KlaoudeEngine/src/Timing.cpp at master · klaoude/KlaoudeEngine · GitHub

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#include "Timing.h"

#include <SDL.h>

namespace KlaoudeEngine
{
	FpsLimiter::FpsLimiter()
	{

	}

	void FpsLimiter::init(float maxFPS)
	{
		setMaxFPS(maxFPS);
	}

	void FpsLimiter::setMaxFPS(float maxFPS)
	{
		m_maxFPS = maxFPS;
	}

	void FpsLimiter::begin()
	{
		m_startTicks = SDL_GetTicks();
	}

	float FpsLimiter::end()
	{
		calculateFPS();

		float frameTicks = SDL_GetTicks() - m_startTicks;

		if (1000.0f / m_maxFPS > frameTicks)
			SDL_Delay(1000.0f / m_maxFPS - frameTicks);

		return m_fps;
	}

	void FpsLimiter::calculateFPS()
	{
		static const int NUM_SAMPLES = 10;
		static float frameTimes[NUM_SAMPLES];
		static int currentFrame = 0;

		static float prevTicks = SDL_GetTicks();

		float currentTicks;
		currentTicks = SDL_GetTicks();

		m_frameTime = currentTicks - prevTicks;
		frameTimes[currentFrame % NUM_SAMPLES] = m_frameTime;

		prevTicks = currentTicks;

		int count;

		currentFrame++;
		if (currentFrame < NUM_SAMPLES)
			count = currentFrame;
		else
			count = NUM_SAMPLES;

		float frameTimeAverage = 0;
		for (int i = 0; i < count; i++)
			frameTimeAverage += frameTimes[i];
		frameTimeAverage /= count;

		if (frameTimeAverage > 0)
			m_fps = 1000.0f / frameTimeAverage;
		else
			m_fps = 60.0f;
	}
}