I'm porting my 2D game engine from SDL/OpenGl to DirectX 9.0c. I need to be able to create bitmaps and blit stuff on them, so I figure I need to render to a surface. I'm using the ID3DXRenderToSurface interface to handle the details about rendering. Problem is, this is VERY slow. I suppose it happens because my texture does not have D3DUSAGE_RENDERTARGET specified so the interface has to render to its internal texture, then copy to my texture. So I try putting the render target flag, but now it complains that it is not in the default pool, and that's not exactly better because that would mean that I have to re-render everything when my device is lost, and I might need to lock too. (But it fixes the speed problem if I put default.) There's also another problem with rendering to a surface: the parts where nothing was rendered on gets garbage like what was previously on the screen the last time I ran the engine. I doubt I'm the first one trying to do a simple 2D engine with DirectX 9.0c, so how is this usually done?

Anyone? I'm sorta blocked on that issue.