view src/com/aurellem/capture/IsoTimer.java @ 70:a67aef438383

minor fix.
author Robert McIntyre <rlm@mit.edu>
date Wed, 29 May 2013 17:31:16 -0400
parents ddb300c5335f
children
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1 package com.aurellem.capture;
3 import com.jme3.system.Timer;
5 /**
6 * A standard JME3 application that extends SimpleApplication or
7 * Application tries as hard as it can to keep in sync with
8 * user-time. If a ball is rolling at 1 game-mile per game-hour in the
9 * game, and you wait for one user-hour as measured by the clock on
10 * your wall, then the ball should have traveled exactly one
11 * game-mile. In order to keep sync with the real world, the game
12 * throttles its physics engine and graphics display. If the
13 * computations involved in running the game are too intense, then the
14 * game will first skip frames, then sacrifice physics accuracy. If
15 * there are particularly demanding computations, then you may only
16 * get 1 fps, and the ball may tunnel through the floor or obstacles
17 * due to inaccurate physics simulation, but after the end of one
18 * user-hour, that ball will have traveled one game-mile.
19 *
20 * When we're recording video or audio, we don't care if the game-time
21 * syncs with user-time, but instead whether the time in the recorded
22 * video (video-time) syncs with user-time. To continue the analogy,
23 * if we recorded the ball rolling at 1 game-mile per game-hour and
24 * watched the video later, we would want to see 30 fps video of the
25 * ball rolling at 1 video-mile per user-hour. It doesn't matter how
26 * much user-time it took to simulate that hour of game-time to make
27 * the high-quality recording. If an Application uses this IsoTimer
28 * instead of the normal one, we can be sure that every call to
29 * simpleUpdate, for example, corresponds to exactly (1 / fps) seconds
30 * of game-time. This lets us record perfect video and audio even on
31 * a slow computer.
32 *
33 * @author Robert McIntyre
34 *
35 */
37 public class IsoTimer extends Timer {
39 private long framerate;
40 private int ticks;
42 public IsoTimer(float framerate){
43 this.framerate = (long) framerate;
44 this.ticks = 0;
45 }
47 public long getTime() {
48 return ticks;
49 }
51 public long getResolution() {
52 return framerate;
53 }
55 public float getFrameRate() {
56 return framerate;
57 }
59 public float getTimePerFrame() {
60 return (float) (1.0f / framerate);
61 }
63 public void update() {this.ticks++;}
65 public void reset() {this.ticks = 0;}
67 }