Direct3D9 cannot access the GPU when minimizing or locking the screen, even without a display monitor hardware. Is here a resolution to let Direct3D9 work even no display monitor is connected with machine. For example, create a software display monitor or hook some logics? I don't know.

Thanks for your help.

I try to convert Direct3D9 to Direct3D9Ex to let it work. But some formats of memory pool are not supported in Direct3D9Ex.

CodePudding user response：

D3D9 normally cannot be run on a "headless" system. That feature is exclusive to modern D3D/DXGI. Unless your application must run on Windows XP or older OSes, it's probably easier to migrate to D3D11 or D3D12 at this point. XP's market share is vanishingly small these days, especially for users wanting to run D3D content (i.e. games).

See this MS Support Article and Microsoft Docs.