public void DrawPower(SpriteBatch spriteBatch, PowerUp a)
{
spriteBatch.Draw(textura, a.Position, sourceRect, Color.White, 0f, origen, 1f, SpriteEffects.None, 0);
}
public void UpdatePower(PowerUp a, float elapsed)
{
a.Position.Y += a.Velocityy * elapsed;
a.Position.X += a.Velocityx * elapsed;
a.boundingBox = new Rectangle((int)a.Position.X, (int)a.Position.Y, textura.Width, textura.Height);
}