// used by UI to choose human player turn
public void TogglePlayerColor()
{
playerGoesFirst = !playerGoesFirst;
if (playerGoesFirst)
{
Black.SetHuman();
White.SetComputer();
ui.SetPlayerColorImage(Color.black);
}
else
{
Black.SetComputer();
White.SetHuman();
ui.SetPlayerColorImage(Color.white);
}
}