Direct3D 對暫停與繼續的支援

#include <appnotify.h>

PAPPSTATE_REGISTRATION hPLM = {};
HANDLE plmSuspendComplete = nullptr;
HANDLE plmSignalResume = nullptr;

// Create a window.

plmSuspendComplete = CreateEventEx(nullptr, nullptr, 0, EVENT_MODIFY_STATE | SYNCHRONIZE);
plmSignalResume = CreateEventEx(nullptr, nullptr, 0, EVENT_MODIFY_STATE | SYNCHRONIZE);
if (!plmSuspendComplete || !plmSignalResume)
    return 1;

if (RegisterAppStateChangeNotification([](BOOLEAN quiesced, PVOID context)
{
    if (quiesced)
    {
        ResetEvent(plmSuspendComplete);
        ResetEvent(plmSignalResume);

        // To ensure we use the main UI thread to process the notification, we self-post a message.
        PostMessage(reinterpret_cast<HWND>(context), WM_USER, 0, 0);

        // To defer suspension, we must wait to exit this callback.
        (void)WaitForSingleObject(plmSuspendComplete, INFINITE);
    }
    else
    {
        SetEvent(plmSignalResume);
    }
}, hwnd, &hPLM))
    return 1;

// Message loop

UnregisterAppStateChangeNotification(hPLM);

CloseHandle(plmSuspendComplete);
CloseHandle(plmSignalResume);

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
...
    switch (message)
    {
    case WM_USER:
        // Notify any threads using other command queues to halt operations and wait for acknowledgement.

        // Call SuspendX(0) on the graphics command queue, and cease all GPU submissions. This API is asynchronous so
        // that the game can continue doing work below.
        pGraphicsQueue->SuspendX(0);

        // Complete deferral.
        SetEvent(plmSuspendComplete);

        (void)WaitForSingleObject(plmSignalResume, INFINITE);

        // Before picking up rendering again, call ResumeX on the graphics command queue.
        pGraphicsQueue->ResumeX();

        // Notify any threads using other command queues that it's safe to resume operations.

        // Register again for frame events via SetFrameIntervalX and ScheduleFrameEventX.
        break;
    }