How to limit the FPS independently from the screen refresh?

[Devil Master]

I want to make sure that a program I'm making runs at 60 FPS max on every computer, independently from the speed of the above-mentioned computers and, more important, independently from the screen refresh rate that has been set in the video card options.
I know that I can just enable vsync and everything will be capped at the selected refresh rate, but the problem here is that the speed of the program will change if the refresh rate is changed. So, how do I tell the main loop to pause if the current frame took less than 1/60 of a second to render?
The only explicit reference to an FPS limiter I found was made by some guy who either erased his account or was banned, so I can't ask him for a link to his FPS limiter.

[Bear_130278]

Code: Select all

	if(irrtime-lasttime>=16.6f)
		{
		lasttime=irrtime;
		driver->beginScene(true, true, video::SColor(0,0,0,0));
                Draw All;
		driver->endScene();
		}

Like this *)

And ofcourse, this will work IF your scene renders FASTER or EQUAL to 60FPS... Otherwise, you'll get the real FPS )

[m_krzywy]

Code: Select all

	if(irrtime-lasttime>=16.6f)
		{
		lasttime=irrtime;
		driver->beginScene(true, true, video::SColor(0,0,0,0));
                Draw All;
		driver->endScene();
		}

Like this *)

And ofcourse, this will work IF your scene renders FASTER or EQUAL to 60FPS... Otherwise, you'll get the real FPS )

What type is irrtime and lasttime?

[t0rt0r0]

Guess f32

[hybrid]

Better make your program framerate independent, the wait solutions are always approximative, because it won't handle changing system load well, and the usual precision errors wil also lead to some differences. Moreover, irrtime and lasttime should be u32 (in milliseconds), don't know why the comparison uses floats.

[Devil Master]

Bear_130278: thanks for the code. Only... if irrtime is not a system variable (the only reference to "irrtime irrlicht" I found on Google is this thread), how is it updated?

hybrid: I don't want just a way to limit the speed of the program, I also want to make sure that my program works correctly and does not go off sync in stereoscopic 3D, which is generally based on switching from the left-eye view to the right-eye view or viceversa 60 times a second (in the case of HMDs like the Z800), or 120 times a second (in the case of shutterglasses like the nVidia 3D Vision set).

EDIT: I tried to initialize irrtime like this:
irrtime=device->getTimer()->getTime();
just before the condition posted by Bear_130278. The result is that everything happens so fast that I literally have no control over it. Why?

EDIT 2: I got it. The whole game loop, and not just the rendering part of it, must be enclosed within the condition.

[hybrid]

The glasses will force a vsync of the necessary rate, so just enable vsync and it works. I do use such glasses

[Bear_130278]

The code i posted was a kind of pseudocode )))
Thus....
irrtime is irrtime=device->getTimer()->getTime(); That is correct...
lasttime is u32

The result is that everything happens so fast that I literally have no control over it. Why?
You answered by yourself.... *))

And of course hybrid is right, and this solution is not very accurate....
But, if you are 100% sure that ALL the calculations and rendering will take less than 1\60 second then you'll get pretty predictable result.