1 /*
2  * Copyright (c) 2009-2010 jMonkeyEngine
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions are
7  * met:
8  *
9  * * Redistributions of source code must retain the above copyright
10  *   notice, this list of conditions and the following disclaimer.
11  *
12  * * Redistributions in binary form must reproduce the above copyright
13  *   notice, this list of conditions and the following disclaimer in the
14  *   documentation and/or other materials provided with the distribution.
15  *
16  * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
17  *   may be used to endorse or promote products derived from this software
18  *   without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
24  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
26  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
27  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
28  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
29  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
30  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 package com.jme3.system;
34 
35 /**
36  * <code>NanoTimer</code> is a System.nanoTime implementation of <code>Timer</code>.
37  * This is primarily useful for headless applications running on a server.
38  *
39  * @author Matthew D. Hicks
40  */
41 public class NanoTimer extends Timer {
42 
43     private static final long TIMER_RESOLUTION = 1000000000L;
44     private static final float INVERSE_TIMER_RESOLUTION = 1f/1000000000L;
45 
46     private long startTime;
47     private long previousTime;
48     private float tpf;
49     private float fps;
50 
NanoTimer()51     public NanoTimer() {
52         startTime = System.nanoTime();
53     }
54 
55     /**
56      * Returns the time in seconds. The timer starts
57      * at 0.0 seconds.
58      *
59      * @return the current time in seconds
60      */
61     @Override
getTimeInSeconds()62     public float getTimeInSeconds() {
63         return getTime() * INVERSE_TIMER_RESOLUTION;
64     }
65 
getTime()66     public long getTime() {
67         return System.nanoTime() - startTime;
68     }
69 
getResolution()70     public long getResolution() {
71         return TIMER_RESOLUTION;
72     }
73 
getFrameRate()74     public float getFrameRate() {
75         return fps;
76     }
77 
getTimePerFrame()78     public float getTimePerFrame() {
79         return tpf;
80     }
81 
update()82     public void update() {
83         tpf = (getTime() - previousTime) * (1.0f / TIMER_RESOLUTION);
84         fps = 1.0f / tpf;
85         previousTime = getTime();
86     }
87 
reset()88     public void reset() {
89         startTime = System.nanoTime();
90         previousTime = getTime();
91     }
92 }
93