Achieving night effect for 2d game using cocos2d

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 coc开发者_运维百科os2d 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.

Any ideas?

Thanks!

I ended up placing a blue layer on top and using a multiply effect on it. the blend func is: {GL_DST_COLOR, GL_SRC_COLOR} Here is a blog entry I wrote explaining the process: PlaySnack Blog - Achieving a night effect in Cocos2d.