RoadRunner/Assets/Gley/UrbanAssets/Scripts/Editor/WaypointsDraw/SplitBezierIntoPoints.cs

using Gley.UrbanSystem.Internal;
using System.Collections.Generic;
using UnityEngine;

namespace Gley.UrbanSystem.Editor
{
    internal class SplitBezierIntoPoints
    {
        private const string _helpingPointsHolderName = "HelpingPointsHolder";


        internal static List<Transform> CreatePoints(RoadBase road)
        {
            GameObject helpingPointsHolder = MonoBehaviourUtilities.CreateGameObject(_helpingPointsHolderName, road.transform, road.transform.position, true);
            List<Transform> helpingPoints = new List<Transform>();
            for (int i = 0; i < road.path.NumSegments; i++)
            {
                AddSegmentPoints(road.path, i, road.waypointDistance, helpingPointsHolder, helpingPoints, road.name, road.positionOffset);
            }
            RotateHelpingPoints(helpingPoints);
            return helpingPoints;
        }


        private static void AddSegmentPoints(Path path, int segmentIndex, float waypointDistance, GameObject helpingPointsHolder, List<Transform> helpingPoints, string roadName, Vector3 offset)
        {
            Vector3[] p = path.GetPointsInSegment(segmentIndex, Vector3.zero);
            float controlNetLength = Vector3.Distance(p[0], p[1]) + Vector3.Distance(p[1], p[2]) + Vector3.Distance(p[2], p[3]);
            float estimatedCurveLength = Vector3.Distance(p[0], p[3]) + controlNetLength / 2f;
            float nrOfWaypoints = estimatedCurveLength / waypointDistance;
            float step = 1 / nrOfWaypoints;
            float t = 0;

            while (t < 1)
            {
                AddHelpingPoint(helpingPointsHolder.transform, helpingPoints, BezierCurve.CalculateCubicBezierPoint(t, p[0], p[1], p[2], p[3]), roadName, offset);
                t += step;
            }
            AddHelpingPoint(helpingPointsHolder.transform, helpingPoints, BezierCurve.CalculateCubicBezierPoint(1, p[0], p[1], p[2], p[3]), roadName, offset);
        }


        private static void AddHelpingPoint(Transform holder, List<Transform> helpingPoints, Vector3 position, string roadName, Vector3 offset)
        {
            if (helpingPoints.Count > 0)
            {
                if (Vector3.Distance(helpingPoints[helpingPoints.Count - 1].position, position) < 0.01f)
                {
                    return;
                }
            }
            GameObject go = MonoBehaviourUtilities.CreateGameObject(roadName + "_" + UrbanSystemConstants.WaypointNamePrefix + helpingPoints.Count, holder, position + offset, true);
            helpingPoints.Add(go.transform);
        }


        private static void RotateHelpingPoints(List<Transform> helpingPoints)
        {
            Vector3 direction;
            for (int i = 1; i < helpingPoints.Count; i++)
            {
                direction = helpingPoints[i].position - helpingPoints[i - 1].position;
                helpingPoints[i - 1].rotation = Quaternion.LookRotation(direction);
            }
            helpingPoints[helpingPoints.Count - 1].rotation = helpingPoints[helpingPoints.Count - 2].rotation;
        }
    }
}