d2d.core.fpslimiter source code

1 module d2d.core.fpslimiter;
2 
3 import core.thread;
4 import std.datetime;
5 
6 /**
7  * Class for limiting your FPS.
8  * Examples:
9  * ---
10  * FPSLimiter limiter = new FPSLimiter(25);
11  * while(window.open)
12  * {
13  *     window.clear();
14  *     // Draw and Update stuff
15  *     window.display();
16  *     limiter.wait();
17  * }
18  * ---
19  */
20 class FPSLimiter
21 {
22 protected:
23 	int _fps = 0;
24 	int _skiphns = 0;
25 	ulong _next = 0;
26 	long _sleep = 0;
27 
28 public:
29 	/// Creates a new FPS Limiter instance with specified max FPS.
30 	this(int maxFPS)
31 	{
32 		_fps = maxFPS;
33 		_skiphns = 10_000_000 / _fps;
34 		_next = Clock.currStdTime();
35 	}
36 
37 	/// Calculates how long to wait and then waits that amount of time to ensure the target FPS.
38 	void wait()
39 	{
40 		_next += _skiphns;
41 		_sleep = _next - Clock.currStdTime();
42 		if (_sleep > 0)
43 		{
44 			Thread.sleep(dur!("hnsecs")(_sleep));
45 		}
46 	}
47 }