Handle different slopes in mmaps (#24765)

* Tools/MMAPs: Remove input argument --maxAngle

Remove input argument --maxAngle . This should be just hardcoded in MapBuilder::GetMapSpecificConfig() so all settings are easily found in the same place instead of being spread around.

* Tools/MMAPs: Add new area type NAV_AREA_GROUND_STEEP

Add new area type NAV_AREA_GROUND_STEEP for ground with slope in the range (55, 70] .
NAV_AREA_GROUND is used for ground with range [0, 55] .
NAV_AREA_GROUND_STEEP takes priority over NAV_AREA_GROUND.

* Tools/MMAPs: Fix NAV_GROUND_STEEP flag not being saved in the mmtile

* Core/PathFinding: Implement NAV_GROUND_STEEP flag

Implement NAV_GROUND_STEEP flag, used only by Creatures that are in combat or evading.

* Distinguish between RC_WALKABLE_AREA and NAV_AREA_GROUND.

* Allow mobs in combat to walk on steeps up to 80°

* Allow mobs in combat to walk on steeps up to 85°.
Disable rcFilterLedgeSpans() filter as it removed long steep spans.

* Increase cost of steep spans to try making creatures walk around obstacles instead of walking on them

* Revert last commit

(cherry picked from commit 995a443da219ec773febd7dd29d18f3cefaa1f3b)

7 files changed, 46 insertions, 38 deletions

diff --git a/dep/recastnavigation/Recast/Include/Recast.h b/dep/recastnavigation/Recast/Include/Recast.h
index fa25a98bd2a..19c26e20c4a 100644
--- a/dep/recastnavigation/Recast/Include/Recast.h
+++ b/dep/recastnavigation/Recast/Include/Recast.h
@@ -224,6 +224,9 @@ struct rcConfig
 	/// The maximum slope that is considered walkable. [Limits: 0 <= value < 90] [Units: Degrees] 
 	float walkableSlopeAngle;
 
+	/// The maximum slope that is considered walkable but not steep. It should be lower/equal than walkableSlopeAngle. [Limits: 0 <= value < 90] [Units: Degrees] 
+	float walkableSlopeAngleNotSteep;
+
 	/// Minimum floor to 'ceiling' height that will still allow the floor area to 
 	/// be considered walkable. [Limit: >= 3] [Units: vx] 
 	int walkableHeight;
@@ -810,7 +813,7 @@ bool rcCreateHeightfield(rcContext* ctx, rcHeightfield& hf, int width, int heigh
 ///  @param[in]		nt					The number of triangles.
 ///  @param[out]	areas				The triangle area ids. [Length: >= @p nt]
 void rcMarkWalkableTriangles(rcContext* ctx, const float walkableSlopeAngle, const float* verts, int nv,
-							 const int* tris, int nt, unsigned char* areas); 
+							 const int* tris, int nt, unsigned char* areas, unsigned char areaType = RC_WALKABLE_AREA);
 
 /// Sets the area id of all triangles with a slope greater than or equal to the specified value to #RC_NULL_AREA.
 ///  @ingroup recast
diff --git a/dep/recastnavigation/Recast/Source/Recast.cpp b/dep/recastnavigation/Recast/Source/Recast.cpp
index 1b71710cdc8..a33ca5cf2fc 100644
--- a/dep/recastnavigation/Recast/Source/Recast.cpp
+++ b/dep/recastnavigation/Recast/Source/Recast.cpp
@@ -334,7 +334,7 @@ static void calcTriNormal(const float* v0, const float* v1, const float* v2, flo
 void rcMarkWalkableTriangles(rcContext* ctx, const float walkableSlopeAngle,
 							 const float* verts, int nv,
 							 const int* tris, int nt,
-							 unsigned char* areas)
+							 unsigned char* areas, unsigned char areaType)
 {
 	rcIgnoreUnused(ctx);
 	rcIgnoreUnused(nv);
@@ -349,7 +349,7 @@ void rcMarkWalkableTriangles(rcContext* ctx, const float walkableSlopeAngle,
 		calcTriNormal(&verts[tri[0]*3], &verts[tri[1]*3], &verts[tri[2]*3], norm);
 		// Check if the face is walkable.
 		if (norm[1] > walkableThr)
-			areas[i] = RC_WALKABLE_AREA;
+			areas[i] = areaType;
 	}
 }
 
