simple question about the Timer

Engines, Libraries and Tools Java 3D
#1

I know that this hi res Timer thing has been discussed to death, but please bear with me, I am new to this. The following is just simple code to display the value of the Java3DTimer:

import com.sun.j3d.utils.timer.J3DTimer;
class test
{
public static void main(String[] args)
{
long time;
time = J3DTimer.getValue();
System.out.println(time);
}
}

When I run the code here is the oputput:
5993877065139

My question is what exactly does this number mean? And how can I use this timer to have an accurate frame rate. I have a simple program with an animation loop and the statement thread.sleep(30) which is 30ns. Ofcourse this is inaccurate. I was wondering how exactly do I implement the Java3DTimer in my animation loop?

Also what is WakeupOnElapsedTime(30) about? and how is it used?
Any help is greatly appreciated.

#2

The number means absolutely nothing. You can just use it to calculate differences of these which gives you quite accurately the time between two calls of J3DTimer.getValue(), measured in nanoseconds.

Thread.sleep(30) sleeps for 30 milliseconds, not nanoseconds. So executing J3DTimer.getValue() before and after the sleep should yield a difference of 30*1000000, rounds about.

WakeupOnElapsedTime(30) is related to Thread.sleep(30) somehow, just synchronized with Java3D.
WakeupOnElapsedTime(30) is a good mean to drive a gameloop with ~30FPS. Triggered by WakeupOnElapsedTime(), we measure times exactly with J3DTimer.getValue() then.

#3

I dont understan exactly. So instead of thread.sleep(30) I should use WakeupOnElapsedTime(30)? where does the java3DTimer go?

while (true)
{
sprite.updateposition
sprite.draw

try { thread.sleep(30)

catch …
}
Here is a simple animation loop (pseudo code) that I am using. Where can I implement WakeupOnElapsedTime(30) or java3DTimer in order to have a better refresh rate? Also wich packages do I need to import for WakeupOnElapsedTime(30)?