project64/Source/Project64-core/N64System/SpeedLimiter.cpp

#include "stdafx.h"

#include "Project64-core/N64System/SpeedLimiter.h"

#include <Common/Util.h>

const uint32_t CSpeedLimiter::m_DefaultSpeed = 60;

CSpeedLimiter::CSpeedLimiter() :
    m_Frames(0),
    m_Speed(m_DefaultSpeed),
    m_BaseSpeed(m_DefaultSpeed)
{
}

CSpeedLimiter::~CSpeedLimiter()
{
}

void CSpeedLimiter::SetHertz(uint32_t Hertz)
{
    m_Speed = Hertz;
    m_BaseSpeed = Hertz;
    FixSpeedRatio();
}

void CSpeedLimiter::FixSpeedRatio()
{
    m_MicroSecondsPerFrame = 1000000 / m_Speed;
    m_Frames = 0;
}

bool CSpeedLimiter::Timer_Process(uint32_t * FrameRate)
{
    m_Frames += 1;
    HighResTimeStamp CurrentTime;
    CurrentTime.SetToNow();

    // Calculate time that should have elapsed for this frame
    uint64_t LastTime = m_LastTime.GetMicroSeconds(), CurrentTimeValue = CurrentTime.GetMicroSeconds();
    if (LastTime == 0)
    {
        m_Frames = 0;
        m_LastTime = CurrentTime;
        return true;
    }
    uint64_t CalculatedTime = LastTime + (m_MicroSecondsPerFrame * m_Frames);
    if (CurrentTimeValue < CalculatedTime)
    {
        int32_t time = (int)(CalculatedTime - CurrentTimeValue);
        if (time > 0)
        {
            pjutil::Sleep((time / 1000) + 1);
        }
        // Refresh current time
        CurrentTime.SetToNow();
        CurrentTimeValue = CurrentTime.GetMicroSeconds();
    }
    if (CurrentTimeValue - LastTime >= 1000000)
    {
        // Output FPS
        if (FrameRate != nullptr)
        {
            *FrameRate = m_Frames;
        }
        m_Frames = 0;
        m_LastTime = CurrentTime;
        return true;
    }
    return false;
}

void CSpeedLimiter::AlterSpeed(const ESpeedChange SpeedChange)
{
    int32_t SpeedFactor = 1;
    if (SpeedChange == DECREASE_SPEED)
    {
        SpeedFactor = -1;
    }

    if (m_Speed >= m_DefaultSpeed)
    {
        m_Speed += 10 * SpeedFactor;
    }
    else if (m_Speed >= 15)
    {
        m_Speed += 5 * SpeedFactor;
    }
    else if ((m_Speed > 1 && SpeedChange == DECREASE_SPEED) || SpeedChange == INCREASE_SPEED)
    {
        m_Speed += 1 * SpeedFactor;
    }

    SpeedChanged(m_Speed);
    FixSpeedRatio();
}

void CSpeedLimiter::SetSpeed(int Speed)
{
    if (Speed < 1)
    {
        Speed = 1;
    }
    m_Speed = Speed;
    SpeedChanged(m_Speed);
    FixSpeedRatio();
}

int CSpeedLimiter::GetSpeed(void) const
{
    return m_Speed;
}

int CSpeedLimiter::GetBaseSpeed(void) const
{
    return m_BaseSpeed;
}