Fix MathUtils.LerpVector2, add cameras.

TestGame/TestPlayer.cs

@@ -8,6 +8,14 @@ public class TestPlayer : RectangleShape2d
     {
         base.OnStart();
         Color = Color.Cyan;
+        _logger.Echo("OnStart");
+
+        _camera = new Camera2d()
+        {
+            Current = true,
+        };
+
+        Layer.AddEntity(_camera);
     }
 
     protected override void OnUpdate(double dt)
@@ -19,7 +27,11 @@ public class TestPlayer : RectangleShape2d
 
         var velocity = Input.GetInputDirection("left", "right", "up", "down") * _speed;
         Position += velocity * (float)dt;
+
+        _camera.Position = MathUtils.LerpVector2(_camera.Position, Position, dt * 5f);
     }
 
+    private Logger _logger = new(nameof(TestPlayer));
     private float _speed = 200f;
+    private Camera2d _camera;
 }