new-horizons/NewHorizons/Components/Orbital/TrackingOrbitLine.cs

using System;
using UnityEngine;
using Logger = NewHorizons.Utility.Logger;
namespace NewHorizons.Components.Orbital
{
    public class TrackingOrbitLine : OrbitLine
    {
        private Vector3[] _vertices;
        private float _timer;
        private bool _firstTimeEnabled = true;

        public float TrailTime = 120f;

        public override void InitializeLineRenderer()
        {
            _lineRenderer.positionCount = this._numVerts;
        }

        public override void OnValidate()
        {
            if (_numVerts < 0 || _numVerts > 4096)
            {
                _numVerts = Mathf.Clamp(this._numVerts, 0, 4096);
            }
            if (_lineRenderer.positionCount != _numVerts)
            {
                InitializeLineRenderer();
            }
        }

        public override void Start()
        {
            base.Start();
            _vertices = new Vector3[_numVerts];

            base.enabled = true;
            _lineRenderer.enabled = false;
        }

        public override void OnEnterMapView()
        {
            if (_firstTimeEnabled)
            {
                ResetLineVertices();
                _firstTimeEnabled = false;
            }
            _lineRenderer.enabled = true;
        }

        public override void OnExitMapView()
        {
            _lineRenderer.enabled = false;
        }

        public override void Update()
        {
            try
            {
                var primary = _astroObject.GetPrimaryBody();
                Vector3 origin = primary == null ? Locator.GetRootTransform().position : primary.transform.position;

                _timer += Time.deltaTime;
                var updateTime = (TrailTime / (float)_numVerts);

                if (_timer > updateTime)
                {
                    for (int i = _numVerts - 1; i > 0; i--)
                    {
                        var v = _vertices[i - 1];
                        _vertices[i] = new Vector3(v.x, v.y, v.z);
                    }
                    _timer = 0;
                }
                _vertices[0] = transform.parent.position - origin;
                _lineRenderer.SetPositions(_vertices);

                base.transform.position = origin;
                base.transform.rotation = Quaternion.AngleAxis(0f, Vector3.up);

                float num2 = DistanceToTrackingOrbitLine(Locator.GetActiveCamera().transform.position);
                float widthMultiplier = Mathf.Min(num2 * (_lineWidth / 1000f), _maxLineWidth);
                float num3 = _fade ? (1f - Mathf.Clamp01((num2 - _fadeStartDist) / (_fadeEndDist - _fadeStartDist))) : 1f;
                _lineRenderer.widthMultiplier = widthMultiplier;
                _lineRenderer.startColor = new Color(_color.r, _color.g, _color.b, num3 * num3);
            }
            catch (Exception ex)
            {
                Logger.LogError($"Exception in OrbitLine for [{_astroObject?.name}] : {ex.Message}, {ex.StackTrace}");
                enabled = false;
            }
        }

        private float DistanceToTrackingOrbitLine(Vector3 point)
        {
            // Check against 3 points on the line
            var primary = _astroObject.GetPrimaryBody();
            point -= primary.transform.position;
            var dist1 = Vector3.Distance(point, _vertices[0]);
            var dist2 = Vector3.Distance(point, _vertices[(int)(_numVerts / 2)]);
            var dist3 = Vector3.Distance(point, _vertices[_numVerts - 1]);

            return Mathf.Min(new float[] { dist1, dist2, dist3 });
        }

        public void ResetLineVertices()
        {
            var primary = _astroObject.GetPrimaryBody();
            Vector3 origin = primary == null ? Locator.GetRootTransform().position : primary.transform.position;

            base.transform.position = origin;
            base.transform.rotation = Quaternion.AngleAxis(0f, Vector3.up);

            for (int i = _numVerts - 1; i > 0; i--)
            {
                _vertices[i] = transform.parent.position - origin;
            }
            _lineRenderer.SetPositions(_vertices);
        }
    }
}