turret tutorial scripts

Gun.cs

using UnityEngine;


public class Gun : MonoBehaviour
{
    public GameObject shotPrefab;
    public Transform[] gunPoints;
    public float fireRate;

    bool firing;
    float fireTimer;

    int gunPointIndex;

    void Update()
    {
        if (firing)
        {
            while (fireTimer >= 1 / fireRate)
            {
                SpawnShot();
                fireTimer -= 1 / fireRate;
            }

            fireTimer += Time.deltaTime;
            firing = false;
        }
        else
        {
            if (fireTimer < 1 / fireRate)
            {
                fireTimer += Time.deltaTime;
            }
            else
            {
                fireTimer = 1 / fireRate;
            }
        }
    }

    void SpawnShot()
    {
        var gunPoint = gunPoints[gunPointIndex++];
        Instantiate(shotPrefab, gunPoint.position, gunPoint.rotation);
        gunPointIndex %= gunPoints.Length;
    }

    public void Fire()
    {
        firing = true;
    }
}

MountPoint.cs

using UnityEditor;
using UnityEngine;


public class MountPoint : MonoBehaviour
{
    [Range(0, 360f)]
    public float angleLimit = 90f;
    [Range(0, 360f)]
    public float aimTolerance = 1f;
    public float turnSpeed = 90f;

    Transform turret;

    void OnDrawGizmos()
    {
#if UNITY_EDITOR
        var range = 20f;
        var hardpoint = transform;
        var from = Quaternion.AngleAxis(-angleLimit / 2, hardpoint.up) * hardpoint.forward;

        Handles.color = new Color(0, 1, 0, .2f);
        Handles.DrawSolidArc(hardpoint.position, hardpoint.up, from, angleLimit, range);
#endif
    }

    void Awake()
    {
        turret = transform.GetChild(0);
    }

    public bool Aim(Vector3 targetPoint)
    {
        return Aim(targetPoint, out _);
    }

    public bool Aim(Vector3 targetPoint, out bool reachAngleLimit)
    {
        reachAngleLimit = default;
        var hardpoint = transform;
        var los = targetPoint - hardpoint.position;
        var halfAngle = angleLimit / 2;
        var losOnPlane = Vector3.ProjectOnPlane(los, hardpoint.up);
        var deltaAngle = Vector3.SignedAngle(hardpoint.forward, losOnPlane, hardpoint.up);

        if (Mathf.Abs(deltaAngle) > halfAngle)
        {
            reachAngleLimit = true;
            losOnPlane = hardpoint.rotation * Quaternion.Euler(0, Mathf.Clamp(deltaAngle, -halfAngle, halfAngle), 0) * Vector3.forward;
        }

        var targetRotation = Quaternion.LookRotation(losOnPlane, hardpoint.up);
        var aimed = !reachAngleLimit && Quaternion.Angle(turret.rotation, targetRotation) < aimTolerance;
        turret.rotation = Quaternion.RotateTowards(turret.rotation, targetRotation, turnSpeed * Time.deltaTime);

        return aimed;
    }
}

Shot.cs

using UnityEngine;

public class Shot : MonoBehaviour
{
    public GameObject hitPrefab;
    public GameObject muzzlePrefab;
    public float speed;

    Rigidbody rb;
    Vector3 velocity;

    void Awake()
    {
        TryGetComponent(out rb);
    }

    void Start()
    {
        var muzzleEffect = Instantiate(muzzlePrefab, transform.position, transform.rotation);
        Destroy(muzzleEffect, 5f);
        velocity = transform.forward * speed;
    }

    void FixedUpdate()
    {
        var displacement = velocity * Time.deltaTime;
        rb.MovePosition(rb.position + displacement);
    }

    void OnCollisionEnter(Collision other)
    {
        var hitEffect = Instantiate(hitPrefab, other.GetContact(0).point, Quaternion.identity);
        Destroy(hitEffect, 5f);
        Destroy(gameObject);
    }
}

Turret.cs

using UnityEditor;
using UnityEngine;


public class Turret : MonoBehaviour
{
    public Gun gun;
    public MountPoint[] mountPoints;
    public Transform target;

    void OnDrawGizmos()
    {
#if UNITY_EDITOR
        if (!target) return;

        var dashLineSize = 2f;

        foreach (var mountPoint in mountPoints)
        {
            var hardpoint = mountPoint.transform;
            var from = Quaternion.AngleAxis(-mountPoint.angleLimit / 2, hardpoint.up) * hardpoint.forward;
            var projection = Vector3.ProjectOnPlane(target.position - hardpoint.position, hardpoint.up);

            // projection line
            Handles.color = Color.white;
            Handles.DrawDottedLine(target.position, hardpoint.position + projection, dashLineSize);

            // do not draw target indicator when out of angle
            if (Vector3.Angle(hardpoint.forward, projection) > mountPoint.angleLimit / 2) return;

            // target line
            Handles.color = Color.red;
            Handles.DrawLine(hardpoint.position, hardpoint.position + projection);

            // range line
            Handles.color = Color.green;
            Handles.DrawWireArc(hardpoint.position, hardpoint.up, from, mountPoint.angleLimit, projection.magnitude);
            Handles.DrawSolidDisc(hardpoint.position + projection, hardpoint.up, .5f);
#endif
        }
    }

    void Update()
    {
        // do nothing when no target
        if (!target) return;
            
        // aim target
        var aimed = true;
        foreach (var mountPoint in mountPoints)
        {
            if (!mountPoint.Aim(target.position))
            {
                aimed = false;
            }
        }

        // shoot when aimed
        if (aimed)
        {
            gun.Fire();
        }
    }
}