问题描述
我想编写一个基本记录DWM组合速率的工具，以便我可以检测外部应用程序中的渲染延迟。像fraps这样的工具可以实现这样的功能，所以我知道这可能是某种方式。由于我在窗口模式下运行，因此DwmGetCompositionTimingInfo
看起来就像我需要的确切功能。但是，它的行为似乎与MSDN文档不匹配。根据我的理解，此代码段应该有效：
I'd like to write a tool that basically logs the DWM's composition rate so I can detect rendering lag in external applications. Tools like fraps accomplish such functionality, so I know this is possible somehow. Since I am running in windowed mode, DwmGetCompositionTimingInfo seems like the exact function I need. However, its behavior does not appear to match the MSDN documentation. From what I understand, this code snippet should work:
void main（）
{
std :: uint64_t dwm_frames_rendered（0）;
std :: uint64_t dwm_frames_skipped（0）;
for（size_t interval_count（0）; interval_count< 500; ++ interval_count）
{
DWM_TIMING_INFO initial_timing_info {};
initial_timing_info.cbSize = sizeof（initial_timing_info）;
DwmGetCompositionTimingInfo（NULL，& initial_timing_info）;
DWM_TIMING_INFO current_timing_info {};
current_timing_info.cbSize = sizeof（current_timing_info）;
do
{
DwmGetCompositionTimingInfo（NULL，& current_timing_info）;
} while（initial_timing_info.qpcVBlank == current_timing_info.qpcVBlank）;
if（initial_timing_info.cFrameConfirmed！= current_timing_info.cFrameConfirmed）
{
++ dwm_frames_rendered;
}
其他
{
++ dwm_frames_skipped;
}
}
std :: cout<< "渲染的帧：" << dwm_frames_rendered<< std :: endl
<< "跳过框架：" << dwm_frames_skipped<<的std :: ENDL;
}
void main (){ std::uint64_t dwm_frames_rendered (0); std::uint64_t dwm_frames_skipped (0); for (size_t interval_count (0); interval_count < 500; ++interval_count) { DWM_TIMING_INFO initial_timing_info {}; initial_timing_info.cbSize = sizeof (initial_timing_info); DwmGetCompositionTimingInfo (NULL, &initial_timing_info); DWM_TIMING_INFO current_timing_info {}; current_timing_info.cbSize = sizeof (current_timing_info); do { DwmGetCompositionTimingInfo (NULL, ¤t_timing_info); } while (initial_timing_info.qpcVBlank == current_timing_info.qpcVBlank); if (initial_timing_info.cFrameConfirmed != current_timing_info.cFrameConfirmed) { ++dwm_frames_rendered; } else { ++dwm_frames_skipped; } } std::cout << "Frames rendered: " << dwm_frames_rendered << std::endl << "Frames skipped: " << dwm_frames_skipped << std::endl;}
但是，dwm_frames_skipped永远不会增加。使用调试器逐步执行它，看起来每次调用DwmGetCompositionTimingInfo时，无论何时调用它们，以下值都会增加1。你可以注入
睡眠，立即打电话等等，所有DwmGetCompositionTimingInfo似乎都会返回一个稳定增加1的值：
But instead, dwm_frames_skipped never gets incremented. Stepping through it with the debugger, it appears that every time that DwmGetCompositionTimingInfo is called, the following values get incremented by 1 regardless of when they are invoked. You can inject sleeps, call immediately, etc., and all DwmGetCompositionTimingInfo appears to do is return a steady incremented by 1 value for:
- cRefresh
- cDXRefresh
- C框架
- cDXPresent
- cRefreshFrame
- cFrameSubmitted
- cFrameConfirmed
- cDXPresentConfirmed
- cRefreshConfirmed
有没有人对究竟出了什么问题有任何想法？
Does anyone have any ideas on what exactly is going wrong?
谢谢，
Jason Stern
Jason Stern
推荐答案
感谢您在此发帖。
我已经测试了你的代码，在成功工作之前，我应该配置添加Dwmapi.lib库的属性页面。
I have tested you code, before working successfully, I should configure the property page adding Dwmapi.lib library.
看我的屏幕截图：
根据测试结果，dwm_frames_skipped变量始终为零。我认为这主要是因为。
According to test result, the dwm_frames_skipped variable always is zero. I think that this is mainly reason.
cFrameConfirmed上次确认为呈现的DWM帧号。
cFrameConfirmed The DWM frame number that was last confirmed as presented.
我认为我们无法比较一个程序中的值，因为现在总是在变化。
I think that we cannot compare the value inside one program, because the present is always changing.
最好的问候，
Hart
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