diff --git a/src/common/Collision/Maps/MMapDefines.h b/src/common/Collision/Maps/MMapDefines.h
index e12c8cac49e..6298775ba6f 100644
--- a/src/common/Collision/Maps/MMapDefines.h
+++ b/src/common/Collision/Maps/MMapDefines.h
@@ -51,17 +51,22 @@ enum NavArea
     NAV_AREA_EMPTY          = 0,
     // areas 1-60 will be used for destructible areas (currently skipped in vmaps, WMO with flag 1)
     // ground is the highest value to make recast choose ground over water when merging surfaces very close to each other (shallow water would be walkable)
-    NAV_AREA_GROUND         = 63,
-    NAV_AREA_WATER          = 62,
-    NAV_AREA_MAGMA_SLIME    = 61 // don't need to differentiate between them
+    NAV_AREA_GROUND_STEEP   = 11,
+    NAV_AREA_GROUND         = 10,
+    NAV_AREA_WATER          = 9,
+    NAV_AREA_MAGMA_SLIME    = 8, // don't need to differentiate between them
+    NAV_AREA_MAX_VALUE      = NAV_AREA_GROUND_STEEP,
+    NAV_AREA_MIN_VALUE      = NAV_AREA_MAGMA_SLIME,
+    NAV_AREA_ALL_MASK       = 0x3F // max allowed value
 };
 
 enum NavTerrainFlag
 {
-    NAV_EMPTY       = 0x00,
-    NAV_GROUND      = 1 << (63 - NAV_AREA_GROUND),
-    NAV_WATER       = 1 << (63 - NAV_AREA_WATER),
-    NAV_MAGMA_SLIME = 1 << (63 - NAV_AREA_MAGMA_SLIME)
+    NAV_EMPTY        = 0x00,
+    NAV_GROUND_STEEP = 1 << (NAV_AREA_MAX_VALUE - NAV_AREA_GROUND_STEEP),
+    NAV_GROUND       = 1 << (NAV_AREA_MAX_VALUE - NAV_AREA_GROUND),
+    NAV_WATER        = 1 << (NAV_AREA_MAX_VALUE - NAV_AREA_WATER),
+    NAV_MAGMA_SLIME  = 1 << (NAV_AREA_MAX_VALUE - NAV_AREA_MAGMA_SLIME)
 };
 
 #endif // MMapDefines_h__
diff --git a/src/server/game/Movement/PathGenerator.cpp b/src/server/game/Movement/PathGenerator.cpp
index 0effe2a5d87..a4b15baadb3 100644
--- a/src/server/game/Movement/PathGenerator.cpp
+++ b/src/server/game/Movement/PathGenerator.cpp
@@ -679,6 +679,7 @@ void PathGenerator::UpdateFilter()
     // allow creatures to cheat and use different movement types if they are moved
     // forcefully into terrain they can't normally move in
     if (Unit const* _sourceUnit = _source->ToUnit())
+    {
         if (_sourceUnit->IsInWater() || _sourceUnit->IsUnderWater())
         {
             uint16 includedFlags = _filter.getIncludeFlags();
@@ -688,6 +689,11 @@ void PathGenerator::UpdateFilter()
 
             _filter.setIncludeFlags(includedFlags);
         }
+
+        if (Creature const* _sourceCreature = _source->ToCreature())
+            if (_sourceCreature->IsInCombat() || _sourceCreature->IsInEvadeMode())
+                _filter.setIncludeFlags(_filter.getIncludeFlags() | NAV_GROUND_STEEP);
+    }
 }
 
