我正在编写一个简单的Direct3D 12应用程序，为Vulkan发布做准备，在所有方面都符合预期，但有一个问题：在带边框的窗口中运行会将帧率限制在60fps，即使禁用了垂直同步。令我困惑的是：在全屏窗口中运行同一程序时，帧率接近于4000fps。
通过使用自制简陋的性能分析器，我发现问题出现在我的代码的这个部分，该部分等待上一帧完成后才开始处理下一帧。
if (m_fence->GetCompletedValue() < endFenceValue)
{
result = m_fence->SetEventOnCompletion(endFenceValue, m_fenceEvent);
if (result != S_OK) return false;
WaitForSingleObject(m_fenceEvent, INFINITE); //Program stalls here
}
//m_fence is a pointer to an ID3D12Fence object
//endFenceValue is an unsigned long long
//m_fenceEvent is a HANDLE
呈现渲染帧所使用的代码很普通：
if (m_vsync)
{
result = m_swapChain->Present(1, 0);
if (result != S_OK) return 0;
}
else
{
result = m_swapChain->Present(0, 0);
if (result != S_OK) return 0;
}
//Increase the fence value
result = m_commandQueue->Signal(m_fence, m_fenceValue);
if (result != S_OK) return 0;
return m_fenceValue++;
//m_swapChain is a pointer to an IDXGISwapChain3 object
//m_commandQueue is a pointer to an ID3D12CommandQueue object
//m_fenceValue is a HANDLE
注意：第一个代码块使用上面函数的返回值作为
endFenceValue。我正在使用的交换链设置如下：
swapChainDesc.BufferCount = 2; //Double buffered
swapChainDesc.BufferDesc.Width = width; //Set width
swapChainDesc.BufferDesc.Height = height; //Set height
swapChainDesc.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM; //32-bit back buffers
swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT; //Set the back buffers to be used as render targets
swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_DISCARD; //Throw out old back buffer contents after getting a new frame
swapChainDesc.OutputWindow = window;
swapChainDesc.Windowed = !fullscreen;
//Auto-detect the refresh rate
swapChainDesc.BufferDesc.RefreshRate.Numerator = 0;
swapChainDesc.BufferDesc.RefreshRate.Denominator = 0;
//No multisampling for now
swapChainDesc.SampleDesc.Count = 1;
swapChainDesc.SampleDesc.Quality = 0;
//Set the scan line ordering and scaling to unspecified
swapChainDesc.BufferDesc.ScanlineOrdering = DXGI_MODE_SCANLINE_ORDER_UNSPECIFIED;
swapChainDesc.BufferDesc.Scaling = DXGI_MODE_SCALING_UNSPECIFIED;
//Allow to switch between windowed and fullscreen modes
//Also changes the monitor resolution to match the width and height of the window in fullscreen mode
swapChainDesc.Flags = DXGI_SWAP_CHAIN_FLAG_ALLOW_MODE_SWITCH;
对于那些感兴趣的人，我正在使用SDL创建窗口，但编写自己的WinMain并没有解决问题。我还尝试检查nVidia控制面板中的垂直同步设置，退出fl.ux（但不卸载它）以及更改系统属性中的性能设置。
有人可以为此提供解释或解决方案吗？