Irrlicht Engine

Subj.

For example i start render i made picture, that i want to show.
How can i modify this picture? And how can i get access to this picture?

you can directly access a texture if you call

video::ITexture* i = driver->getTexture(...);
void* buffer = i->lock();

I know this

I mean...
I want get access to image, that renderer draw before showing it.
I want modify this image and apply some effects on it.

I'm not very common with these advanced game effects, but I thing most of them are done with pixel and vertex shaders

Um-m-m-m-m-m. :-E~
SHADERS!
I hate them!