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timing

contents

clock
count
timer

This is still very much under development... in fact I am not even sure if it is the best way to do it. If you think of a better way to do this I would be delighted to hear it. Clearly there is a very good reason why timing in VRML is such a terrible mess: it really is a difficult thing to design well.

I have already developed the vary curve parameter in a number of attributes. I was really happy with it until I realised that it had multiple applications in the sound attribute (it should be able to alter volume, filter, echo, and various other things). That was the main reason I started trying for this more general solution. It may be a complete stuff-up and I should just work on the vary parameter more, or I may be on the right track. I am not sure just now.

Each of these uses a schedule to ensure timing-related effects occur when they are intended to. The list doesn't actually need to be in order (though it helps human readers if it is). That means that new items can be scheduled or old ones can be altered under program control.

clock

Clock lets you schedule a list of things that you want done at particular times. The list consists of absolute datetimes that cause named objects, attributes or variables to be sent the contents of variables or constants.

There are several ways that the time format can be specified for the clock scheduler.

  • time - hh:mm:ss.ss
  • euro - dd/mm/yyyy hh:mm:ss.ss
  • us - mm/dd/yyyy hh:mm:ss.ss
  • ordered - yyyy_mm_dd_hh_mm_ss.ss
  • gmt - yyyy_mm_dd_hh_mm_ss.ss (but GMT time)
  • day - day of week (Friday, Sunday, etc)
  • month - month of the year (January, May, etc)
  • dayseconds - seconds since midnight
  • yearseconds - seconds since the beginning of this year
  • jan70 - seconds since the 1st of January 1970
    • clock
	flag
	unit time_units
	alarm [
		time name value
		time name value
		time name value
		...

    count

    Count lets you schedule things based upon counts received. 

    count
	flag
	alarm
		ncount name value
		ncount name value
		ncount name value
		...
	repeat n

    timer

    Timer is like the clock but instead of working from actual datetime it starts a timer running from zero. 

    timer
	flag
	alarm
		delay name value
		delay name value
		delay name value
		...
	repeat n


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