Core/Movement: Fix some undermap issues with random movement/fear/blink

Port From (https://github.com/TrinityCore/TrinityCore/commit/4fcc4a330044e84baa1f58ff13e1b4ea7775eb66)

Source/Game/Entities/Object/WorldObject.cs

@@ -3042,10 +3042,19 @@ namespace Game.Entities
         }
 
         public void UpdateAllowedPositionZ(float x, float y, ref float z)
+        {
+            float unused = 0f;
+            UpdateAllowedPositionZ(x, y, ref z, ref unused);
+        }
+
+        public void UpdateAllowedPositionZ(float x, float y, ref float z, ref float groundZ)
         {
             // TODO: Allow transports to be part of dynamic vmap tree
             if (GetTransport())
+            {
+                groundZ = z;
                 return;
+            }
 
             Unit unit = ToUnit();
             if (unit != null)
@@ -3053,31 +3062,35 @@ namespace Game.Entities
                 if (!unit.CanFly())
                 {
                     bool canSwim = unit.CanSwim();
-                    float groundZ = z;
+                    float ground_z = z;
                     float max_z;
                     if (canSwim)
-                        max_z = GetMapWaterOrGroundLevel(x, y, z, ref groundZ);
+                        max_z = GetMapWaterOrGroundLevel(x, y, z, ref ground_z);
                     else
-                        max_z = groundZ = GetMapHeight(x, y, z);
+                        max_z = ground_z = GetMapHeight(x, y, z);
 
                     if (max_z > MapConst.InvalidHeight)
                     {
                         // hovering units cannot go below their hover height
                         float hoverOffset = unit.GetHoverOffset();
                         max_z += hoverOffset;
-                        groundZ += hoverOffset;
+                        ground_z += hoverOffset;
 
                         if (z > max_z)
                             z = max_z;
-                        else if (z < groundZ)
+                        else if (z < ground_z)
-                            z = groundZ;
+                            z = ground_z;
                     }
+
+                    groundZ = ground_z;
                 }
                 else
                 {
                     float ground_z = GetMapHeight(x, y, z) + unit.GetHoverOffset();
                     if (z < ground_z)
                         z = ground_z;
+
+                    groundZ = ground_z;
                 }
             }
             else
@@ -3085,6 +3098,8 @@ namespace Game.Entities
                 float ground_z = GetMapHeight(x, y, z);
                 if (ground_z > MapConst.InvalidHeight)
                     z = ground_z;
+
+                groundZ = ground_z;
             }
         }
 
@@ -3295,10 +3310,28 @@ namespace Game.Entities
                 }
             }
 
+            float groundZ = MapConst.VMAPInvalidHeightValue;
             GridDefines.NormalizeMapCoord(ref pos.posX);
             GridDefines.NormalizeMapCoord(ref pos.posY);
-            UpdateAllowedPositionZ(destx, desty, ref pos.posZ);
+            UpdateAllowedPositionZ(destx, desty, ref pos.posZ, ref groundZ);
             pos.SetOrientation(GetOrientation());
+
+            // position has no ground under it (or is too far away)
+            if (groundZ <= MapConst.InvalidHeight)
+            {
+                Unit unit = ToUnit();
+                if (unit != null)
+                {
+                    // unit can fly, ignore.
+                    if (unit.CanFly())
+                        return;
+
+                    // fall back to gridHeight if any
+                    float gridHeight = GetMap().GetGridHeight(GetPhaseShift(), pos.posX, pos.posY);
+                    if (gridHeight > MapConst.InvalidHeight)
+                        pos.posZ = gridHeight + unit.GetHoverOffset();
+                }
+            }
         }
 
         public float GetFloorZ()

Source/Game/Maps/Map.cs

@@ -1719,13 +1719,9 @@ namespace Game.Maps
             // find raw .map surface under Z coordinates
             float mapHeight = MapConst.VMAPInvalidHeightValue;
             uint terrainMapId = PhasingHandler.GetTerrainMapId(phaseShift, this, x, y);
-            GridMap gmap = GetGridMap(terrainMapId, x, y);
+            float gridHeight = GetGridHeight(phaseShift, x, y);
-            if (gmap != null)
+            if (MathFunctions.fuzzyGe(z, gridHeight - MapConst.GroundHeightTolerance))
-            {
+                mapHeight = gridHeight;
-                float gridHeight = gmap.GetHeight(x, y);
-                if (MathFunctions.fuzzyGe(z, gridHeight - MapConst.GroundHeightTolerance))
-                    mapHeight = gridHeight;
-            }
 
             float vmapHeight = MapConst.VMAPInvalidHeightValue;
             if (checkVMap)
@@ -1746,8 +1742,10 @@ namespace Game.Maps
                     // or if the distance of the vmap height is less the land height distance
                     if (vmapHeight > mapHeight || Math.Abs(mapHeight - z) > Math.Abs(vmapHeight - z))
                         return vmapHeight;
+
                     return mapHeight; // better use .map surface height
                 }
+
                 return vmapHeight; // we have only vmapHeight (if have)
             }
 
