) == 0 && chf.areas[i] == chf.areas[ai])
-                            {
-                                int nr = srcReg[ai];
-                                if (sweeps[previd].nei == 0 || sweeps[previd].nei == nr)
-                                {
-                                    sweeps[previd].nei = nr;
-                                    sweeps[previd].ns++;
-                                    if (prev.Length <= nr)
-                                    {
-                                        Array.Resize(ref prev, prev.Length * 2);
-                                    }
-
-                                    prev[nr]++;
-                                }
-                                else
-                                {
-                                    sweeps[previd].nei = RC_NULL_NEI;
-                                }
-                            }
-                        }
-
-                        srcReg[i] = previd;
-                    }
-                }
-
-                // Create unique ID.
-                for (int i = 1; i < rid; ++i)
-                {
-                    if (sweeps[i].nei != RC_NULL_NEI && sweeps[i].nei != 0 && prev[sweeps[i].nei] == sweeps[i].ns)
-                    {
-                        sweeps[i].id = sweeps[i].nei;
-                    }
-                    else
-                    {
-                        sweeps[i].id = id++;
-                    }
-                }
-
-                // Remap IDs
-                for (int x = borderSize; x < w - borderSize; ++x)
-                {
-                    RcCompactCell c = chf.cells[x + y * w];
-
-                    for (int i = c.index, ni = c.index + c.count; i < ni; ++i)
-                    {
-                        if (srcReg[i] > 0 && srcReg[i] < rid)
-                        {
-                            srcReg[i] = sweeps[srcReg[i]].id;
-                        }
-                    }
-                }
-            }
-
-            ctx.StartTimer(RcTimerLabel.RC_TIMER_BUILD_REGIONS_FILTER);
-
-            // Merge monotone regions to layers and remove small regions.
-            List<int> overlaps = new List<int>();
-            chf.maxRegions = MergeAndFilterLayerRegions(ctx, minRegionArea, id, chf, srcReg, overlaps);
-
-            ctx.StopTimer(RcTimerLabel.RC_TIMER_BUILD_REGIONS_FILTER);
-
-            // Store the result out.
-            for (int i = 0; i < chf.spanCount; ++i)
-            {
-                chf.spans[i].reg = srcReg[i];
-            }
         }
     }
 }

src/DotRecast.Recast/RcSweepSpan.cs

@@ -1,6 +1,6 @@
-namespace DotRecast.Recast
+namespace DotRecast.Recast
 {
-    public class RcSweepSpan
+    public struct RcSweepSpan
     {
         public int rid; // row id
         public int id; // region id

test/DotRecast.Recast.Test/RecastSoloMeshTest.cs

@@ -217,21 +217,11 @@ public class RecastSoloMeshTest
             // Prepare for region partitioning, by calculating distance field
             // along the walkable surface.
             RcRegions.BuildDistanceField(m_ctx, m_chf);
-            // Partition the walkable surface into simple regions without holes.
-            RcRegions.BuildRegions(m_ctx, m_chf, cfg.MinRegionArea, cfg.MergeRegionArea);
-        }
-        else if (m_partitionType == RcPartition.MONOTONE)
-        {
-            // Partition the walkable surface into simple regions without holes.
-            // Monotone partitioning does not need distancefield.
-            RcRegions.BuildRegionsMonotone(m_ctx, m_chf, cfg.MinRegionArea, cfg.MergeRegionArea);
-        }
-        else
-        {
-            // Partition the walkable surface into simple regions without holes.
-            RcRegions.BuildLayerRegions(m_ctx, m_chf, cfg.MinRegionArea);
         }
 
+        // Partition the walkable surface into simple regions without holes.
+        RcRegions.BuildRegions(m_ctx, m_chf, cfg.MinRegionArea, cfg.MergeRegionArea, RcPartitionType.OfValue(cfg.Partition));
+
         Assert.That(m_chf.maxDistance, Is.EqualTo(expDistance), "maxDistance");
         Assert.That(m_chf.maxRegions, Is.EqualTo(expRegions), "Regions");
         //