public override void Update(GameTime gameTime, Rectangle viewportRect)
{
Vector2 difference;
//difference between positions
difference.X = food.getPos().X - screenPos.X;
difference.Y = food.getPos().Y - screenPos.Y;
// Get the direction that the shark needs to go in.
difference.Normalize();
// Move the shark
screenPos = screenPos + Velocity * difference * (float)gameTime.ElapsedGameTime.TotalSeconds;
}
