3DTD/Assets/Scripts/Tower/AimTower.cs

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class AimTower : Tower
{
    [SerializeField] protected Barrel barrel;
    [SerializeField] protected EditableArc horizontalArc;
    [SerializeField] protected EditableArc verticalArc;

    [Header("Trajectory")]
    [SerializeField] private float spaceBetweenGhosts = 0.5f;
    [SerializeField] private int trajectoryBounces = 3;
    private const float k_trajectory_maxdist = 100f;
    private List<GameObject> ghosts = new();
    [SerializeField] private GameObject ghostPrefab;
    [SerializeField] private LineRenderer trajectoryLine;
    [SerializeField] private int trajectoryObjectPoolSize = 25;
    [SerializeField] private LayerMask wallMask;
    private int poolIdx = 0;

    public Vector3 AimDirection => barrel.transform.forward;
    public Vector2 HorizontalRotationMinMax => horizontalArc.RotationMinMax;
    public Vector2 VerticalRotationMinMax => verticalArc.RotationMinMax;
    public float HorizontalRotation => horizontalArc.Value;
    public float VerticalRotation => verticalArc.Value;

    public override void Placed()
    {
        base.Placed();

        horizontalArc.Value.AddListener(UpdateBarrelRotation);
        verticalArc.Value.AddListener(UpdateBarrelRotation);

        horizontalArc.Value.AddListener(UpdateTrajectory);
        verticalArc.Value.AddListener(UpdateTrajectory);

        horizontalArc.Value.AddListener(SnapVerticalToHorizontal);

        UpdateTrajectory();
        UpdateBarrelRotation();
    }

    public override void TowerSelected(bool selected)
    {
        base.TowerSelected(selected);

        horizontalArc.gameObject.SetActive(selected);
        verticalArc.gameObject.SetActive(selected);
        trajectoryLine.gameObject.SetActive(selected);
        UpdateTrajectory();
    }

    protected override void OnDestroy()
    {
        horizontalArc.Value.RemoveListener(UpdateBarrelRotation);
        verticalArc.Value.RemoveListener(UpdateBarrelRotation);
        horizontalArc.Value.RemoveListener(SnapVerticalToHorizontal);
    }

    private void UpdateBarrelRotation(float unused) => UpdateBarrelRotation();

    // Rotate barrel to match rotation
    private void UpdateBarrelRotation()
    {
        barrel.transform.localRotation = Quaternion.Euler(-verticalArc.Value, horizontalArc.Value, 0f);
    }

    private void SnapVerticalToHorizontal(float horizontalAngle)
    {
        verticalArc.transform.rotation = Quaternion.Euler(verticalArc.transform.rotation.eulerAngles.x, horizontalAngle, verticalArc.transform.rotation.eulerAngles.z);
    }

    private void UpdateTrajectory(float unused) => UpdateTrajectory();

    private void UpdateTrajectory()
    {
        foreach (var ghost in ghosts)
        {
            ghost.SetActive(false);
        }
        if (!this.selected) return;

        Vector3 origin = barrel.Tip.position;
        Vector3 dir = barrel.transform.forward;
        List<Vector3> pointsInTrajectory = new();
        pointsInTrajectory.Add(origin);
        for (int i = 0; i < trajectoryBounces; i++)
        {
            Debug.DrawRay(origin, dir.normalized * k_trajectory_maxdist, Color.red, 5f);
            RaycastHit hit;
            if (!Physics.Raycast(origin, dir, out hit, k_trajectory_maxdist, wallMask))
                break;

            pointsInTrajectory.Add(hit.point);
            dir = Vector3.Reflect(dir, hit.normal);
            origin = hit.point;
        }

        trajectoryLine.positionCount = pointsInTrajectory.Count;
        trajectoryLine.SetPositions(pointsInTrajectory.ToArray());

        // Build trajectory
        for (int i = 0; i < pointsInTrajectory.Count - 1; i++)
        {
            Vector3 point1 = pointsInTrajectory[i];
            Vector3 point2 = pointsInTrajectory[i + 1];

            Vector3 trajDir = (point2 - point1).normalized;
            float dist = Vector3.Distance(point1, point2);
            for (float j = 0; j < dist; j += spaceBetweenGhosts)
            {
                Vector3 ghostPos = point1 + trajDir * j;

                // Use object pool or spawn new
                if (ghosts.Count >= trajectoryObjectPoolSize)
                {
                    ghosts[poolIdx].transform.position = ghostPos;
                    ghosts[poolIdx].SetActive(true);
                    poolIdx = (poolIdx + 1) % trajectoryObjectPoolSize;
                }
                else
                {
                    var ghost = Instantiate(ghostPrefab);
                    ghost.transform.position = ghostPos;
                    ghost.transform.parent = transform;
                    ghosts.Add(ghost);
                }
            }
        }
    }
}