gather-and-defend/Assets/Scripts/Projectile.cs

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

public class Projectile : MonoBehaviour
{

    [SerializeField]
    private Detection _detectionLinked;

    [SerializeField]
    private bool straightProjectile = false;

    private float _time = 0f;
    private float _duration = 1f;

    [SerializeField]
    private float _angle = 10f; //Default
    [SerializeField]
    private float _speed = 2f; //Default

    private Vector2 _vectorStart;
    private Vector2 _vectorEnd;
    
    private int _damage;
    private float _enemySpeed;
    private Entity _target;

    private Rigidbody2D _rigidbodyProjectile;
    private float _initialX;
    private float _initialY;
    private float _destinationX;
    private float _destinationY;
    private float _enemyPosY = 0f;
    private float _speedTime = 0f;

    private float _initialXDistance;
    private float _initialYDistance;

    private void Start() 
    {
        _rigidbodyProjectile = GetComponent<Rigidbody2D>();
        _initialX = transform.position.x;
        _initialY = transform.position.y;
        _destinationX = _vectorEnd.x - _initialX - _enemySpeed;
        _destinationY = _vectorEnd.y - _initialY;
        
        _detectionLinked.gameObject.GetComponent<Detection>().EntityLinked = _target;
        _detectionLinked.gameObject.GetComponent<Detection>().ProjectileDamage = _damage;

        _initialXDistance = Mathf.Abs(_initialX - _destinationX);
        _initialYDistance = Mathf.Abs(_initialY - _destinationY);
    }

    private void Update()
    {
        if (straightProjectile)
        {

            transform.position = Vector2.Lerp(new Vector2(_initialX, _initialY), 
                new Vector2(_vectorEnd.x, _vectorEnd.y), _time/_duration);

            DetStraigthArrowAngle();

            //TODO: Implementer cette methode pour mieux faire fonctionner le projectile lorsque possible.
            //transform.LookAt(VectorEnd, Vector3.forward);

            _time += Time.deltaTime;

            if (transform.position.x >= _vectorEnd.x)
            {
                Destroy(this.gameObject);
            }
            return;
        }

        float x = _speedTime;
        float y = x >= 0 ? (_angle*-Mathf.Pow(x, 2) + _destinationX * x) : - (_angle * -Mathf.Pow(x, 2) + _destinationX * x); 

        transform.position = new Vector2(_initialX + x*_angle, _initialY + y);

        // Move projectile angle according to distance with target
        float lerpStep = (_destinationX - transform.position.x) / _initialXDistance;
        float angle = Mathf.Lerp(-100f, 45f, lerpStep);
        transform.eulerAngles = new Vector3(0, 0, angle);

        _speedTime += _speed * Time.deltaTime;

        if(y < 0) {
            Destroy(this.gameObject);
        }
    }

    private void DetStraigthArrowAngle()
    {

        if(_target != null) _enemyPosY = _target.Position.y;

        float angleX = (_destinationX) / _initialXDistance;
        float angleY = (_destinationY) / _initialYDistance;
        
        //Obtenir difference entre la position Y du chateau et de l'enemie.
        float diffY = transform.position.y - _enemyPosY;

        //Debug.Log("Angle X: " + angleX);

        if (diffY >= 0.1 || diffY <= -0.1)
        {
            //TODO: L'angle fonctionne mieux, mais il y a toujours des problemes avec les angles pret de X
            //ou ils sont beaucoup trop verticaux.
            //L'angle a l'air de fonctionner lorsqu'il tire en avant (X positif), mais on dirait qu'il y a un probleme
            //lorsque X est negatif.
            //TODO: Recalculer la vitesse pour qu'elle fonctionne lorsque le projectile est tire en arriere.
            float lerpStepS;
            if (angleX > 0.23) lerpStepS = Mathf.Rad2Deg * Mathf.Atan(angleX / angleY);

            else if (angleX >= 0) lerpStepS = Mathf.Rad2Deg * Mathf.Atan(angleY / angleX);

            else { 

                lerpStepS = -Mathf.Rad2Deg * Mathf.Atan(angleY / angleX);
            } 
            
            float angleS = Mathf.Lerp(lerpStepS, 0, 0);
            transform.eulerAngles = new Vector3(0, 0, angleS);
        }
    }

    //Getter and Setter
    public float EnemySpeed
    {
        get { return _enemySpeed; }
        set { _enemySpeed = value; }
    }

    public float Angle
    {
        get { return _angle; }
        set { _angle = value; }
    }

    public float Speed
    {
        get { return _speed; }
        set { _speed = value; }
    }

    public int Damage
    {
        get { return _damage; }
        set { _damage = value; }
    }

    public Vector2 VectorStart
    {
        get { return _vectorStart; }
        set { _vectorStart = value; }
    }

    public Vector2 VectorEnd
    {
        get { return _vectorEnd; }
        set { _vectorEnd = value; }
    }

    public Entity Target
    {
        get { return _target; }
        set { _target = value; }
    }
}