Initial Mercurial commit.

src/modules/timer/sdl/Timer.h

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+/**
+* Copyright (c) 2006-2009 LOVE Development Team
+* 
+* This software is provided 'as-is', without any express or implied
+* warranty.  In no event will the authors be held liable for any damages
+* arising from the use of this software.
+* 
+* Permission is granted to anyone to use this software for any purpose,
+* including commercial applications, and to alter it and redistribute it
+* freely, subject to the following restrictions:
+* 
+* 1. The origin of this software must not be misrepresented; you must not
+*    claim that you wrote the original software. If you use this software
+*    in a product, an acknowledgment in the product documentation would be
+*    appreciated but is not required.
+* 2. Altered source versions must be plainly marked as such, and must not be
+*    misrepresented as being the original software.
+* 3. This notice may not be removed or altered from any source distribution.
+**/
+
+#ifndef LOVE_TIMER_SDL_TIMER_H
+#define LOVE_TIMER_SDL_TIMER_H
+
+// SDL
+#include <SDL.h>
+
+// LOVE
+#include <common/Module.h>
+
+namespace love
+{
+namespace timer
+{
+namespace sdl
+{
+	/**
+	* An SDL timer module. Can keep track of time between certain function
+	* calls, and provides access to a FPS metric which updates once each second.
+	**/
+	class Timer : public Module
+	{
+	private:
+
+		// Timing vars for benchmarking.
+		Uint32 time_init;
+		
+		// Frame delta vars.
+		Uint32 currTime;
+		Uint32 prevTime;
+		Uint32 prevFpsUpdate;
+
+		// Updated with a certain frequency.
+		float fps;
+
+		// The frequency by which to update the FPS.
+		float fpsUpdateFrequency;
+
+		// Frames since last FPS update.
+		int frames;
+
+		// The current timestep.
+		float dt;
+
+	public:
+
+		/**
+		* Constructor. Initializes the SDL/timer subsystem.
+		**/
+		Timer();
+
+		/**
+		* Destructor.
+		**/
+		~Timer();
+
+		/**
+		* Gets the name of the module.
+		* @return Always returns "love.timer.sdl".
+		**/
+		const char * getName() const;
+		
+		/**
+		* Measures the time between this call and the previous call, 
+		* and updates internal values accordinly.
+		**/
+		void step();
+
+		/**
+		* Tries to sleep for the specified amount of time. The precision is
+		* usually 1ms.
+		* @param ms The number of milliseconds to sleep for.
+		**/
+		void sleep(unsigned int ms);
+
+		/**
+		* Gets the time between the last two frames, assuming step is called
+		* each frame.
+		**/
+		float getDelta() const;
+
+		/**
+		* Gets the average FPS over the last second. Beucase the value is only updated
+		* once per second, it does not look erratic when displayed on screen.
+		* @return The "current" FPS. 
+		**/
+		float getFPS() const;
+
+		/**
+		* Gets the amount of time since the program started. Only useful for timing
+		* code or measuring intervals.
+		* @return The time (in seconds) since the program started.
+		**/
+		float getTime() const;
+
+	}; // Timer
+
+} // sdl
+} // timer
+} // love
+
+#endif // LOVE_TIMER_SDL_TIMER_H