title: Achieving night effect for 2d game using cocos2d
body: <p>i would like to know if you have any idea how to achieve a night effect without reworking all my images.
  Something exactly like in Tiny Wings for iPhone.
  Tinting the image in cocos2d doesn't do the trick. I guess there might be some combination with opengl blending that might do it, but i haven't had success.</p>
  
  <p>Any ideas?</p>
  
  <p>Thanks!</p>