Core/Movement: Fix some undermap issues with random movement/fear/blink (#22937)

* Core/Movement:
- Only move to point if there is a path that is not a shortcut (which will make the unit move through terrain)
- Added new function to check if there is a vmap floor without search distance
- Units that can fly, are underground but far above the vmap floor will stay underground (bronze drakes in tanaris)
- Don't remove PATHFIND_SHORTCUT from path type in some cases

* Core/Object: Ignore UpdateAllowedPositionZ for flying units.

- This will make flying units go through mountains instead of going to the top and back to the bottom to reach you.

* Core/Object: Revert some changes and let MovePositionToFirstCollision deal with a position without ground

* Missing groundZ change for objects on transport

* use CanFly instead of IsFlying

9 files changed, 56 insertions, 20 deletions

diff --git a/src/server/game/Entities/Object/Object.cpp b/src/server/game/Entities/Object/Object.cpp
index 4d605a6afd3..bd3d20f9ff2 100644
--- a/src/server/game/Entities/Object/Object.cpp
+++ b/src/server/game/Entities/Object/Object.cpp
@@ -1414,11 +1414,16 @@ void WorldObject::UpdateGroundPositionZ(float x, float y, float &z) const
         z = new_z + (isType(TYPEMASK_UNIT) ? static_cast<Unit const*>(this)->GetHoverOffset() : 0.0f);
 }
 
-void WorldObject::UpdateAllowedPositionZ(float x, float y, float &z) const
+void WorldObject::UpdateAllowedPositionZ(float x, float y, float &z, float* groundZ) const
 {
     // TODO: Allow transports to be part of dynamic vmap tree
     if (GetTransport())
+    {
+        if (groundZ)
+            *groundZ = z;
+
         return;
+    }
 
     if (Unit const* unit = ToUnit())
     {
@@ -1444,12 +1449,18 @@ void WorldObject::UpdateAllowedPositionZ(float x, float y, float &z) const
                 else if (z < ground_z)
                     z = ground_z;
             }
+
+            if (groundZ)
+                *groundZ = ground_z;
         }
         else
         {
             float ground_z = GetMapHeight(x, y, z) + unit->GetHoverOffset();
             if (z < ground_z)
                 z = ground_z;
+
+            if (groundZ)
+               *groundZ = ground_z;
         }
     }
     else
@@ -1457,6 +1468,9 @@ void WorldObject::UpdateAllowedPositionZ(float x, float y, float &z) const
         float ground_z = GetMapHeight(x, y, z);
         if (ground_z > INVALID_HEIGHT)
             z = ground_z;
+
+        if (groundZ)
+            *groundZ = ground_z;
     }
 }
 
@@ -3283,10 +3297,27 @@ void WorldObject::MovePositionToFirstCollision(Position &pos, float dist, float
         }
     }
 
+    float groundZ = VMAP_INVALID_HEIGHT_VALUE;
     Trinity::NormalizeMapCoord(pos.m_positionX);
     Trinity::NormalizeMapCoord(pos.m_positionY);
-    UpdateAllowedPositionZ(destx, desty, pos.m_positionZ);
+    UpdateAllowedPositionZ(destx, desty, pos.m_positionZ, &groundZ);
     pos.SetOrientation(GetOrientation());
+
+    // position has no ground under it (or is too far away)
+    if (groundZ <= INVALID_HEIGHT)
+    {
+        if (Unit const* unit = ToUnit())
+        {
+            // unit can fly, ignore.
+            if (unit->CanFly())
+                return;
+
+            // fall back to gridHeight if any
+            float gridHeight = GetMap()->GetGridHeight(pos.m_positionX, pos.m_positionY);
+            if (gridHeight > INVALID_HEIGHT)
+                pos.m_positionZ = gridHeight + unit->GetHoverOffset();
+        }
+    }
 }
 
 void WorldObject::SetPhaseMask(uint32 newPhaseMask, bool update)
diff --git a/src/server/game/Entities/Object/Object.h b/src/server/game/Entities/Object/Object.h
index 7b13276a7f8..f8981999f9f 100644
--- a/src/server/game/Entities/Object/Object.h
+++ b/src/server/game/Entities/Object/Object.h
@@ -288,7 +288,7 @@ class TC_GAME_API WorldObject : public Object, public WorldLocation
 
         virtual float GetCombatReach() const { return 0.0f; } // overridden (only) in Unit
         void UpdateGroundPositionZ(float x, float y, float &z) const;
-        void UpdateAllowedPositionZ(float x, float y, float &z) const;
+        void UpdateAllowedPositionZ(float x, float y, float &z, float* groundZ = nullptr) const;
 
