RogueTank/Scripts/Combat/Bullet.cs

using Godot;

namespace RogueTank.Combat;

public partial class Bullet : Area2D
{
    [Export] public float Speed = 520f;
    [Export] public float Damage = 10f;
    [Export] public int Pierce = 0;
    [Export] public float Lifetime = 1.6f;

    private float _alive;
    private Vector2 _velocity;

    public void Init(Vector2 dir)
    {
        _velocity = dir.Normalized() * Speed;
        Rotation = _velocity.Angle();
    }

    public override void _Ready()
    {
        BodyEntered += OnBodyEntered;
        AreaEntered += OnAreaEntered;
    }

    public override void _PhysicsProcess(double delta)
    {
        var d = (float)delta;
        GlobalPosition += _velocity * d;
        _alive += d;
        if (_alive >= Lifetime)
            QueueFree();
    }

    private void OnBodyEntered(Node body)
    {
        if (body is IDamageable dmg)
        {
            dmg.TakeDamage(Damage);
            if (Pierce <= 0)
                QueueFree();
            else
                Pierce--;
        }
        else if (body is StaticBody2D)
        {
            QueueFree();
        }
    }

    private void OnAreaEntered(Area2D area)
    {
        // In case targets use Area2D-based hurtboxes.
        if (area is IDamageableArea dmg)
        {
            dmg.TakeDamage(Damage);
            if (Pierce <= 0)
                QueueFree();
            else
                Pierce--;
        }
    }
}