Can I use std::chrone::high_resolution_clock to get the time to calculate my fixed time step?
Or should I use the platform specific functions like QueryPerformanceCounter ?
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#4 Members - Reputation: 315
Posted 07 December 2012 - 06:54 PM
Microsoft didn't use their performance counter in implementing C++11's high resolution clock. As a result it's not really high resolution and is probably an order of magnitude or so low for your frame timer. (See the bug report. They intend to roll out a fix in their next release.)
You can test a clock's resolution by getting a time from it repeatedly until it returns a different time. Then you can decide for yourself if its resolution is sufficient for your purpose.
You can test a clock's resolution by getting a time from it repeatedly until it returns a different time. Then you can decide for yourself if its resolution is sufficient for your purpose.
#5 Members - Reputation: 2907
Posted 07 December 2012 - 08:07 PM
VReality, good to know. Microsoft just released (or maybe will soon) the first VS2012 update, so it might have been fixed already. I'll see if I can confirm that.
If not, in the meantime, OP can use QuerryPerformanceCounter, or boost::chrono, which uses QPC on Windows, as a work-around.
If not, in the meantime, OP can use QuerryPerformanceCounter, or boost::chrono, which uses QPC on Windows, as a work-around.
#6 Members - Reputation: 2907
Posted 07 December 2012 - 08:07 PM
VReality, good to know. Microsoft just released (or maybe will soon) the first VS2012 update, so it might have been fixed already. I'll see if I can confirm that.
If not, in the meantime, OP can use QuerryPerformanceCounter, or boost::chrono, which uses QPC on Windows, as a work-around.
If not, in the meantime, OP can use QuerryPerformanceCounter, or boost::chrono, which uses QPC on Windows, as a work-around.
#7 Members - Reputation: 289
Posted 08 December 2012 - 12:54 AM
In the event VS2012 actually supports std::chrono, here is a timer class that uses it. http://codepad.org/vVVA7qLC
#8 Members - Reputation: 1336
Posted 08 December 2012 - 01:02 AM
I'd definitely go with boost::chrono, since in theory once VS2012 has a working implementation it should be a simply matter of replacing boost with std.
Bit of frustrating, when I wanted to see how high-res that clock is and realized that all the clocks have the same resolution. Feels like one of this situation like "marketing wants to check off on that feature, so screw it if it works or not, just put something in there and let people file a bug report about it".
Bit of frustrating, when I wanted to see how high-res that clock is and realized that all the clocks have the same resolution. Feels like one of this situation like "marketing wants to check off on that feature, so screw it if it works or not, just put something in there and let people file a bug report about it".
f@dzhttp://festini.device-zero.de
#10 Members - Reputation: 315
Posted 08 December 2012 - 07:57 AM
In the event VS2012 actually supports std::chrono, here is a timer class that uses it. http://codepad.org/vVVA7qLC
Just to be clear, VS2012 does provide the full std::chrono library.
However, the standard library is implemented individually on each platform. And VS2012 came with an implementation in which the high resolution clock is not really high resolution (has far less resolution than the performance counter provided by the hardware/OS).
Again, they have expressed the intention to fix this in the "out of band" release before the next version of VS.
