More nullable fixes, make SetTransform a part of base Renderer.

TestGame/TestPlayer.cs

@@ -14,7 +14,10 @@ public class TestPlayer : RectangleShape2d
             Current = true,
         };
 
-        Layer.AddEntity(_camera);
+        if (Layer is not null)
+        {
+            Layer.AddEntity(_camera);
+        }
     }
 
     protected override void OnUpdate(double dt)
@@ -27,10 +30,13 @@ 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);
+        if (_camera is not null)
+        {
+            _camera.Position = MathUtils.LerpVector2(_camera.Position, Position, dt * 5f);
+        }
     }
 
     private Logger _logger = new(nameof(TestPlayer));
     private float _speed = 200f;
-    private Camera2d _camera;
+    private Camera2d? _camera;
 }