         void GetRandomPoint(Position const& srcPos, float distance, float& rand_x, float& rand_y, float& rand_z) const;
         Position GetRandomPoint(Position const& srcPos, float distance) const;
diff --git a/src/server/game/Maps/Map.cpp b/src/server/game/Maps/Map.cpp
index f847fca56e2..2cefeb63532 100644
--- a/src/server/game/Maps/Map.cpp
+++ b/src/server/game/Maps/Map.cpp
@@ -2443,12 +2443,9 @@ float Map::GetHeight(float x, float y, float z, bool checkVMap /*= true*/, float
 {
     // find raw .map surface under Z coordinates
     float mapHeight = VMAP_INVALID_HEIGHT_VALUE;
-    if (GridMap* gmap = const_cast<Map*>(this)->GetGrid(x, y))
-    {
-        float gridHeight = gmap->getHeight(x, y);
-        if (G3D::fuzzyGe(z, gridHeight - GROUND_HEIGHT_TOLERANCE))
-            mapHeight = gridHeight;
-    }
+    float gridHeight = GetGridHeight(x, y);
+    if (G3D::fuzzyGe(z, gridHeight - GROUND_HEIGHT_TOLERANCE))
+        mapHeight = gridHeight;
 
     float vmapHeight = VMAP_INVALID_HEIGHT_VALUE;
     if (checkVMap)
@@ -2470,16 +2467,24 @@ float Map::GetHeight(float x, float y, float z, bool checkVMap /*= true*/, float
             // or if the distance of the vmap height is less the land height distance
             if (vmapHeight > mapHeight || std::fabs(mapHeight - z) > std::fabs(vmapHeight - z))
                 return vmapHeight;
-            else
-                return mapHeight;                           // better use .map surface height
+
+            return mapHeight;                           // better use .map surface height
         }
-        else
-            return vmapHeight;                              // we have only vmapHeight (if have)
+
+        return vmapHeight;                              // we have only vmapHeight (if have)
     }
 
     return mapHeight;                               // explicitly use map data
 }
 
+float Map::GetGridHeight(float x, float y) const
+{
+    if (GridMap* gmap = const_cast<Map*>(this)->GetGrid(x, y))
+        return gmap->getHeight(x, y);
+
+    return VMAP_INVALID_HEIGHT_VALUE;
+}
+
 float Map::GetMinHeight(float x, float y) const
 {
     if (GridMap const* grid = const_cast<Map*>(this)->GetGrid(x, y))
diff --git a/src/server/game/Maps/Map.h b/src/server/game/Maps/Map.h
index 9fa357db44c..ecc13fca277 100644
--- a/src/server/game/Maps/Map.h
+++ b/src/server/game/Maps/Map.h
@@ -543,6 +543,7 @@ class TC_GAME_API Map : public GridRefManager<NGridType>
         float GetWaterOrGroundLevel(uint32 phasemask, float x, float y, float z, float* ground = nullptr, bool swim = false, float collisionHeight = 2.03128f) const; // DEFAULT_COLLISION_HEIGHT in Object.h
         float GetMinHeight(float x, float y) const;
         float GetHeight(float x, float y, float z, bool checkVMap = true, float maxSearchDist = DEFAULT_HEIGHT_SEARCH) const;
+        float GetGridHeight(float x, float y) const;
         float GetHeight(Position const& pos, bool vmap = true, float maxSearchDist = DEFAULT_HEIGHT_SEARCH) const { return GetHeight(pos.GetPositionX(), pos.GetPositionY(), pos.GetPositionZ(), vmap, maxSearchDist); }
         float GetHeight(uint32 phasemask, float x, float y, float z, bool vmap = true, float maxSearchDist = DEFAULT_HEIGHT_SEARCH) const { return std::max<float>(GetHeight(x, y, z, vmap, maxSearchDist), GetGameObjectFloor(phasemask, x, y, z, maxSearchDist)); }
         float GetHeight(uint32 phasemask, Position const& pos, bool vmap = true, float maxSearchDist = DEFAULT_HEIGHT_SEARCH) const { return GetHeight(phasemask, pos.GetPositionX(), pos.GetPositionY(), pos.GetPositionZ(), vmap, maxSearchDist); }
diff --git a/src/server/game/Movement/MovementGenerators/ConfusedMovementGenerator.cpp b/src/server/game/Movement/MovementGenerators/ConfusedMovementGenerator.cpp
index 06d48f9a022..421ca1b8d69 100755
--- a/src/server/game/Movement/MovementGenerators/ConfusedMovementGenerator.cpp
+++ b/src/server/game/Movement/MovementGenerators/ConfusedMovementGenerator.cpp
@@ -100,7 +100,7 @@ bool ConfusedMovementGenerator<T>::DoUpdate(T* owner, uint32 diff)
         }
 
