Thread: Setting the BackBuffer

Hi, I've been searching how to change the main Back Buffer and unfortunatelly didn't find anything helpful. Basicly I need to change the main pointer to a BackBuffer to a pointer of a surface compatible with the back buffer format. The idea is to get some frames from the main stream and anylyze data in them without using lock methods that are lowing the performance.

So I will:

1.Switch pointers of BackBuffer and my surface.
2.Anylyze data in BackBuffer.
3.Wait 0.5s
4.Switch back the pointers.
5.Analyze data in my surface.
6.Wait 0.5s
7.Switch pointers of BackBuffer and my surface.
8.Anylyze data in BackBuffer.
...

I need only to point me. And maybe also some suggestions about setting my surface format compatible with BackBuffer format. I'm writing my code in C++, DirectX 9.

Nevermind. I will set the render target(the default one is Back Buffer). But Does the GetBackBuffer(UINT iSwapChain,UINT BackBuffer, D3DBACKBUFFER_TYPE Type, IDirect3DSurface9 ** ppBackBuffer) method returns only the pointer to Back Buffer or it copyies a whole surface? And when I'm accessing the surface that GetBackBuffer method returned me do I have any possibility to avoid locking the surface?(In fact I don't know how the mechanism of locking surface works). What will happen If I don't lock the surface? The compilator threats this like a mistake?

Thanks for reply. Could you throw some functions names with which I could do that(pre-caching the pointer and getting pixels from an input texture in shader)?

No but you can do some research in the SDK and books and figure it out.