esuo1198_TaikoArcadeLoader/src/patches/fpslimiter.cpp

#include "helpers.h"
#include "patches.h"

namespace patches::FpsLimiter {

/*
 * Reference: https://github.com/teknogods/OpenParrot/blob/master/OpenParrot/src/Functions/FpsLimiter.cpp
 */

static LARGE_INTEGER PerformanceCount1;
static LARGE_INTEGER PerformanceCount2;
static bool bOnce1            = false;
static double targetFrameTime = 1000.0 / 60.0;
static double t               = 0.0;
static u32 i                  = 0;

void
Init (const float fpsLimit) {
    if (fpsLimit > 0) LogMessage (LogLevel::INFO, "Init Fps Limiter");
    targetFrameTime = 1000.0 / fpsLimit;
}

void
Update () {
    if (!bOnce1) {
        bOnce1 = true;
        QueryPerformanceCounter (&PerformanceCount1);
        PerformanceCount1.QuadPart = PerformanceCount1.QuadPart >> i;
    }

    while (true) {
        QueryPerformanceCounter (&PerformanceCount2);

        if (t == 0.0) {
            LARGE_INTEGER PerformanceCount3;
            static bool bOnce2 = false;

            if (!bOnce2) {
                bOnce2 = true;
                QueryPerformanceFrequency (&PerformanceCount3);
                i      = 0;
                t      = 1000.0 / static_cast<double> (PerformanceCount3.QuadPart);
                if (auto v = t * 2147483648.0; 60000.0 > v) {
                    while (true) {
                        ++i;
                        v *= 2.0;
                        t *= 2.0;
                        if (60000.0 <= v) break;
                    }
                }
            }
            SleepEx (0, 1);
            break;
        }

        if (static_cast<double> ((PerformanceCount2.QuadPart >> i) - PerformanceCount1.QuadPart) * t >= targetFrameTime) break;

        SleepEx (0, 1);
    }

    QueryPerformanceCounter (&PerformanceCount2);
    PerformanceCount1.QuadPart = PerformanceCount2.QuadPart >> i;
}

} // namespace patches::FpsLimiter