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clanlib0.8-docs-0.8.1-22.mga7.i586.rpm


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<div style="border-bottom-style: dotted;  border-bottom-width: 1px; margin-bottom: 1em;"><h2>Tips and tricks</h2></div>



<div style="border-bottom-style: dotted;  border-bottom-width: 1px;"><h3>Calculating frames per second (fps)</h3></div>
<p>Author: Sphair</p>

<p>Often you want to know how fast or slow your game is running, and displaying
a FPS counter can be a handy debug-tool.</p>

<ul><pre><font face="Arial,Courier New,Courier">class Game
{
public:
	void run();
	void update();
	void draw();

	int calc_fps(int frame_time);

	CL_Font font_fps;
	int fps;
};

void Game::run()
{
	CL_ResourceManager resources("resources.xml");
	font_fps = CL_Font("font_gray", &resources);

	while(!CL_Keyboard::get_keycode(CL_KEY_ESCAPE))
	{
		update();
		draw();

		CL_Display::flip();
		CL_System::keep_alive();
	};
}

void Game::update()
{
	// Calculate time since last update
	static int start_time = CL_System::get_time();
	
	int cur_time = CL_System::get_time();
	int delta_time = cur_time - start_time;
	start_time = cur_time;

	fps = calc_fps(delta_time);
}

int Game::calc_fps(int frame_time)
{
	static int fps_result = 0;
	static int fps_counter = 0;
	static int total_time = 0;
	
	total_time += frame_time;
	if(total_time &gt;= 1000)	// One second has passed
	{
		fps_result = fps_counter + 1;
		fps_counter = total_time = 0;
	}
	fps_counter++;	// Increase fps

	return fps_result;
}

void Game::draw()
{
	CL_Display::clear();
	
	font_fps.draw(0, 0, "fps: " + CL_String::from_int(fps));
}
</font></pre></ul>

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