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For controlling animation speed, I usually use timeGetTime(). It has fairly low overhead, and a resolution of 1-5 ms.
I only use a high resolution timer (like QueryPerformanceCounter()) for profiling functions in my code.
[This message has been edited by mhkrause (edited December 12, 1999).]
By the way, what's the difference between timeGetTime and GetTickCount?
[This message has been edited by Qoy (edited December 12, 1999).]
Second, why do you think that is high overhead? The way you've set up your loop...your getting the counter ONE each cycle through...and TESTING it inside the loop i assume MANY times...the relitive cost of using HP timers is small compared to the many tests against the returned value. although to keep the INTERNAL code efficient, you should probably convert one of the two functions returns to a format like the other (to prevent users from needing to use the if/else pair).
Finnally, I realize this type of game loop is common, but with WINDOWS (message bsed) and High Performance timers...WHY? The whole point of these timers is to TIME things...to make them run when they are supposed to...instead of AS FAST AS POSSIBLE.... so why run a game loop...AS FAST AS POSSIBLE...polling the time and testing it all over the place for each movement. How about an EVENT DRIVEN system. Our DirectX gambling game (800x600x16bpp running 60FPS) uses the HP TIMER tests in the WinMain function (chaning the layout of the message loop to include it). See, every few times throught the message loop (few can be every one, or every 10) or EVERY time when there is NO message waiting - we call a function to test the high peformance timers we've set up. The function gets the performance count, then tests each timer we've set up, if they are triggered, we post the associated message, and reset the timers time (to the current time). This way...we KNOW that the Move() function is called exactly 100 times a second, and the UpdateDisplay() function is called 60 times a second, etc etc etc...and these do not affect each other (unless they lag of course). But even in lag situations, this system allows you to CHOOSE recovery behavior and implement it in ONE location...do you want to DROP FRAMES???? do you want the computer to KEEP posting message and hope it doesn't crash???? do you want to turn the WHOLE thing off (all timers to keep it in comparitive sync) until the message queue is empty? these are easy in such a system....
well...i might write a gamedev article about this topic...but...until then....GOOD LUCK
But, they don't go into any detail how to use it effectively with
a Windows messaging system, or how/why it should really work.
This is what we all really want to know.
Zip
For not, back to my second question:
What is the difference between GetTickCount() and timeGetTime()?
timeGetTime() has a resolution of 1 ms on Windows 9x and 5 ms on Windows NT.
GetTickCount() has a resolution of 55 ms, or 18 Hz.
So timeGetTime() would be better for your purposes. BTW, this is a "multimedia timer" and you must include mmsystem.h and link with winmm.lib.
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