annotate src/com/aurellem/capture/IsoTimer.java @ 73:877ae4b2993c tip

merge laptop changes.
author Robert McIntyre <rlm@mit.edu>
date Mon, 10 Mar 2014 18:58:08 -0400
parents a67aef438383
children
rev   line source
rlm@4 1 package com.aurellem.capture;
rlm@4 2
rlm@4 3 import com.jme3.system.Timer;
rlm@4 4
rlm@54 5 /**
rlm@54 6 * A standard JME3 application that extends SimpleApplication or
rlm@54 7 * Application tries as hard as it can to keep in sync with
rlm@54 8 * user-time. If a ball is rolling at 1 game-mile per game-hour in the
rlm@54 9 * game, and you wait for one user-hour as measured by the clock on
rlm@54 10 * your wall, then the ball should have traveled exactly one
rlm@54 11 * game-mile. In order to keep sync with the real world, the game
rlm@54 12 * throttles its physics engine and graphics display. If the
rlm@54 13 * computations involved in running the game are too intense, then the
rlm@54 14 * game will first skip frames, then sacrifice physics accuracy. If
rlm@56 15 * there are particularly demanding computations, then you may only
rlm@56 16 * get 1 fps, and the ball may tunnel through the floor or obstacles
rlm@56 17 * due to inaccurate physics simulation, but after the end of one
rlm@54 18 * user-hour, that ball will have traveled one game-mile.
rlm@54 19 *
rlm@54 20 * When we're recording video or audio, we don't care if the game-time
rlm@54 21 * syncs with user-time, but instead whether the time in the recorded
rlm@54 22 * video (video-time) syncs with user-time. To continue the analogy,
rlm@54 23 * if we recorded the ball rolling at 1 game-mile per game-hour and
rlm@54 24 * watched the video later, we would want to see 30 fps video of the
rlm@54 25 * ball rolling at 1 video-mile per user-hour. It doesn't matter how
rlm@54 26 * much user-time it took to simulate that hour of game-time to make
rlm@54 27 * the high-quality recording. If an Application uses this IsoTimer
rlm@54 28 * instead of the normal one, we can be sure that every call to
rlm@54 29 * simpleUpdate, for example, corresponds to exactly (1 / fps) seconds
rlm@59 30 * of game-time. This lets us record perfect video and audio even on
rlm@54 31 * a slow computer.
rlm@54 32 *
rlm@54 33 * @author Robert McIntyre
rlm@54 34 *
rlm@54 35 */
rlm@54 36
rlm@4 37 public class IsoTimer extends Timer {
rlm@4 38
rlm@62 39 private long framerate;
rlm@62 40 private int ticks;
rlm@4 41
rlm@62 42 public IsoTimer(float framerate){
rlm@62 43 this.framerate = (long) framerate;
rlm@62 44 this.ticks = 0;
rlm@62 45 }
rlm@62 46
rlm@62 47 public long getTime() {
rlm@70 48 return ticks;
rlm@62 49 }
rlm@62 50
rlm@62 51 public long getResolution() {
rlm@69 52 return framerate;
rlm@62 53 }
rlm@62 54
rlm@62 55 public float getFrameRate() {
rlm@69 56 return framerate;
rlm@62 57 }
rlm@62 58
rlm@62 59 public float getTimePerFrame() {
rlm@69 60 return (float) (1.0f / framerate);
rlm@62 61 }
rlm@62 62
rlm@62 63 public void update() {this.ticks++;}
rlm@62 64
rlm@62 65 public void reset() {this.ticks = 0;}
rlm@4 66
rlm@4 67 }