Create Spline From Points

using System;
using System.Collections.Generic;
using Unity.Mathematics;
using UnityEngine;
using UnityEngine.Splines;

namespace sc.modeling.splines.runtime.auxiliary
{
    public class CreateSplineFromPoints : MonoBehaviour
    {
        [Header("Input")]
        [Tooltip("Positional points in local-space")]
        public List<float3> points = new List<float3>()
        {
            new float3(-1f, 0f, -5f),
            new float3(1f, 0f, -2.5f),
            new float3(-1f, 0f, 0),
            new float3(1f, 0f, 2.5f),
            new float3(-1f, 0f, 5f),
        };

        [Space]

        [Header("Output")]
        public SplineContainer splineContainer;
        public bool closed = false;
        [Tooltip("The error threshold to use. Represents the largest distance between any of the provided points and the curve.")]
        public float errorThreshold = 0.85f;

        private void Reset()
        {
            splineContainer = GetComponent<SplineContainer>();
            if (!splineContainer) splineContainer = this.gameObject.AddComponent<SplineContainer>();
        }

        private void OnValidate()
        {
            if (!splineContainer)
            {
                throw new Exception("Failed to create a spline from a position list. No SplineContainer is assigned to the component");
            }
            int pointCount = points.Count;

            if (pointCount < 2)
            {
                throw new Exception("Failed to create a spline from a position list. At least 2 points need to be provided");
            }

            //First, delete all existing splines
            for (int s = 0; s < splineContainer.Splines.Count; s++)
            {
                splineContainer.RemoveSpline(splineContainer.Splines[s]);
            }

            var pointsCopy = new List<float3>(points);
            //Convert points from world-space to local-space
            for (int i = 0; i < points.Count; i++)
            {
                pointsCopy[i] = splineContainer.transform.InverseTransformPoint(points[i]);
            }

            SplineUtility.FitSplineToPoints(pointsCopy, errorThreshold, closed, out var spline);

            //Adding a spline automatically rebuilds the mesh
            splineContainer.AddSpline(spline);
        }

        private void OnDrawGizmosSelected()
        {
            if (!splineContainer) return;

            Gizmos.matrix = splineContainer.transform.localToWorldMatrix;
            foreach (Vector3 p in points)
            {
                Gizmos.DrawSphere(p, 0.25f);
            }
        }
    }
}