 NavTerrainFlag PathGenerator::GetNavTerrain(float x, float y, float z)
diff --git a/src/tools/mmaps_generator/MapBuilder.cpp b/src/tools/mmaps_generator/MapBuilder.cpp
index 6e3adc79a04..1b83daf1c1c 100644
--- a/src/tools/mmaps_generator/MapBuilder.cpp
+++ b/src/tools/mmaps_generator/MapBuilder.cpp
@@ -31,7 +31,7 @@
 
 namespace MMAP
 {
-    MapBuilder::MapBuilder(float maxWalkableAngle, bool skipLiquid,
+    MapBuilder::MapBuilder(bool skipLiquid,
         bool skipContinents, bool skipJunkMaps, bool skipBattlegrounds,
         bool debugOutput, bool bigBaseUnit, int mapid, char const* offMeshFilePath) :
         m_terrainBuilder     (nullptr),
@@ -40,7 +40,6 @@ namespace MMAP
         m_skipContinents     (skipContinents),
         m_skipJunkMaps       (skipJunkMaps),
         m_skipBattlegrounds  (skipBattlegrounds),
-        m_maxWalkableAngle   (maxWalkableAngle),
         m_bigBaseUnit        (bigBaseUnit),
         m_mapid              (mapid),
         m_totalTiles         (0u),
@@ -588,16 +587,26 @@ namespace MMAP
                 }
 
                 // mark all walkable tiles, both liquids and solids
+
+                /* we want to have triangles with slope less than walkableSlopeAngleNotSteep (<= 55) to have NAV_AREA_GROUND
+                 * and with slope between walkableSlopeAngleNotSteep and walkableSlopeAngle (55 < .. <= 70) to have NAV_AREA_GROUND_STEEP.
+                 * we achieve this using recast API: memset everything to NAV_AREA_GROUND_STEEP, call rcClearUnwalkableTriangles with 70 so
+                 * any area above that will get RC_NULL_AREA (unwalkable), then call rcMarkWalkableTriangles with 55 to set NAV_AREA_GROUND
+                 * on anything below 55 . Players and idle Creatures can use NAV_AREA_GROUND, while Creatures in combat can use NAV_AREA_GROUND_STEEP.
+                 */
                 unsigned char* triFlags = new unsigned char[tTriCount];
-                memset(triFlags, NAV_AREA_GROUND, tTriCount*sizeof(unsigned char));
+                memset(triFlags, NAV_AREA_GROUND_STEEP, tTriCount*sizeof(unsigned char));
                 rcClearUnwalkableTriangles(m_rcContext, tileCfg.walkableSlopeAngle, tVerts, tVertCount, tTris, tTriCount, triFlags);
+                rcMarkWalkableTriangles(m_rcContext, tileCfg.walkableSlopeAngleNotSteep, tVerts, tVertCount, tTris, tTriCount, triFlags, NAV_AREA_GROUND);
                 rcRasterizeTriangles(m_rcContext, tVerts, tVertCount, tTris, triFlags, tTriCount, *tile.solid, config.walkableClimb);
                 delete[] triFlags;
 
                 rcFilterLowHangingWalkableObstacles(m_rcContext, config.walkableClimb, *tile.solid);
-                rcFilterLedgeSpans(m_rcContext, tileCfg.walkableHeight, tileCfg.walkableClimb, *tile.solid);
+                // disabled as it ignores walkableSlopeAngle settings
+                //rcFilterLedgeSpans(m_rcContext, tileCfg.walkableHeight, tileCfg.walkableClimb, *tile.solid);
                 rcFilterWalkableLowHeightSpans(m_rcContext, tileCfg.walkableHeight, *tile.solid);
 
+                // add liquid triangles
                 rcRasterizeTriangles(m_rcContext, lVerts, lVertCount, lTris, lTriFlags, lTriCount, *tile.solid, config.walkableClimb);
 
