Movement.cs

// we want to support different movement types:
//   * Navmesh
//   * Character Controller
//   (* Rigidbody)
//   etc.
//
// => Entity.cs needs some common functionality to work with all of them.
// => this makes swapping out movement systems very easy!
using UnityEngine;
using Mirror;

namespace uMMORPG
{
    public abstract class Movement : NetworkBehaviour
    {
        // velocity is useful for animations etc.
        // => not a property because most movement systems manage their own
        //    'velocity' variable internally, and set them too (we want readonly)
        public abstract Vector3 GetVelocity();

        // currently moving? important for certain skills that can't be casted
        // while moving, etc.
        public abstract bool IsMoving();

        // .speed lives in Entity and depends on level, skills, equip, etc.
        // => in here we simply apply it (e.g. to NavMeshAgent.speed)
        public abstract void SetSpeed(float speed);

        // look at a transform while only rotating on the Y axis (to avoid weird
        // tilts)
        // => abstract because not all movement systems might use the same method.
        public abstract void LookAtY(Vector3 position);

        // reset all movement. just stop and stand.
        public abstract void Reset();

        // warp to a different area
        // => setting transform.position isn't good enough. for example,
        //    NavMeshAgent movement always needs to call agent.Warp. otherwise the
        //    agent might get stuck on a tree inbetween position and destination etc
        public abstract void Warp(Vector3 destination);

        // does this movement system support navigation / pathfinding?
        // -> some systems might not support it never
        // -> some might support it while grounded, etc.
        public abstract bool CanNavigate();

        // navigate along a path to a destination
        public abstract void Navigate(Vector3 destination, float stoppingDistance);

        // when spawning we need to know if the last saved position is still valid
        // for this type of movement.
        // * NavMesh movement should only spawn on the NavMesh
        // * CharacterController movement should spawn on a Mesh, etc.
        public abstract bool IsValidSpawnPoint(Vector3 position);

        // sometimes we need to know the nearest valid destination for a point that
        // might be behind a wall, etc.
        public abstract Vector3 NearestValidDestination(Vector3 destination);

        // should we auto look-at the target during combat?
        // e.g. if it moves behind us.
        // -> usually good for navigation movement systems
        // -> usually not good for character controller movement systems
        public abstract bool DoCombatLookAt();
    }
}