From: Dennis Ranke <mail@...>
Date: 2005-11-11T18:17:14+09:00
Subject: Re: Accurate Timing in ruby

Kero wrote:
>> Believe it or not, I'm attempting to make an action-driven game with ruby
>>   Is there a way to get the time in milliseconds since the program start
>> ed, or something similar?  I've tried using Time.now.to_f, but all too of
>> ten that value will be the same in two consecutive update calls, causing
>> jumps in motion and "infinite" fps readings.
> 
> [...]
> 
> I fear what you see is not Ruby's fault, but your hardware/OS clock.
> 1) your hardware is so fast that the consecutive calls have no
>    significant distinguishing bits left (I have 2 or 3 bits left on 700
>    MHz; you may need nanoseconds instead of microseconds)
> 2) your OS is not updating its system clock often enough
> 
> Even though windows has nasty habits when updating time to a central
> server, I do not think it suffers from 2)

In my experience it does:

irb(main):006:0> a=Time.now;while Time.now==a;end;Time.now-a
=> 0.01

ie. Time.now only gives you the time in centiseconds.

I would recommend the initial poster to use one of the SDL bindings, if 
possible, which include methods to query the time much more accurately.

Dennis