RogueTank/Scripts/World/Pickup.cs

using Godot;
using RogueTank.Actors;
using RogueTank.Util;

namespace RogueTank.World;

public partial class Pickup : Area2D
{
    public enum PickupType
    {
        Coin,
        Xp,
        Heal
    }

    [Export] public PickupType Type { get; set; } = PickupType.Xp;
    [Export] public int Amount { get; set; } = 1;

    private Sprite2D _sprite = null!;
    private Node2D? _magnetTarget;
    private float _magnetSpeed = 0f;

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

        _sprite = new Sprite2D
        {
            Centered = true,
            TextureFilter = CanvasItem.TextureFilterEnum.Nearest
        };
        _sprite.Texture = Type switch
        {
            PickupType.Coin => PixelArt.MakePickupTexture(10, new Color(1f, 0.85f, 0.2f)),
            PickupType.Xp => PixelArt.MakePickupTexture(10, new Color(0.2f, 0.85f, 1f)),
            PickupType.Heal => PixelArt.MakePickupTexture(10, new Color(0.35f, 1f, 0.45f)),
            _ => PixelArt.MakePickupTexture(10, Colors.White)
        };
        AddChild(_sprite);

        var col = new CollisionShape2D { Shape = new CircleShape2D { Radius = 6f } };
        AddChild(col);
    }

    public override void _PhysicsProcess(double delta)
    {
        if (_magnetTarget == null || !IsInstanceValid(_magnetTarget))
            return;

        _magnetSpeed = Mathf.Min(520f, _magnetSpeed + 1400f * (float)delta);
        var dir = (_magnetTarget.GlobalPosition - GlobalPosition).Normalized();
        GlobalPosition += dir * _magnetSpeed * (float)delta;
    }

    private void OnAreaEntered(Area2D area)
    {
        // Magnet area: start homing when enter.
        if (area.GetParent() is PlayerTank p && area == p.GetMagnetArea())
        {
            _magnetTarget = p;
            return;
        }
    }

    private void OnBodyEntered(Node body)
    {
        if (body is not PlayerTank p) return;

        switch (Type)
        {
            case PickupType.Coin:
                p.AddCoins(Amount);
                break;
            case PickupType.Xp:
                p.AddXp(Amount);
                break;
            case PickupType.Heal:
                p.Heal(Amount);
                break;
        }

        QueueFree();
    }
}