/// <summary>
/// when the angle is changed on the form the current tanks aim is changed
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void angleUpDown_ValueChanged(object sender, EventArgs e)
{
currentTank.Aim((float)angleUpDown.Value);
// update the tank graphics to match the angle of the barrel of tank
DrawGameplay();
//refresh the screen
displayPanel.Invalidate();
currentTank.Paint(gameplayGraphics.Graphics, displayPanel.Size);
}