A very basic feature requset, run an action on a sprite

alexzheng · August 2012

Since @atilim told me MovieClip is not suitable for running actions on a sprite,
I began turning to GTween again, however, it was full of bugs, and the performance was not acceptable.
The result of the code will not be the same as expected,the larger number of loops, the worse the result was.

local sprite
local gtween
local counter = 0
for i = 1, 100 do
sprite = Bitmap.new(Texture.new("box.png"))
stage:addChild(sprite)
 
gtween = GTween.new(sprite, 0.1, {x = 240}, {delay = 0.1 * i, ease = easing.outBounce, repeatCount = 1, reflect = true})
gtween:addEventListener("complete", function(data) counter = counter + 1 print(data, counter) end, i)
gtween.dispatchEvents = true
end

john26 · August 2012

I've been using GTween extensively and haven't come across any bugs. I don't know why you are using addEventListener here. To run a function on completion, you set the onComplete table entry. So in your case

gtween = GTween.new(sprite, 0.1, {x = 240}, {delay = 0.1 * i, 
ease = easing.outBounce, repeatCount = 1, reflect = true, onComplete=myfunction})

I also don't know why you are using gtween.dispatchEvents. I have never used this.

OZApps · August 2012

@alexzhang, I am surprised that you found GTween buggy, I have been using GTween not only for some of the pure gideros samples but also for the Compatibility layer and it works like a charm, even after adding eventListeners.

Though I had one question, if I nil the gtween handle, do I need to remove the eventListeners or would they automatically get removed as they are associated with the handle? To be on the safer side I do remove them, but Lua makes for some lazy programming, and this seems like work

OZApps · August 2012

for some reason the code you have looks fine but at the same time since you are overwriting the values of sprite and gtween it doesn't look right. Try to create an array and hold these values and see if there is any improvement.

alexzheng · August 2012

You have not noticed this bug just because you have not created enough gtweens at the same time.

And another situation is running multiple actions one by one on a sprite in short interval, it also will not work.

hnim · August 2012

@alexzheng: i think in your code, you run each action on difference sprite, not only one!?

OZApps · August 2012

You have not noticed this bug just because you have not created enough gtweens at the same time.

And another situation is running multiple actions one by one on a sprite in short interval, it also will not work.

That would enter the optimisation territory, where you would run one GTween and update the 100 items in the same tween as they all have the same tween applied. or have a central loop and modify each of the sprites accordingly, like a particle emitter.

and yes, maybe there is an issue with those many tweens thereby creating those many timers etc.

atilim · August 2012

When you specify a small duration (e.g. 0.01) and set "repeatCount = 1" and "reflect = true", "complete" event is not dispatched sometimes. And this bug exists with original GTween http://gskinner.com/libraries/gtween/ also. Because this bug also exists with original GTween, honestly I don't know how to fix it

I can recommend removing "repeatCount = 1, reflect = true" from your code.

Also from our previous discussion, this code works well:

local sprite = Bitmap.new(Texture.new("box.png"))
sprite:setAnchorPoint(0.5, 0.5)
stage:addChild(sprite)
 
local tween = nil
stage:addEventListener(Event.MOUSE_DOWN, function(e)
	if tween then
		tween:setPaused(true)
	end
	tween = GTween.new(sprite, 1, {x = e.x, y = e.y}, {ease = easing.outBounce})
end)

atilim · August 2012

@OZApps I usually don't remove any event listeners. When an object is GCed, all its event listeners are removed also.

alexzheng · August 2012

I can recommend removing "repeatCount = 1, reflect = true" from your code.

This trick works for this code
All boxes can move to the destination now.

local sprite
local gtween
local counter = 0
for i = 1, 100 do
sprite = Bitmap.new(Texture.new("box.png"))
stage:addChild(sprite)
 
gtween = GTween.new(sprite, 0.1, {x = 240}, {delay = 0.1 * i, ease = easing.outBounce, repeatCount = 1, reflect = true})
gtween:addEventListener("complete", function(data) counter = counter + 1 print(data, counter) end, i)
gtween.dispatchEvents = true
end

techdojo · August 2012

@OZApps I usually don't remove any event listeners. When an object is GCed, all its event listeners are removed also.

I'm with @OZApps on this one - I'm never sure exactly what's removed so I always make it a point to remove any event listeners manually (guess it's the C programmer in me

)

atilim · August 2012

Then I'll try to add removeAllEventListeners function as soon as possible as @nat12 suggested.

zvardin · August 2012

That would be great, although could it take a string as well, so we can remove all event listeners of a specific type also?

atilim · August 2012

@zvardin I was thinking exactly this way.

zvardin · August 2012

@atilim awesome!

OZApps · August 2012

@Atilim, removing the EventListeners based on a criteria would be nice. The criteria could be an Event Type, attached to an object. That would be really nice.

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