Dice

using UnityEngine;

namespace YounGenTech {
    public class Dice : MonoBehaviour {

        public Vector3[] side = new Vector3[] { Vector3.forward, Vector3.down, Vector3.left, Vector3.right, Vector3.up, Vector3.back };

        public int currentTopSide = -1;

        void Update() {
            currentTopSide = GetTopSide();
        }

        public int GetTopSide() {
            return GetNearestToDirection(Vector3.up);
        }

        public int GetNearestToDirection(Vector3 direction) {
            int index = -1;
            float highestDot = 0;

            for(int i = 0; i < side.Length; i++) {
                float dot = Vector3.Dot(direction, transform.TransformDirection(side[i]));

                if(dot > highestDot) {
                    index = i;
                    highestDot = dot;
                }
            }

            return index;
        }

        void OnDrawGizmos() {
            if(currentTopSide > -1 && currentTopSide < side.Length) {
                Gizmos.color = Color.yellow;
                Gizmos.DrawRay(transform.position, transform.TransformDirection(side[currentTopSide]));
            }
        }
    }
}