@@ -1764,6 +1762,15 @@ namespace Game.Maps
             return GetHeight(phaseShift, pos.GetPositionX(), pos.GetPositionY(), pos.GetPositionZ(), vmap, maxSearchDist);
         }
 
+        public float GetGridHeight(PhaseShift phaseShift, float x, float y)
+        {
+            GridMap gmap = GetGridMap(PhasingHandler.GetTerrainMapId(phaseShift, this, x, y), x, y);
+            if (gmap != null)
+                return gmap.GetHeight(x, y);
+
+            return MapConst.VMAPInvalidHeightValue;
+        }
+        
         public float GetMinHeight(PhaseShift phaseShift, float x, float y)
         {
             GridMap grid = GetGridMap(PhasingHandler.GetTerrainMapId(phaseShift, this, x, y), x, y);

Source/Game/Movement/Generators/ConfusedGenerator.cs

@@ -90,7 +90,7 @@ namespace Game.Movement
                 }
 
                 bool result = _path.CalculatePath(destination.GetPositionX(), destination.GetPositionY(), destination.GetPositionZ());
-                if (!result || _path.GetPathType().HasAnyFlag(PathType.NoPath))
+                if (!result || _path.GetPathType().HasAnyFlag(PathType.NoPath) || _path.GetPathType().HasAnyFlag(PathType.Shortcut))
                 {
                     _timer.Reset(100);
                     return true;

Source/Game/Movement/Generators/FleeingGenerator.cs

@@ -140,7 +140,7 @@ namespace Game.Movement
             }
 
             bool result = _path.CalculatePath(destination.GetPositionX(), destination.GetPositionY(), destination.GetPositionZ());
-            if (!result || _path.GetPathType().HasAnyFlag(PathType.NoPath))
+            if (!result || _path.GetPathType().HasAnyFlag(PathType.NoPath) || _path.GetPathType().HasAnyFlag(PathType.Shortcut))
             {
                 _timer.Reset(100);
                 return;

Source/Game/Movement/Generators/PathGenerator.cs

@@ -529,14 +529,14 @@ namespace Game.Movement
                 // @todo check the exact cases
                 Log.outDebug(LogFilter.Maps, "++ PathGenerator.BuildPointPath FAILED! path sized {0} returned\n", pointCount);
                 BuildShortcut();
-                pathType = PathType.NoPath;
+                pathType |= PathType.NoPath;
                 return;
             }
             else if (pointCount == _pointPathLimit)
             {
                 Log.outDebug(LogFilter.Maps, "++ PathGenerator.BuildPointPath FAILED! path sized {0} returned, lower than limit set to {1}\n", pointCount, _pointPathLimit);
                 BuildShortcut();
-                pathType = PathType.Short;
+                pathType |= PathType.Short;
                 return;
             }
 

Source/Game/Movement/Generators/RandomMovement.cs

@@ -130,7 +130,7 @@ namespace Game.Movement
             }
 
             bool result = _path.CalculatePath(position.GetPositionX(), position.GetPositionY(), position.GetPositionZ());
-            if (!result || _path.GetPathType().HasAnyFlag(PathType.NoPath))
+            if (!result || _path.GetPathType().HasAnyFlag(PathType.NoPath) || _path.GetPathType().HasAnyFlag(PathType.Shortcut))
             {
                 _timer.Reset(100);
                 return;

Source/Game/Spells/Spell.cs

@@ -900,9 +900,9 @@ namespace Game.Spells
                         pos.posX = m_preGeneratedPath.GetActualEndPosition().X;
                         pos.posY = m_preGeneratedPath.GetActualEndPosition().Y;
                         pos.posZ = m_preGeneratedPath.GetActualEndPosition().Z;
+                        dest.Relocate(pos);
                     }
 
-                    dest.Relocate(pos);
                     break;
                 }
                 case Targets.DestCasterGround: