[Squeakland] drive-a-car newbie questions

Andreas Raab andreas.raab at squeakland.org
Sun Feb 29 19:11:32 PST 2004

Hi Ken,

> 1. So if a tick is a specified number of milliseconds then what happens
> when too much is happening during a cycle for the computer to be able to
> handle in "tick" milliseconds?

The eToy system does not allow you to run any more ticks per second than it
is able to update graphically. So if you request a thousand ticks per second
and we only have an update rate of (say) 15 ticks per second you get 15
ticks per second.

> 2. Or instead if the tick is in Squeak time units what relationship
> does it have to the passage of time my watch shows?

A very vague relation ;-) Seriously, this is one of the things that we want
to address via Croquet where the relation between "real time" and
"simulation time" is defined in a different way. Right now one should think
about ticks as "maximum ticks per second" not as "actual ticks per second".

> Underlying my questions is the desire to be able to set a speed so that
> a car takes, for example, exactly 5 seconds to travel 100 units
> (pixels?) at a constant speed.

Strictly speaking, this isn't possible in eToys - there is simply no
garantuee by the system that it will execute the scripts at precisely the
speed you are indicating.

  - Andreas

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