fix(Core/Movement): followers match their target's motion speed (#25085)

Co-authored-by: killerwife <killerwife@gmail.com>

src/server/game/Entities/Object/Object.cpp

@@ -995,6 +995,30 @@ std::string Object::GetDebugInfo() const
     return sstr.str();
 }
 
+UnitMoveType MovementInfo::GetSpeedType(uint32 moveFlags)
+{
+    if (moveFlags & MOVEMENTFLAG_FLYING)
+    {
+        if (moveFlags & MOVEMENTFLAG_BACKWARD)
+            return MOVE_FLIGHT_BACK;
+
+        return MOVE_FLIGHT;
+    }
+    else if (moveFlags & MOVEMENTFLAG_SWIMMING)
+    {
+        if (moveFlags & MOVEMENTFLAG_BACKWARD)
+            return MOVE_SWIM_BACK;
+
+        return MOVE_SWIM;
+    }
+    else if (moveFlags & MOVEMENTFLAG_WALKING)
+        return MOVE_WALK;
+    else if (moveFlags & MOVEMENTFLAG_BACKWARD)
+        return MOVE_RUN_BACK;
+
+    return MOVE_RUN;
+}
+
 void MovementInfo::OutDebug()
 {
     LOG_INFO("movement", "MOVEMENT INFO");

src/server/game/Entities/Object/Object.h

@@ -31,6 +31,7 @@
 #include "ObjectGuid.h"
 #include "Optional.h"
 #include "Position.h"
+#include "UnitDefines.h"
 #include "UpdateData.h"
 #include "UpdateMask.h"
 #include "ObjectVisibilityContainer.h"
@@ -344,6 +345,9 @@ struct MovementInfo
     void RemoveMovementFlag(uint32 flag) { flags &= ~flag; }
     [[nodiscard]] bool HasMovementFlag(uint32 flag) const { return flags & flag; }
 
+    [[nodiscard]] UnitMoveType GetSpeedType() const { return GetSpeedType(flags); }
+    [[nodiscard]] static UnitMoveType GetSpeedType(uint32 moveFlags);
+
     [[nodiscard]] uint16 GetExtraMovementFlags() const { return flags2; }
     void AddExtraMovementFlag(uint16 flag) { flags2 |= flag; }
     [[nodiscard]] bool HasExtraMovementFlag(uint16 flag) const { return flags2 & flag; }

src/server/game/Entities/Unit/UnitDefines.h

@@ -15,6 +15,9 @@
  * with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
+#ifndef ACORE_UNITDEFINES_H
+#define ACORE_UNITDEFINES_H
+
 #include "Define.h"
 #include "EnumFlag.h"
 
@@ -487,3 +490,5 @@ enum SplineType
     SPLINETYPE_FACING_TARGET    = 3,
     SPLINETYPE_FACING_ANGLE     = 4
 };
+
+#endif // ACORE_UNITDEFINES_H

src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.cpp

@@ -430,20 +430,27 @@ void ChaseMovementGenerator<T>::MovementInform(T* owner)
 
 //-----------------------------------------------//
 
+static float GetTargetSpeedInMotion(Unit* target)
+{
+    if (!target->movespline->Finalized())
+        return target->movespline->Velocity();
+
+    return target->GetSpeed(target->m_movementInfo.GetSpeedType());
+}
+
 static Optional<float> GetVelocity(Unit* owner, Unit* target, G3D::Vector3 const& dest, bool playerPet)
 {
     Optional<float> speed = {};
-    if (!owner->IsInCombat() && !owner->IsVehicle() && !owner->HasUnitFlag(UNIT_FLAG_POSSESSED) &&
-        (owner->IsPet() || owner->IsGuardian() || owner->GetGUID() == target->GetCritterGUID() || owner->GetCharmerOrOwnerGUID() == target->GetGUID()))
-    {
-        uint32 moveFlags = target->GetUnitMovementFlags();
-        if (target->IsWalking())
-        {
-            moveFlags |= MOVEMENTFLAG_WALKING;
-        }
+    if (owner->IsInCombat() || owner->IsVehicle() || owner->HasUnitFlag(UNIT_FLAG_POSSESSED))
+        return speed;
+
+    bool isPetLike = owner->IsPet() || owner->IsGuardian() || owner->GetGUID() == target->GetCritterGUID() || owner->GetCharmerOrOwnerGUID() == target->GetGUID();
+
+    // For pets/guardians/critters or creature-to-creature follow: sync with target's speed
+    if (isPetLike || (owner->IsCreature() && target->IsCreature()))
+    {
+        speed = GetTargetSpeedInMotion(target);
 
-        UnitMoveType moveType = Movement::SelectSpeedType(moveFlags);
-        speed = target->GetSpeed(moveType);
         if (playerPet)
         {
             float distance = owner->GetDistance2d(dest.x, dest.y) - target->GetObjectSize() - (*speed / 2.f);
@@ -462,7 +469,7 @@ static Position const PredictPosition(Unit* target)
 {
     Position pos = target->GetPosition();
     // 0.5 - it's time (0.5 sec) between starting movement opcode (e.g. MSG_MOVE_START_FORWARD) and MSG_MOVE_HEARTBEAT sent by client
-    float speed = target->GetSpeed(Movement::SelectSpeedType(target->GetUnitMovementFlags())) * 0.5f;
+    float speed = target->GetSpeed(target->m_movementInfo.GetSpeedType()) * 0.5f;
     float orientation = target->GetOrientation();
 
     if (target->m_movementInfo.HasMovementFlag(MOVEMENTFLAG_FORWARD))

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

@@ -29,31 +29,7 @@ namespace Movement
 {
     UnitMoveType SelectSpeedType(uint32 moveFlags)
     {
-        if (moveFlags & MOVEMENTFLAG_FLYING)
-        {
-            if (moveFlags & MOVEMENTFLAG_BACKWARD /*&& speed_obj.flight >= speed_obj.flight_back*/)
-                return MOVE_FLIGHT_BACK;
-            else
-                return MOVE_FLIGHT;
-        }
-        else if (moveFlags & MOVEMENTFLAG_SWIMMING)
-        {
-            if (moveFlags & MOVEMENTFLAG_BACKWARD /*&& speed_obj.swim >= speed_obj.swim_back*/)
-                return MOVE_SWIM_BACK;
-            else
-                return MOVE_SWIM;
-        }
-        else if (moveFlags & MOVEMENTFLAG_WALKING)
-        {
-            //if (speed_obj.run > speed_obj.walk)
-            return MOVE_WALK;
-        }
-        else if (moveFlags & MOVEMENTFLAG_BACKWARD /*&& speed_obj.run >= speed_obj.run_back*/)
-            return MOVE_RUN_BACK;
-
-        // Flying creatures use MOVEMENTFLAG_CAN_FLY or MOVEMENTFLAG_DISABLE_GRAVITY
-        // Run speed is their default flight speed.
-        return MOVE_RUN;
+        return MovementInfo::GetSpeedType(moveFlags);
     }
 
     int32 MoveSplineInit::Launch()