Rendering To Texture

There is info on about how to render fast to a texture in dx7… but how on opengl? i got it working, but its not so fast…

i use glReadPixels with GL_RGB and GL_UNSIGNED_BYTE

and then glTexSubImage with the same parameters (no! )

pixelalignemends are set to 1… pack and unpack (or whatever)

what can i do with pixeltransfer and these?

ok, i found glCopyTexSubImage, but its slow anyways…