You need to hook into game process, but it's nothing too hard. Either patching game binary in right place to funnel pointer to needed buffers to your DLL, or ho

You need to hook into game process, but it's nothing too hard. Either patching game binary in right place to funnel pointer to needed buffers to your DLL, or hooking something like D3D11 OMSetRenderTargets and doing some clever guessing which one of buffers this is. Doing this at driver side wouldn't make any difference, as driver doesn't have any extra semantic info what the buffer is used for anyway.