Core/Movement: Fix LoS issue of NPCs chasing targets

Add Line of Sight checks to WorldObject::GetNearPoint(), fixing to TargetedMovementGenerator not reaching a point with valid LoS to the target and MotionMaster::MoveKnockbackFrom() knocking creatures inside walls.
Remove unused code.

2 files changed, 19 insertions, 103 deletions

diff --git a/src/server/game/Entities/Object/Object.cpp b/src/server/game/Entities/Object/Object.cpp
index 69f7073ce1b..c0a54060298 100644
--- a/src/server/game/Entities/Object/Object.cpp
+++ b/src/server/game/Entities/Object/Object.cpp
@@ -2489,125 +2489,36 @@ void WorldObject::GetNearPoint(WorldObject const* /*searcher*/, float &x, float
 {
     GetNearPoint2D(x, y, distance2d+searcher_size, absAngle);
     z = GetPositionZ();
+    // Should "searcher" be used instead of "this" when updating z coordinate ?
     UpdateAllowedPositionZ(x, y, z);
 
-    /*
     // if detection disabled, return first point
-    if (!sWorld->getIntConfig(CONFIG_DETECT_POS_COLLISION))
-    {
-        UpdateGroundPositionZ(x, y, z);                       // update to LOS height if available
+    if (!sWorld->getBoolConfig(CONFIG_DETECT_POS_COLLISION))
         return;
-    }
 
-    // or remember first point
-    float first_x = x;
-    float first_y = y;
-    bool first_los_conflict = false;                        // first point LOS problems
-
-    // prepare selector for work
-    ObjectPosSelector selector(GetPositionX(), GetPositionY(), GetObjectSize(), distance2d+searcher_size);
-
-    // adding used positions around object
-    {
-        CellCoord p(Trinity::ComputeCellCoord(GetPositionX(), GetPositionY()));
-        Cell cell(p);
-        cell.SetNoCreate();
-
-        Trinity::NearUsedPosDo u_do(*this, searcher, absAngle, selector);
-        Trinity::WorldObjectWorker<Trinity::NearUsedPosDo> worker(this, u_do);
-
-        TypeContainerVisitor<Trinity::WorldObjectWorker<Trinity::NearUsedPosDo>, GridTypeMapContainer  > grid_obj_worker(worker);
-        TypeContainerVisitor<Trinity::WorldObjectWorker<Trinity::NearUsedPosDo>, WorldTypeMapContainer > world_obj_worker(worker);
-
-        CellLock<GridReadGuard> cell_lock(cell, p);
-        cell_lock->Visit(cell_lock, grid_obj_worker,  *GetMap(), *this, distance2d);
-        cell_lock->Visit(cell_lock, world_obj_worker, *GetMap(), *this, distance2d);
-    }
-
-    // maybe can just place in primary position
-    if (selector.CheckOriginal())
-    {
-        UpdateGroundPositionZ(x, y, z);                       // update to LOS height if available
-
-        if (IsWithinLOS(x, y, z))
-            return;
-
-        first_los_conflict = true;                          // first point have LOS problems
-    }
-
-    float angle;                                            // candidate of angle for free pos
-
-    // special case when one from list empty and then empty side preferred
-    if (selector.FirstAngle(angle))
-    {
-        GetNearPoint2D(x, y, distance2d, absAngle+angle);
-        z = GetPositionZ();
-        UpdateGroundPositionZ(x, y, z);                       // update to LOS height if available
-
-        if (IsWithinLOS(x, y, z))
-            return;
-    }
-
-    // set first used pos in lists
-    selector.InitializeAngle();
-
-    // select in positions after current nodes (selection one by one)
-    while (selector.NextAngle(angle))                        // angle for free pos
-    {
-        GetNearPoint2D(x, y, distance2d, absAngle+angle);
-        z = GetPositionZ();
-        UpdateGroundPositionZ(x, y, z);                       // update to LOS height if available
-
-        if (IsWithinLOS(x, y, z))
-            return;
-    }
-
-    // BAD NEWS: not free pos (or used or have LOS problems)
-    // Attempt find _used_ pos without LOS problem
-
-    if (!first_los_conflict)
-    {
-        x = first_x;
-        y = first_y;
-
-        UpdateGroundPositionZ(x, y, z);                       // update to LOS height if available
+    // return if the point is already in LoS
+    if (IsWithinLOS(x, y, z))
         return;
-    }
-
-    // special case when one from list empty and then empty side preferred
-    if (selector.IsNonBalanced())
-    {
-        if (!selector.FirstAngle(angle))                     // _used_ pos
-        {
-            GetNearPoint2D(x, y, distance2d, absAngle+angle);
-            z = GetPositionZ();
-            UpdateGroundPositionZ(x, y, z);                   // update to LOS height if available
-
-            if (IsWithinLOS(x, y, z))
-                return;
-        }
-    }
 
-    // set first used pos in lists
-    selector.InitializeAngle();
+    // remember first point
+    float first_x = x;
+    float first_y = y;
+    float first_z = z;
 
-    // select in positions after current nodes (selection one by one)
-    while (selector.NextUsedAngle(angle))                    // angle for used pos but maybe without LOS problem
+    // loop in a circle to look for a point in LoS using small steps
+    for (float angle = M_PI / 8; angle < M_PI * 2; angle += M_PI / 8)
     {
-        GetNearPoint2D(x, y, distance2d, absAngle+angle);
+        GetNearPoint2D(x, y, distance2d + searcher_size, absAngle + angle);
         z = GetPositionZ();
-        UpdateGroundPositionZ(x, y, z);                       // update to LOS height if available
-
+        UpdateAllowedPositionZ(x, y, z);
         if (IsWithinLOS(x, y, z))
             return;
     }
 
-    // BAD BAD NEWS: all found pos (free and used) have LOS problem :(
+    // still not in LoS, give up and return first position found
     x = first_x;
     y = first_y;
-
-    UpdateGroundPositionZ(x, y, z);                           // update to LOS height if available
-    */
+    z = first_z;
 }
 
 void WorldObject::GetClosePoint(float &x, float &y, float &z, float size, float distance2d /*= 0*/, float angle /*= 0*/) const
diff --git a/src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.cpp b/src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.cpp
index 28e58c87323..c59762066ae 100644
--- a/src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.cpp
+++ b/src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.cpp
@@ -159,10 +159,15 @@ bool TargetedMovementGeneratorMedium<T, D>::DoUpdate(T* owner, uint32 time_diff)
             if (TransportBase* transport = owner->GetDirectTransport())
                 transport->CalculatePassengerPosition(dest.x, dest.y, dest.z);
 
+        // First check distance
         if (owner->GetTypeId() == TYPEID_UNIT && owner->ToCreature()->CanFly())
             targetMoved = !i_target->IsWithinDist3d(dest.x, dest.y, dest.z, allowed_dist);
         else
             targetMoved = !i_target->IsWithinDist2d(dest.x, dest.y, allowed_dist);
+
+        // then, if the target is in range, check also Line of Sight.
+        if (!targetMoved)
+            targetMoved = !i_target->IsWithinLOSInMap(owner);
     }
 
     if (i_recalculateTravel || targetMoved)