PlayerMountControl.cs

// put all mount control code into a separate component.
// => for consistency with PetControl
// => if we need mount inventories, then we can put the Cmds in here too later
using UnityEngine;
using Mirror;

namespace uMMORPG
{
    [DisallowMultipleComponent]
    public class PlayerMountControl : NetworkBehaviour
    {
        [Header("Mount")]
        public Transform meshToOffsetWhenMounted;
        public float seatOffsetY = -1;

        // 'Mount' can't be SyncVar so we use [SyncVar] GameObject and wrap it
        [SyncVar, HideInInspector] public Mount activeMount;

        void LateUpdate()
        {
            // follow mount's seat position if mounted
            // (on server too, for correct collider position and calculations)
            ApplyMountSeatOffset();
        }

        public bool IsMounted()
        {
            return activeMount != null && activeMount.health.current > 0;
        }

        void ApplyMountSeatOffset()
        {
            if (meshToOffsetWhenMounted != null)
            {
                // apply seat offset if on mount (not a dead one), reset otherwise
                if (activeMount != null && activeMount.health.current > 0)
                    meshToOffsetWhenMounted.transform.position = activeMount.seat.position + Vector3.up * seatOffsetY;
                else
                    meshToOffsetWhenMounted.transform.localPosition = Vector3.zero;
            }
        }
    }
}