anchovy.gui.timer source code

1 /*
2 Copyright (c) 2013 Andrey Penechko
3 
4 Boost Software License - Version 1.0 - August 17th, 2003
5 
6 Permission is hereby granted, free of charge, to any person or organization
7 obtaining a copy of the software and accompanying documentation covered by
8 this license the "Software" to use, reproduce, display, distribute,
9 execute, and transmit the Software, and to prepare derivative works of the
10 Software, and to permit third-parties to whom the Software is furnished to
11 do so, all subject to the following:
12 
13 The copyright notices in the Software and this entire statement, including
14 the above license grant, this restriction and the following disclaimer,
15 must be included in all copies of the Software, in whole or in part, and
16 all derivative works of the Software, unless such copies or derivative
17 works are solely in the form of machine-executable object code generated by
18 a source language processor.
19 
20 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
23 SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
24 FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
25 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
26 DEALINGS IN THE SOFTWARE.
27 */
28 
29 module anchovy.gui.timer;
30 
31 import core.time;
32 import std.math: isNaN, trunc;
33 
34 import anchovy.gui;
35 
36 /// Handler must number > 0 if custom repeat needed.
37 /// Timer will be added to queue again with nextTime set to number.
38 /// If number = 0 then nextTime will be set to Timer.delay.
39 /// If number < 0 or is nan, timer will be removed from queue.
40 alias double delegate(double dt) TimerHandler;
41 
42 enum TimerTickType
43 {
44 	PROCESS_ALL_UNORDERED,
45 	PROCESS_ALL_ORDERED,
46 	PROCESS_LAST,
47 }
48 
49 /// Provides basic timer functionality.
50 /// Designed to be used with TimerManager.
51 class Timer
52 {
53 	/// Used for initializing timer.
54 	/// Params:
55 	/// 	delay specifies the delay after which handler will be called.
56 	/// 	handler specifies handler to be called when delay exceeds.
57 
58 	/// 	tickType sets processing method to be used with this timer.
59 	void init(double _firstTime, double _currentTime, double _delay, TimerHandler _handler, TimerTickType _tickType = TimerTickType.init)
60 	in
61 	{
62 		assert(_handler);
63 		assert(_delay > 0);
64 		assert(_firstTime > 0);
65 		assert(_currentTime > 0);
66 	}
67 	body
68 	{
69 		delay = _delay;
70 		lastUpdateTime = _currentTime;
71 		handler = _handler;
72 		tickType = _tickType;
73 		nextUpdateTime = _firstTime;
74 	}
75 
76 	/// The whole delta time will be provided if currentTime > nextTime even when dt % thisDelay > 1.
77 	/// Timer will automaticaly decide to process only one period, or all. It can also process only the last update if needed.
78 	/// This method will be called only when currentTime > nextTime.
79 	void tick(double currentTime)
80 	{
81 		void updateNextTime(double newNextTime)
82 		{
83 			lastUpdateTime = nextUpdateTime;
84 
85 			if (newNextTime == 0)
86 				nextUpdateTime += delay;
87 			else if (newNextTime > 0)
88 				nextUpdateTime += newNextTime;
89 			else
90 				nextUpdateTime = double.nan;
91 		}
92 
93 		double newNextTime;
94 		
95 		with(TimerTickType)
96 		final switch(tickType)
97 		{
98 			case PROCESS_ALL_ORDERED:
99 			{
100 				newNextTime = handler(nextUpdateTime - lastUpdateTime);
101 				updateNextTime(newNextTime);
102 				break;
103 			}
104 			case PROCESS_ALL_UNORDERED:
105 			{
106 				while(currentTime > nextUpdateTime)
107 				{
108 					newNextTime = handler(nextUpdateTime - lastUpdateTime);
109 					updateNextTime(newNextTime);
110 				}
111 				break;
112 			}
113 			case PROCESS_LAST:
114 			{
115 				uint timesUpdated = cast(uint)trunc((currentTime - nextUpdateTime) / delay) + 1;
116 				nextUpdateTime += timesUpdated * delay;
117 
118 				newNextTime = handler(timesUpdated);
119 				updateNextTime(newNextTime);
120 				break;
121 			}
122 		}
123 	}
124 	
125 	TimerHandler handler;
126 
127 	TimerTickType tickType;
128 
129 	double lastUpdateTime;
130 	double nextUpdateTime;
131 	double delay;
132 }