Millisecond timer???

techdojo · July 2012

I don't know if this has been asked already or if I'm just being blind, dumb and or stupid?
Is there a way (function or undocumented "feature") to retrieve a millisecond count / timer from some arbitrary point?

I'm tracking a value when a mouse move event occurs so I can accurately track velocity on a list view control but for the life of me I can't seem to find a way to get some accurate timings.

Anyone got a suggestion?

TIA

atilim · July 2012

first!

http://www.giderosmobile.com/documentation/reference_manual.html#os.timer
Returned value is in seconds and this function uses the finest resolution timer for each platform

ar2rsawseen · July 2012

better!

sometimes seconds are too large amount of time, when you are debugging the performance. You can include socket.lua file in your Gideros project and use socket.gettime()*1000 to get miliseconds

--define some starting time
start = socket.gettime()*1000
 
--and then use this function, to get time from starting point
function getTime()
	return socket.gettime()*1000 - start
end

atilim · July 2012

but!

os.timer() returns double precision value and provides sub-millisecond accuracy

ar2rsawseen · July 2012

why!

it's not mentioned in docs?

atilim · July 2012

LOL!

but it says "precise" in the docs.. uhmm.. :-\"

ar2rsawseen · July 2012

sure!

you could also state: you can set different properties for Sprite object using set method. Why bother listing them all? :P

atilim · July 2012

) now I'm speechless

gorkem · July 2012

)

techdojo · July 2012

Thanks for the responses, sorry about starting a fight between you guys

maybe I'll use both methods and let them fight it out.

@Atilim I noticed the os.timer docs said returned a value in seconds - I didn't realise the precision was good enough to just multiply the value by 1000, no worries. I feel your pain I try to not have to write documentation if I can avoid it

ar2rsawseen · July 2012

@techdojo we weren't fighting.
We were simply "techdojscousering"

chipster123 · July 2012

This thread was more entertaining than what's on TV!

Scouser · July 2012

@ar2rsawseen & @chipster123

)

techdojo · July 2012

@ar2rsawseen - not if you didn't make him coffee afterwards you wern't

)

Mells · July 2012

Sorry but can somebody provide a very simple case to use this function?
The purpose, and the implementation (basic code sample).

It seems that I have been doing the same thing by using timer.new so I must misunderstand the purpose of this function.

techdojo · July 2012

I'm using the time to track the velocity of a list control - it's based on some Corona code which supply's this information as part of the Touch and EnterFrame events (event.time) - I don't 100% understand exactly what's going on (more experimentation required) however it seems to work fine and my list control "appears" to behave the same as the one in the demo.

To implement it I created a local function

local function msTimer() return math.floor(os.timer() * 1000) end

And call that to get the value.

atilim · July 2012

@Mells if you need a precise clock, then this function is for you.

for example, gtween.lua uses it to synchronize the tween according to time. as @techdojo said, one other usage is calculating the velocity of a swipe. and most probably @GregBug uses it in TNT Animator to precisely control timed based animation.

GregBUG · July 2012

yes as said @atilim
i used os.timer() in tnt animator and also on tnt particles engine.

ar2rsawseen · July 2012

And no one uses it to debug the performance of app? Which parts are taking longer to load, etc?

GregBUG · July 2012

And no one uses it to debug the performance of app? Which parts are taking longer to load, etc?

yes of course.

for ex. i used to test to see if lua math.sin / math.cos was slower than (look-up table) sin/cos table.

techdojo · July 2012

And no one uses it to debug the performance of app? Which parts are taking longer to load, etc?

Simples - don't write slow code... :-\"

ar2rsawseen · July 2012

@techdojo

) Sure.
Or you wanted to say, that guys like @atilim are sensing code execution time, they don't need to measure it at all.
@atilim when starting Gideros app:
Whoops, it feels like this asset loaded by half of a millisecond longer than usual, need to fix that right now

techdojo · July 2012

Of course, you mean you didn't know that the force is strong with this @atilim, a powerful coder is he. In him I sense much code.

Btw - the os.timer thing worked perfectly!

glennbjr · July 2012

@techdojo Great, now I have a sudden urge to watch Star Wars movies all day now. :-))

Magnusviri · July 2012

for ex. i used to test to see if lua math.sin / math.cos was slower than (look-up table) sin/cos table.

Which was faster?

GregBUG · July 2012

for ex. i used to test to see if lua math.sin / math.cos was slower than (look-up table) sin/cos table.
Which was faster?

math.sin and math.cos are much more faster!

atilim · July 2012

@ar2rsawseen @techdojo

)

techdojo · July 2012

@techdojo Great, now I have a sudden urge to watch Star Wars movies all day now. :-))

And that's a bad thing - why?

(unless your starting with Episode 1 - but let's not go there...

Mells · July 2012

@techdojo, @atilim
Thanks for the clarifications, but I am not sure I totally get it.

Example
In a racing game (Mario Kart) at the beginning of the race : "Ready.... go!" and from there a counter is running until the player finishes the race.
Currently I create a timer, stop it, and start it at "go!".
Then I stop it when the player reaches the end of the race.

What would be different with os.timer?

From what I could understand, the only difference lies in the precision?

What would be the best way to get the time between two events (push button1, then push button2)?

Scouser · July 2012

@Mells: I think that is the whole point of this thread.

In the event for button1 you use time1=os.timer() and in the event for button2 use time2=os.timer() then the the number of milliseconds between button1 and button2 would be deltams = (time2-time1)*1000, no need to setup a timer.

Mells · July 2012

@Scouser
I didn't understand how to use it and if precision was the *only* difference.
Now I do, thank you

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