Core/Movement: Fix LoS issue of NPCs chasing targets

Add Line of Sight checks to ChaseMovementGenerator::Update(), fixing to ChaseMovementGenerator not reaching a point with valid LoS to the target.

Fix re-implements 8927a042536d4671e94ad901e9209efcf78ffa2c after 2a84562dc85516f432bb1e5de9add23c28b26ce4 partially removed it.

Fix #23724

(cherry picked from commit 215a6cee24896f2def2a5af390c089ac1d947e65)

2 files changed, 15 insertions, 1 deletions

diff --git a/src/server/game/Movement/MovementGenerators/ChaseMovementGenerator.cpp b/src/server/game/Movement/MovementGenerators/ChaseMovementGenerator.cpp
index 0e22919e155..9cd58ee0f82 100644
--- a/src/server/game/Movement/MovementGenerators/ChaseMovementGenerator.cpp
+++ b/src/server/game/Movement/MovementGenerators/ChaseMovementGenerator.cpp
@@ -44,7 +44,11 @@ static bool PositionOkay(Unit* owner, Unit* target, Optional<float> minDistance,
         return false;
     if (maxDistance && distSq > square(*maxDistance))
         return false;
-    return !angle || angle->IsAngleOkay(target->GetRelativeAngle(owner));
+    if (angle && !angle->IsAngleOkay(target->GetRelativeAngle(owner)))
+        return false;
+    if (!owner->IsWithinLOSInMap(target))
+        return false;
+    return true;
 }
 
 static void DoMovementInform(Unit* owner, Unit* target)
diff --git a/src/server/game/Movement/PathGenerator.cpp b/src/server/game/Movement/PathGenerator.cpp
index 33e6f786c75..f179579b5e3 100644
--- a/src/server/game/Movement/PathGenerator.cpp
+++ b/src/server/game/Movement/PathGenerator.cpp
@@ -927,6 +927,7 @@ void PathGenerator::ShortenPathUntilDist(G3D::Vector3 const& target, float dist)
         return;
 
     size_t i = _pathPoints.size()-1;
+    float x, y, z, collisionHeight = _sourceUnit->GetCollisionHeight();
     // find the first i s.t.:
     //  - _pathPoints[i] is still too close
     //  - _pathPoints[i-1] is too far away
@@ -937,6 +938,15 @@ void PathGenerator::ShortenPathUntilDist(G3D::Vector3 const& target, float dist)
         if ((_pathPoints[i-1] - target).squaredLength() >= distSq)
             break; // bingo!
 
+        // check if the shortened path is still in LoS with the target
+        _sourceUnit->GetHitSpherePointFor({ _pathPoints[i - 1].x, _pathPoints[i - 1].y, _pathPoints[i - 1].z + collisionHeight }, x, y, z);
+        if (!_sourceUnit->GetMap()->isInLineOfSight(_sourceUnit->GetPhaseShift(), x, y, z, _pathPoints[i - 1].x, _pathPoints[i - 1].y, _pathPoints[i - 1].z + collisionHeight, LINEOFSIGHT_ALL_CHECKS, VMAP::ModelIgnoreFlags::Nothing))
+        {
+            // whenver we find a point that is not in LoS anymore, simply use last valid path
+            _pathPoints.resize(i + 1);
+            return;
+        }
+
         if (!--i)
         {
             // no point found that fulfills the condition