How do I open a hardware accelarated DirectX window on a secondary screen

I'm looking to create a hardware accelarated DirectX (9 at the moment) window on a secondary screen. This screen is connected to the same graphics display as the primary screen (at least at the moment).

Currently, when I try to open the window on the secondary screen based on window position or by dragging it there, CPU usage jumps by about 10%, which seems to indicate that windows is switching to a software fallback rather than the hardware accelaration.

Machine is wind开发者_StackOverflowows XP running a NVIDIA graphics card (varying cards as this runs on several machines), with the latest driver. It's also running CUDA at the same time to produce the images if that matters. Programming language is c++, manual window and message queue creation, no tookbox used at the moment to manage the GUI

Thanks

When you call CreateDevice, make sure to use the index of the monitor you are targeting. The standard D3DADAPTER_DEFAULT value is just 0, which is the primary monitor. DirectX is a bit kludgy that way, but if the window is on a different monitor than is specified in CreateDevice, then it will silently render in a framebuffer targeting the first monitor, then buffer copy to a framebuffer on the second monitor using the OS window manager.

So, the quick and dirty solution is to use CreateDevice(1, ...) instead since that is almost always be how a dual monitor setup is indexed.

A more robust solution is to use MonitorFromWindow(hwnd) to find the monitor that the window covers the most, then iterate through available d3d adapters looking for one that returns the same monitor handle using GetAdapterMonitor(). If you have a system with more than two monitors, or if you don't know in advance what monitor you want and just have an HWND, then you need the longer method.