I tried to implement render-to-texture, and it worked out fine! I thought. Now I tried switching the size of the texture and got the wierdest results.
When I make it larger than the viewports size, the rendertarget gets swichted to the backbuffer. I investigated that in PIX, but all I could come up with is that the rendertarget gets switched correctly, but the drawcalls just show black, and when the first drawcall on the backbuffer is made, the things on the texture are already drawn to it.
So, do you have any clue what could be causeing this?