                 // compact heightfield spans
@@ -702,10 +711,10 @@ namespace MMAP
         // TODO: special flags for DYNAMIC polygons, ie surfaces that can be turned on and off
         for (int i = 0; i < iv.polyMesh->npolys; ++i)
         {
-            if (uint8 area = iv.polyMesh->areas[i] & RC_WALKABLE_AREA)
+            if (uint8 area = iv.polyMesh->areas[i] & NAV_AREA_ALL_MASK)
             {
-                if (area >= NAV_AREA_MAGMA_SLIME)
-                    iv.polyMesh->flags[i] = 1 << (63 - area);
+                if (area >= NAV_AREA_MIN_VALUE)
+                    iv.polyMesh->flags[i] = 1 << (NAV_AREA_MAX_VALUE - area);
                 else
                     iv.polyMesh->flags[i] = NAV_GROUND; // TODO: these will be dynamic in future
             }
@@ -978,7 +987,8 @@ namespace MMAP
         config.maxVertsPerPoly = DT_VERTS_PER_POLYGON;
         config.cs = tileConfig.BASE_UNIT_DIM;
         config.ch = tileConfig.BASE_UNIT_DIM;
-        config.walkableSlopeAngle = m_maxWalkableAngle;
+        config.walkableSlopeAngle = 85;
+        config.walkableSlopeAngleNotSteep = 55;
         config.tileSize = tileConfig.VERTEX_PER_TILE;
         config.walkableRadius = m_bigBaseUnit ? 1 : 2;
         config.borderSize = config.walkableRadius + 3;
diff --git a/src/tools/mmaps_generator/MapBuilder.h b/src/tools/mmaps_generator/MapBuilder.h
index f2fd5d296d7..312d3c07786 100644
--- a/src/tools/mmaps_generator/MapBuilder.h
+++ b/src/tools/mmaps_generator/MapBuilder.h
@@ -96,8 +96,7 @@ namespace MMAP
     class MapBuilder
     {
         public:
-            MapBuilder(float maxWalkableAngle   = 70.f,
-                bool skipLiquid          = false,
+            MapBuilder(bool skipLiquid   = false,
                 bool skipContinents      = false,
                 bool skipJunkMaps        = true,
                 bool skipBattlegrounds   = false,
@@ -164,7 +163,6 @@ namespace MMAP
             bool m_skipJunkMaps;
             bool m_skipBattlegrounds;
 
-            float m_maxWalkableAngle;
             bool m_bigBaseUnit;
 
             int32 m_mapid;
diff --git a/src/tools/mmaps_generator/PathGenerator.cpp b/src/tools/mmaps_generator/PathGenerator.cpp
index 9625b1d7f1f..2e9f3913edf 100644
--- a/src/tools/mmaps_generator/PathGenerator.cpp
+++ b/src/tools/mmaps_generator/PathGenerator.cpp
@@ -99,7 +99,6 @@ bool handleArgs(int argc, char** argv,
                int &mapnum,
                int &tileX,
                int &tileY,
-               float &maxAngle,
                bool &skipLiquid,
                bool &skipContinents,
                bool &skipJunkMaps,
@@ -114,19 +113,7 @@ bool handleArgs(int argc, char** argv,
     char* param = nullptr;
     for (int i = 1; i < argc; ++i)
     {
-        if (strcmp(argv[i], "--maxAngle") == 0)
-        {
-            param = argv[++i];
-            if (!param)
-                return false;
-
-            float maxangle = atof(param);
-            if (maxangle <= 90.f && maxangle >= 45.f)
-                maxAngle = maxangle;
-            else
-                printf("invalid option for '--maxAngle', using default\n");
-        }
-        else if (strcmp(argv[i], "--threads") == 0)
+        if (strcmp(argv[i], "--threads") == 0)
         {
             param = argv[++i];
             if (!param)
@@ -353,7 +340,6 @@ int main(int argc, char** argv)
 
     unsigned int threads = std::thread::hardware_concurrency();
     int mapnum = -1;
-    float maxAngle = 70.0f;
     int tileX = -1, tileY = -1;
     bool skipLiquid = false,
          skipContinents = false,
@@ -366,7 +352,7 @@ int main(int argc, char** argv)
     char* file = nullptr;
 
     bool validParam = handleArgs(argc, argv, mapnum,
-                                 tileX, tileY, maxAngle,
+                                 tileX, tileY,
                                  skipLiquid, skipContinents, skipJunkMaps, skipBattlegrounds,
                                  debugOutput, silent, bigBaseUnit, offMeshInputPath, file, threads);
 
@@ -400,7 +386,7 @@ int main(int argc, char** argv)
         return itr != _liquidTypes.end() ? (1 << itr->second) : 0;
     };
 
-    MapBuilder builder(maxAngle, skipLiquid, skipContinents, skipJunkMaps,
+    MapBuilder builder(skipLiquid, skipContinents, skipJunkMaps,
                        skipBattlegrounds, debugOutput, bigBaseUnit, mapnum, offMeshInputPath);
 
     uint32 start = getMSTime();