fix(Core/FleeingMovementGenerator): Prevent fear movement from causing characters to fall through the ground (#22451)

3 files changed, 24 insertions, 2 deletions

diff --git a/deps/recastnavigation/Detour/Include/DetourStatus.h b/deps/recastnavigation/Detour/Include/DetourStatus.h
index 8e1bb44b9d..96dcb5b004 100644
--- a/deps/recastnavigation/Detour/Include/DetourStatus.h
+++ b/deps/recastnavigation/Detour/Include/DetourStatus.h
@@ -36,6 +36,7 @@ static const unsigned int DT_BUFFER_TOO_SMALL = 1 << 4;	// Result buffer for the
 static const unsigned int DT_OUT_OF_NODES = 1 << 5;		// Query ran out of nodes during search.
 static const unsigned int DT_PARTIAL_RESULT = 1 << 6;	// Query did not reach the end location, returning best guess. 
 static const unsigned int DT_ALREADY_OCCUPIED = 1 << 7;	// A tile has already been assigned to the given x,y coordinate
+static const unsigned int DT_SLOPE_TOO_STEEP = 1 << 8;  // Surface slope too steep to be walkable.
 
 
 // Returns true of status is success.
diff --git a/src/server/game/Movement/MovementGenerators/FleeingMovementGenerator.cpp b/src/server/game/Movement/MovementGenerators/FleeingMovementGenerator.cpp
index 2547e4ddf3..a4d9867abf 100644
--- a/src/server/game/Movement/MovementGenerators/FleeingMovementGenerator.cpp
+++ b/src/server/game/Movement/MovementGenerators/FleeingMovementGenerator.cpp
@@ -137,9 +137,12 @@ void FleeingMovementGenerator<T>::SetTargetLocation(T* owner)
         _path->Clear();
     }
 
+    if (owner->IsPlayer())
+        _path->SetSlopeCheck(true);
+
     _path->SetPathLengthLimit(30.0f);
     bool result = _path->CalculatePath(destination.GetPositionX(), destination.GetPositionY(), destination.GetPositionZ());
-    if (!result || (_path->GetPathType() & PathType(PATHFIND_NOPATH | PATHFIND_SHORTCUT | PATHFIND_FARFROMPOLY)))
+    if (!result || (_path->GetPathType() & PathType(PATHFIND_NOPATH | PATHFIND_SHORTCUT | PATHFIND_FARFROMPOLY | PATHFIND_NOT_USING_PATH)))
     {
         _timer.Reset(100);
         return;
diff --git a/src/server/game/Movement/MovementGenerators/PathGenerator.cpp b/src/server/game/Movement/MovementGenerators/PathGenerator.cpp
index 015d3973c7..33bd7ec22a 100644
--- a/src/server/game/Movement/MovementGenerators/PathGenerator.cpp
+++ b/src/server/game/Movement/MovementGenerators/PathGenerator.cpp
@@ -564,6 +564,22 @@ void PathGenerator::BuildPointPath(const float* startPoint, const float* endPoin
     }
     else if (pointCount < 2 || dtStatusFailed(dtResult))
     {
+        // If its too steep, just return incomplete path.
+        if (pointCount > 0 && dtResult & DT_SLOPE_TOO_STEEP)
+        {
+            _pathPoints.resize(pointCount);
+            for (uint32 i = 0; i < pointCount; ++i)
+                _pathPoints[i] = G3D::Vector3(pathPoints[i * VERTEX_SIZE + 2], pathPoints[i * VERTEX_SIZE], pathPoints[i * VERTEX_SIZE + 1]);
+
+            NormalizePath();
+
+            // first point is always our current location - we need the next one
+            SetActualEndPosition(_pathPoints[pointCount - 1]);
+
+            _type = PathType(_type | PATHFIND_INCOMPLETE);
+            return;
+        }
+
         // only happens if pass bad data to findStraightPath or navmesh is broken
         // single point paths can be generated here
         /// @todo check the exact cases
@@ -884,7 +900,9 @@ dtStatus PathGenerator::FindSmoothPath(float const* startPos, float const* endPo
 
         if (canCheckSlope && !IsSwimmableSegment(iterPos, steerPos) && !IsWalkableClimb(iterPos, steerPos))
         {
-            return DT_FAILURE;
+            nsmoothPath--;
+            *smoothPathSize = nsmoothPath;
+            return DT_FAILURE | DT_SLOPE_TOO_STEEP;
         }
 
         // Handle end of path and off-mesh links when close enough.