private void MainWindow_Resize(object sender, EventArgs e)
{
GL.Viewport(0, 0, ClientSize.Width, ClientSize.Height);
_projectionMatrix = Matrix4.CreatePerspectiveFieldOfView(MathE.ToRad(45), ClientSize.Width / (float)ClientSize.Height, 0.1f, 100);
_viewMatrix = Matrix4.LookAt(_camera, _target, new Vector3(0, 1, 0));
}