Timer/Stopwatch Not Accurate/Precise - Slow

Solar2D General Questions/Discussion
#1

Hey all,

I’m new to Corona and coding in general, but after looking to implement a timer/stopwatch in my game, I’ve created something which I think looks and generally works well but…

Although the logic seems fine to me, the time keeping is not 100% accurate.

I’ve tested it running alongside a real stopwatch and over the course of a minute it seems to lag a few seconds behind.

Can you spot where my logic and/or code is wrong? Or, is there some particular reason why this would be?

On a separate note, I tried to find some example code for a timer like this everywhere and could not. I think it’s suits a great variety of apps and games - puzzle, racing, etc. So, if people think that this would be useful to others, I’m going to post it the ‘Share Your Code’ section - when it’s working correctly of course.

Anyway, here’s what I have so far:

[lua]local _W, _H = display.contentWidth, display.contentHeight

local seconds, minutes, tenthSeconds
– Create basic start button (text)

local startButtonText = display.newText( “Tap To Start”, 0, 0, native.systemFont, 24 )
startButtonText.x = _W / 2; startButtonText.y = (_H / 2) + 80
startButtonText:setTextColor( 255, 255, 255 )
– Create basic start/stop button

local timerCount = display.newText( “00:00:0”, 0, 0, native.systemFont, 48 )
timerCount.x = _W / 2; timerCount.y = (_H / 2) - 40
timerCount:setTextColor( 255, 255, 255 )
local function startTimer(e)

startButtonText:removeSelf()
startButtonText = nil

function timerCount:timer( event )

local count = event.count

tenthSeconds = math.floor(count % 10)
seconds = math.floor(count / 10 ); seconds = math.floor(seconds % 60)
minutes = math.floor(count / 600); minutes = math.floor(minutes % 60)
timeFormat = string.format("%02d:%02d:%01d", minutes, seconds, tenthSeconds)
self.text = timeFormat

if count >= 6000 then
timer.cancel( event.source ) – Cancel timer after 10 mins
end

end
timer.performWithDelay( 100, timerCount, 6000 ) – Call timerCount function every 1/10th second for 10 minutes

end
– Tap event listener for start button (text)

startButtonText:addEventListener(“tap”, startTimer)[/lua] [import]uid: 74503 topic_id: 14675 reply_id: 314675[/import]

#2

One of the staff has a website, where they explain why this happens. Think it was something to do with fps. Also I think it said to us system.os or os.timer instead, you’ll have to try find the site or someone else may post it as I can’t remember it. [import]uid: 87611 topic_id: 14675 reply_id: 54271[/import]

#3

Thanks for the reply. Can’t seem to find the web site that you’re referring too though so if anyone can provide a link it would be appreciated.

So, what can I do to improve the accuracy of this timer model? Anything?

If not, what way is generally used to provide a similar, but more precise timer function? Are there samples around anywhere?

Thanks
[import]uid: 74503 topic_id: 14675 reply_id: 54293[/import]

#4

Yeah, you won’t get uber accurate timing. However, like Lewis said, use getTimer. It’s a # that always increases and uses like the sys clock.

You can do it like so. First, save this as “Timer.lua”:

[lua]Timer = {}

function Timer:new()
local ticker = {}
ticker.lastTick = system.getTimer()
ticker.paused = true
ticker.totalTime = 0

function ticker:enterFrame(event)
local lastTick = self.lastTick
local now = system.getTimer()
local difference = now - lastTick
self.lastTick = now
self.totalTime = self.totalTime + difference
end

function ticker:pause()
self.paused = true
Runtime:removeEventListener(“enterFrame”, self)
end

function ticker:reset()
self.lastTick = system.getTimer()
end

function ticker:unpause()
if self.paused == true then
self.paused = false
Runtime:removeEventListener(“enterFrame”, self)
self.lastTick = system.getTimer()
end
end

function ticker:start()
Runtime:removeEventListener(“enterFrame”, self)
self.paused = false
Runtime:addEventListener(“enterFrame”, self)
end

return ticker
end

return Timer[/lua]

And then you can use it like so:

[lua]require “Timer”

timer = Timer:new()
timer:start()

function printTime(event)
print("time: “, (timer.totalTime / 1000) … " seconds”)
end

function togglePause()
if timer.paused == false then
timer:pause()
else
timer:unpause()
end
end

Runtime:addEventListener(“enterFrame”, printTime)[/lua]

Create your own button to call togglePause().
[import]uid: 23693 topic_id: 14675 reply_id: 54311[/import]