protected virtual void CameraMouseRotate(float dx, float dy) {
var size = 180.0f / Math.Min(Form.Height, Form.Width);
dx *= size;
dy *= size;
Kn5ObjectRenderer.Camera.Pitch(MathF.ToRadians(dy));
Kn5ObjectRenderer.Camera.Yaw(MathF.ToRadians(Kn5ObjectRenderer.UseFpsCamera ? dx : -dx));
Kn5ObjectRenderer.AutoRotate = false;
Renderer.IsDirty = true;
}