feat(Core/CreatureAI): improve npc position during the combat (#3369)

+ tangent equation to find correct angle and distance when moving

+ implemented proper backward

* Improved performance + random angle margin

* chore: add tollerance calculation in instance

* improved LOS checks with movements

* implemented collisions using raycast (imported by TC)

+ improved collision detection for CanReachPositionAndGetCoords

+ improved collision check

+ set correct flags for the backward movement

+ first implementation of slope angle (to improve)

Co-authored-by: Yehonal <yehonal.azeroth@gmail.com>

src/server/game/Movement/Spline/MoveSplineInit.cpp

@@ -79,7 +79,16 @@ namespace Movement
         move_spline.onTransport = transport;
 
         uint32 moveFlags = unit->m_movementInfo.GetMovementFlags();
-        moveFlags |= (MOVEMENTFLAG_SPLINE_ENABLED | MOVEMENTFLAG_FORWARD);
+        moveFlags |= MOVEMENTFLAG_SPLINE_ENABLED;
+
+        if (!args.flags.orientationInversed)
+        {
+            moveFlags = (moveFlags & ~(MOVEMENTFLAG_BACKWARD)) | MOVEMENTFLAG_FORWARD;
+        }
+        else
+        {
+            moveFlags = (moveFlags & ~(MOVEMENTFLAG_FORWARD)) | MOVEMENTFLAG_BACKWARD;
+        }
 
         if (moveFlags & MOVEMENTFLAG_ROOT)
             moveFlags &= ~MOVEMENTFLAG_MASK_MOVING;