在 D3D12 上获取显示器的刷新率

Question

我正在将代码从D3D11移植到D3D12，并试图在D3D12上获得显示器的刷新率。我使用刷新率进行精确的动画计时(这是一个硬性要求(。此代码适用于D3D11:

HRESULT GetRefreshRate(IUnknown* device, IDXGISwapChain* swapChain, double* outRefreshRate)
{
Microsoft::WRL::ComPtr<IDXGIOutput> dxgiOutput;
HRESULT hr = swapChain->GetContainingOutput(&dxgiOutput);
if (FAILED(hr))
return hr;
Microsoft::WRL::ComPtr<IDXGIOutput1> dxgiOutput1;
hr = dxgiOutput.As(&dxgiOutput1);
if (FAILED(hr))
return hr;
DXGI_MODE_DESC1 emptyMode = {};
DXGI_MODE_DESC1 modeDescription;
hr = dxgiOutput1->FindClosestMatchingMode1(&emptyMode, &modeDescription, device);
if (SUCCEEDED(hr))
*outRefreshRate = (double)modeDescription.RefreshRate.Numerator / (double)modeDescription.RefreshRate.Denominator;
return hr;
}

不幸的是，ID3D12Device没有实现IDXGIDevice接口，因此FindClosestMatchingMode1失败，并出现以下错误：

DXGI ERROR: IDXGIOutput::FindClosestMatchingMode: pConcernedDevice doesn't support the IDXGIDevice interface [ MISCELLANEOUS ERROR #69: ]

使用D3D12时，是否有获得IDXGIDevice的方法？或者，如何确定D3D12显示器的刷新率？

我知道EnumDisplaySettings，但它返回一个整数，因此缺乏精度，导致动画漂移。我还发现了DwmGetCompositionTimingInfo，但是，它似乎只支持获取主监视器的信息。

我还需要一个同时适用于传统Win32和UWP应用程序的解决方案。如果需要，我愿意为不同的应用程序模型使用两个代码路径。

Answer 1

我们可以使用CCD api获得刷新率，以下是供您参考的代码：

HRESULT GetRefreshRate(IDXGISwapChain* swapChain, double* outRefreshRate)
{
ComPtr<IDXGIOutput> dxgiOutput;
HRESULT hr = swapChain->GetContainingOutput(&dxgiOutput);
// if swap chain get failed to get DXGIoutput then follow the below link get the details from remarks section
//https://learn.microsoft.com/en-us/windows/win32/api/dxgi/nf-dxgi-idxgiswapchain-getcontainingoutput
if (SUCCEEDED(hr))
{
ComPtr<IDXGIOutput1> dxgiOutput1;
hr = dxgiOutput.As(&dxgiOutput1);
if (SUCCEEDED(hr))
{
// get the descriptor for current output
// from which associated mornitor will be fetched
DXGI_OUTPUT_DESC outputDes{};
hr = dxgiOutput->GetDesc(&outputDes);
if (SUCCEEDED(hr))
{
MONITORINFOEXW info;
info.cbSize = sizeof(info);
// get the associated monitor info
if (GetMonitorInfoW(outputDes.Monitor, &info) != 0)
{
// using the CCD get the associated path and display configuration
UINT32 requiredPaths, requiredModes;
if (GetDisplayConfigBufferSizes(QDC_ONLY_ACTIVE_PATHS, &requiredPaths, &requiredModes) == ERROR_SUCCESS)
{
std::vector<DISPLAYCONFIG_PATH_INFO> paths(requiredPaths);
std::vector<DISPLAYCONFIG_MODE_INFO> modes2(requiredModes);
if (QueryDisplayConfig(QDC_ONLY_ACTIVE_PATHS, &requiredPaths, paths.data(), &requiredModes, modes2.data(), nullptr) == ERROR_SUCCESS)
{
// iterate through all the paths until find the exact source to match
for (auto& p : paths) {
DISPLAYCONFIG_SOURCE_DEVICE_NAME sourceName;
sourceName.header.type = DISPLAYCONFIG_DEVICE_INFO_GET_SOURCE_NAME;
sourceName.header.size = sizeof(sourceName);
sourceName.header.adapterId = p.sourceInfo.adapterId;
sourceName.header.id = p.sourceInfo.id;
if (DisplayConfigGetDeviceInfo(&sourceName.header) == ERROR_SUCCESS)
{
// find the matched device which is associated with current device 
// there may be the possibility that display may be duplicated and windows may be one of them in such scenario
// there may be two callback because source is same target will be different
// as window is on both the display so either selecting either one is ok
if (wcscmp(info.szDevice, sourceName.viewGdiDeviceName) == 0) {
// get the refresh rate
UINT numerator = p.targetInfo.refreshRate.Numerator;
UINT denominator = p.targetInfo.refreshRate.Denominator;
double refrate = (double)numerator / (double)denominator;
*outRefreshRate = refrate;
break;
}
}
}
}
else
{
hr = E_FAIL;
}
}
else
{
hr = E_FAIL;
}
}
}
}
}
return hr;

}

更多关于CCD API的详细信息，您可以参考以下链接：

https://learn.microsoft.com/en-us/windows-hardware/drivers/display/ccd-apis