         bool result = _path->CalculatePath(destination.GetPositionX(), destination.GetPositionY(), destination.GetPositionZ());
-        if (!result || (_path->GetPathType() & PATHFIND_NOPATH))
+        if (!result || (_path->GetPathType() & PATHFIND_NOPATH) || (_path->GetPathType() & PATHFIND_SHORTCUT))
         {
             _timer.Reset(100);
             return true;
diff --git a/src/server/game/Movement/MovementGenerators/FleeingMovementGenerator.cpp b/src/server/game/Movement/MovementGenerators/FleeingMovementGenerator.cpp
index 82efaab6001..7c72c50ec10 100644
--- a/src/server/game/Movement/MovementGenerators/FleeingMovementGenerator.cpp
+++ b/src/server/game/Movement/MovementGenerators/FleeingMovementGenerator.cpp
@@ -165,7 +165,7 @@ void FleeingMovementGenerator<T>::SetTargetLocation(T* owner)
     }
 
     bool result = _path->CalculatePath(destination.GetPositionX(), destination.GetPositionY(), destination.GetPositionZ());
-    if (!result || (_path->GetPathType() & PATHFIND_NOPATH))
+    if (!result || (_path->GetPathType() & PATHFIND_NOPATH) || (_path->GetPathType() & PATHFIND_SHORTCUT))
     {
         _timer.Reset(100);
         return;
diff --git a/src/server/game/Movement/MovementGenerators/RandomMovementGenerator.cpp b/src/server/game/Movement/MovementGenerators/RandomMovementGenerator.cpp
index a5b410fc60a..c97c7b389ca 100644
--- a/src/server/game/Movement/MovementGenerators/RandomMovementGenerator.cpp
+++ b/src/server/game/Movement/MovementGenerators/RandomMovementGenerator.cpp
@@ -108,7 +108,7 @@ void RandomMovementGenerator<Creature>::SetRandomLocation(Creature* owner)
     }
 
     bool result = _path->CalculatePath(position.GetPositionX(), position.GetPositionY(), position.GetPositionZ());
-    if (!result || (_path->GetPathType() & PATHFIND_NOPATH))
+    if (!result || (_path->GetPathType() & PATHFIND_NOPATH) || (_path->GetPathType() & PATHFIND_SHORTCUT))
     {
         _timer.Reset(100);
         return;
diff --git a/src/server/game/Movement/PathGenerator.cpp b/src/server/game/Movement/PathGenerator.cpp
index febdae30015..69844b2c15b 100644
--- a/src/server/game/Movement/PathGenerator.cpp
+++ b/src/server/game/Movement/PathGenerator.cpp
@@ -536,14 +536,14 @@ void PathGenerator::BuildPointPath(const float *startPoint, const float *endPoin
         /// @todo check the exact cases
         TC_LOG_DEBUG("maps.mmaps", "++ PathGenerator::BuildPointPath FAILED! path sized %d returned\n", pointCount);
         BuildShortcut();
-        _type = PATHFIND_NOPATH;
+        _type = PathType(_type | PATHFIND_NOPATH);
         return;
     }
     else if (pointCount == _pointPathLimit)
     {
         TC_LOG_DEBUG("maps.mmaps", "++ PathGenerator::BuildPointPath FAILED! path sized %d returned, lower than limit set to %d", pointCount, _pointPathLimit);
         BuildShortcut();
-        _type = PATHFIND_SHORT;
+        _type = PathType(_type | PATHFIND_SHORT);
         return;
     }
 
diff --git a/src/server/game/Spells/Spell.cpp b/src/server/game/Spells/Spell.cpp
index 3e0a5e0d988..a0f35b48b29 100644
--- a/src/server/game/Spells/Spell.cpp
+++ b/src/server/game/Spells/Spell.cpp
@@ -1370,9 +1370,8 @@ void Spell::SelectImplicitCasterDestTargets(SpellEffIndex effIndex, SpellImplici
                 pos.m_positionX = m_preGeneratedPath->GetActualEndPosition().x;
                 pos.m_positionY = m_preGeneratedPath->GetActualEndPosition().y;
                 pos.m_positionZ = m_preGeneratedPath->GetActualEndPosition().z;
+                dest.Relocate(pos);
             }
-
-            dest.Relocate(pos);
             break;
         }
         default: