问 如何在我的OpenGL应用程序中实现精确的(但可变的) FPS限制/上限？

我建议使用子毫秒精度系统定时器(QueryPerformanceCounter，gettimeofday)来获取定时数据。这些也可以帮助您分析优化版本构建中的性能。

我建议你使用SDL。我个人用它来管理我的计时器。此外，它还可以使用SDL1.3将fps限制在屏幕刷新速率(V)上。这使您能够限制CPU的使用，同时拥有最好的屏幕性能(即使您有更多的帧，它们也无法显示，因为屏幕刷新不够快)。

功能是

SDL_GL_SetSwapInterval(1)；

如果您想要一些使用SDL的定时器代码，您可以在这里看到：

我的计时器课

祝你好运:)

我认为实现这个目标的一个好方法，无论你使用什么样的图形库，都是在游戏中有一个时钟测量，以考虑到每一个滴答(ms)。这样，平均fps就会和半衰期2中的限制完全一样。希望下面的代码片段能够解释我说的内容：

//FPS limit
unsigned int FPS = 120;
//double holding clocktime on last measurement
double clock = 0;
while (cont) {
    //double holding difference between clocktimes
    double deltaticks;
    //double holding the clocktime in this new frame
    double newclock;
    //do stuff, update stuff, render stuff...
    //measure clocktime of this frame
    //this function can be replaced by any function returning the time in ms
    //for example clock() from <time.h>
    newclock = SDL_GetTicks();
    //calculate clockticks missing until the next loop should be
    //done to achieve an avg framerate of FPS 
    // 1000 / 120 makes 8.333... ticks per frame
    deltaticks = 1000 / FPS - (newclock - clock);
    /* if there is an integral number of ticks missing then wait the
    remaining time
    SDL_Delay takes an integer of ms to delay the program like most delay
    functions do and can be replaced by any delay function */
    if (floor(deltaticks) > 0)
        SDL_Delay(deltaticks);
    //the clock measurement is now shifted forward in time by the amount
    //SDL_Delay waited and the fractional part that was not considered yet
    //aka deltaticks
    the fractional part is considered in the next frame
    if (deltaticks < -30) {
        /*dont try to compensate more than 30ms(a few frames) behind the
        framerate
        //when the limit is higher than the possible avg fps deltaticks
        would keep sinking without this 30ms limitation
        this ensures the fps even if the real possible fps is
        macroscopically inconsitent.*/
        clock = newclock - 30;
    } else {
        clock = newclock + deltaticks;
    /* deltaticks can be negative when a frame took longer than it should
    have or the measured time the frame took was zero
    the next frame then won't be delayed by so long to compensate for the
    previous frame taking longer. */
    //do some more stuff, swap buffers for example:
    SDL_RendererPresent(renderer); //this is SDLs swap buffers function
}

我希望这个带有SDL的例子有所帮助。每帧只测量一次时间是很重要的，因此每一帧都被考虑在内。我建议在一个使您的代码更清晰的函数中模块化这个定时。这段代码在最后一段中没有注释，它们只是让您感到厌烦：

unsigned int FPS = 120;
void renderPresent(SDL_Renderer * renderer) {
    static double clock = 0;
    double deltaticks;
    double newclock = SDL_GetTicks();
    deltaticks = 1000.0 / FPS - (newclock - clock);
    if (floor(deltaticks) > 0)
        SDL_Delay(deltaticks);
    if (deltaticks < -30) {
        clock = newclock - 30;