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
33package com.jme3.system.lwjgl;
34
35import com.jme3.system.Timer;
36import java.util.logging.Level;
37import java.util.logging.Logger;
38import org.lwjgl.Sys;
39
40/**
41 * <code>Timer</code> handles the system's time related functionality. This
42 * allows the calculation of the framerate. To keep the framerate calculation
43 * accurate, a call to update each frame is required. <code>Timer</code> is a
44 * singleton object and must be created via the <code>getTimer</code> method.
45 *
46 * @author Mark Powell
47 * @version $Id: LWJGLTimer.java,v 1.21 2007/09/22 16:46:35 irrisor Exp $
48 */
49public class LwjglTimer extends Timer {
50    private static final Logger logger = Logger.getLogger(LwjglTimer.class
51            .getName());
52
53    //frame rate parameters.
54    private long oldTime;
55    private long startTime;
56
57    private float lastTPF, lastFPS;
58
59    private final static long LWJGL_TIMER_RES = Sys.getTimerResolution();
60    private final static float INV_LWJGL_TIMER_RES = ( 1f / LWJGL_TIMER_RES );
61
62    public final static long LWJGL_TIME_TO_NANOS = (1000000000 / LWJGL_TIMER_RES);
63
64    /**
65     * Constructor builds a <code>Timer</code> object. All values will be
66     * initialized to it's default values.
67     */
68    public LwjglTimer() {
69        reset();
70        logger.log(Level.INFO, "Timer resolution: {0} ticks per second", LWJGL_TIMER_RES);
71    }
72
73    public void reset() {
74        startTime = Sys.getTime();
75        oldTime = getTime();
76    }
77
78    @Override
79    public float getTimeInSeconds() {
80        return getTime() * INV_LWJGL_TIMER_RES;
81    }
82
83    /**
84     * @see com.jme.util.Timer#getTime()
85     */
86    public long getTime() {
87        return Sys.getTime() - startTime;
88    }
89
90    /**
91     * @see com.jme.util.Timer#getResolution()
92     */
93    public long getResolution() {
94        return LWJGL_TIMER_RES;
95    }
96
97    /**
98     * <code>getFrameRate</code> returns the current frame rate since the last
99     * call to <code>update</code>.
100     *
101     * @return the current frame rate.
102     */
103    public float getFrameRate() {
104        return lastFPS;
105    }
106
107    public float getTimePerFrame() {
108        return lastTPF;
109    }
110
111    /**
112     * <code>update</code> recalulates the frame rate based on the previous
113     * call to update. It is assumed that update is called each frame.
114     */
115    public void update() {
116        long curTime = getTime();
117        lastTPF = (curTime - oldTime) * (1.0f / LWJGL_TIMER_RES);
118        lastFPS = 1.0f / lastTPF;
119        oldTime = curTime;
120    }
121
122    /**
123     * <code>toString</code> returns the string representation of this timer
124     * in the format: <br>
125     * <br>
126     * jme.utility.Timer@1db699b <br>
127     * Time: {LONG} <br>
128     * FPS: {LONG} <br>
129     *
130     * @return the string representation of this object.
131     */
132    @Override
133    public String toString() {
134        String string = super.toString();
135        string += "\nTime: " + oldTime;
136        string += "\nFPS: " + getFrameRate();
137        return string;
138    }
139}