ezLoop

A simple header-only C++ library that creates an efficient and reliable game loop. The implementation was designed with SFML in mind, however it is totally library-agonistic and can be used with any graphics library.

The looper takes care of all the boilerplate required to set up an efficient game loop, and can be implemented using a minimal amount of code.

The library separates the the loop into three distinct phases:

1. Input processing
2. Game state updating
3. Rendering

Rendering and input processing will occur as frequently as possible, whereas the update phase will occur at a customisable fixed interval.

Installation

Simply clone the repository and compile it yourself, or download one of the zip files from the releases section. Add the 'include' directory to the additional includes, and make sure that the linker is including the 'lib' directory and the 'ezloop.lib' file.

How to use

In order to interface with the Loop, the abstract base class GameBase will need to be implemented in a new class, and that class passed into the Loop constructor.

A minimal example is shown below.

#include <ezLoop/Loop.h>

// Implement the GameBase interface
class Game : public GameBase {
public:
	void processInput() override {
		// process input
	}
	void update() override {
		// update game state
	}
	void render(double extrapolation) override {
		// render game
	}
	bool isOpen() override {
		// when returns false, exit loop
	}
	
}

int main(int argc, char** argv) {
	// Create game and loop
	Game game;
	ez::Loop loop(game);

	// Begin loop
	loop.begin();

	return 0;
}

A runnable example can be found here

Game initialisation and logic can then be placed in the respective GameBase overrides.

Render will have one parameter, representing the extrapolation of the current frame. This value represents at which percentage in between updates the current frame was rendered. For example a value of 0.23f would represent that the frame was rendered 23% of the way between updates. This can be optionally used to create smooth rendering of moving objects on the screen.

Contribution

Accepting any and all contributes, feedback, advice, etc.

If there's an even better way of implementing this, I would love to learn.

Credits

Thanks to Robert Nystrom for his terrific explanation on different implementations of a game loop, from which this library references heavily. Go buy his book and support the great work he does.