Voile/TestGame/TestPlayer.cs

using Voile;
using Voile.Extensions;
using Voile.SceneGraph;
using Voile.Utils;

public class TestPlayer : RectangleShape2d
{
    public float SprintSpeed { get; set; } = 400f;
    protected override void OnStart()
    {
        base.OnStart();
        Color = Color.Cyan;

        _camera = new Camera2d()
        {
            Current = true,
        };

        if (Layer is not null)
        {
            Layer.AddEntity(_camera);
        }
    }

    protected override void OnUpdate(double dt)
    {
        base.OnUpdate(dt);

        var sprinting = Input.IsActionDown("sprint");
        _speed = sprinting ? SprintSpeed : 200f;

        var velocity = Input.GetInputDirection("left", "right", "up", "down") * _speed;
        Position += velocity * (float)dt;

        if (_camera is not null)
        {
            _camera.Position = _camera.Position.Lerp(Position, dt * 5f);
        }
    }

    private Logger _logger = new(nameof(TestPlayer));
    private float _speed = 200f;
    private Camera2d? _camera;
}