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Tips and tricks

Abstract:

This overview will contain small tips and tricks on various topics.

Calculating frames per second (fps)

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

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.scr", false);
	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 >= 1000)	// One second has passed
	{
		fps_result = fps_counter;
		fps_counter = total_time = 0;
	}
	else
		fps_counter++;	// Less than one second, increase fps

	return fps_result;
}

void Game::draw()
{
	CL_Display::clear();
	
	font_fps.draw(0, 0, "fps: " + CL_String(fps));
}