I'm working on a program in Flash coded in Actionscript 3 and I'm trying to determine if I should remove MovieClips from the stage when they're not on screen, or just stop moving them once they're outside the viewing area. If I do not removeChild() the MovieClips once they move out of the viewing area, I can potentially end up with tens of thousands of MovieClips on the stage (though not in view).
Is there a standard recommendation for hiding vs. removing MovieClips when not in view?
Basically, I'm trying to find out:
Does having MovieClips on the stage but outside of the viewing area use a lot of resources?
How much of a penalty does removing and adding MovieClips to and from the stage incur?
Is there an estimate of how many MovieClips you are working with before you should switch from one method to the other?
Thanks!
--EDIT--
In my program, MovieClips will often have to reappear on the screen. This means that when I remove them from the stage, they might have to be added back. If I hide them off-screen, they might have to be moved back on-screen. This is why I don't just removeChild() everything and null out the object.
Does having MovieClips on the stage but outside of the viewing area
use a lot of resources?
Your MovieClip uses the same amount of memory whether it is inside or outside of the viewing area.
How much of a penalty does removing and adding MovieClips to and from
the stage incur?
Removing/nulling is cheap, creating new object is much more expensive.
Is there an estimate of how many MovieClips you are working with
before you should switch from one method to the other?
If you are dealing with hundreds or thousands of instances have a look into object pooling.
There is also a nice video tutorial about object pooling. It is worth watching if you want to know more about destroying/creating display objects.
If you do not intend to reuse the movieclips, you should definitely remove them. The action is costless and it frees the memory of your movieclip. Having a hidden movieclip uses the same amount of memory, it is just easier on the display process (your application won't lag but this is a major memory leak).
It's a good idea to remove them if they are not being used. If it's an item that moves (say at an x speed of 5px/s), even once it's left the screen the item is still being processed and is moving farther and farther away.
Basically if it's not in use and serves no purpose then remove it to save on resources.
Related
Good evening/ morning.
I am creating a game in As3 where the enemies are added not added dynamically.
if(hero attacks enemy)
{ then parent.removeChild(enemy) }
When the hero attacks the enemy the enemy removes it self from the display list I presume.
but when you reset the level, i.e go back to the start menu and go back to the level you will see the enemies are not in the level, since they've been removed.
My question is, is there a way I can reset the display object in that frame, in As2 I refreshed the flash movie. But that's not good in terms of coding as it shows you are not developing or learning.
IF there is no way, will you suggest adding the objects that will be removed, dynamically?
another question is that my level is in a container.
//on the stage, there is a movieclip called container.
//In this container mc(movie clip) it contains the whole level, including platforms,
//enemies and props
IF I remove a prop from that container, in order to reset the game will I do this
container.addChild(prop)
//the question is that how do I set it's x and y position?
Thank you, I will appreciate every ones feedback and advice.
Yes, as you remove them dynamically, you need to add them dynamically again in order to reset them. You either predefine their positions and set them again, or you can just hide those enemies and make them visible once again the game resets. Depends on your code and structure.
Ideally, instead of removing them from the display list, your best bet is to hide then and put them and reset their position back to their original point.
A good practice to get into is to avoid the chance of runaway instantiation if at all possible; this means, if you're going to instantiate and remove enemies every time they're spawned and killed, the garbage collector has to work very hard to keep up. A better approach would be to have a pool of enemies that is as large enough to support as many enemies as you would ever need at one time.
I have many small, identical vector circles that move around the screen, but only appear for a defined period in defined areas. Currently, these circles are children of whatever parent object produces them, and each is given its own interframe handler for animation (move a few pixels, maybe change alpha). With hundreds on screen, this gets somewhat slow.
Would it be advisable to cache the circles as bitmaps? Would it be better to add them all to one array and have one interframe event handler run through the whole shebang, even if up to 90% aren't being animated in a specific frame?
Would it be faster to cache one circle as a bitmap and set all others to use the first shape's bitmapdata? Would it be even better to use a "CopyPixel" approach to erase and redraw ("blit") every circle at its new position every frame? I hear conflicting reports of the usefulness of CopyPixel on large mobile device canvases...
If the animation can be looped make a movie from the movie else try everything you can. Usually a CopyPixel approach is faster but I wouldn't expect much. I don't think it pays the bill either hence reduce the numbers of circles.
I'm making a flash game, and I can't decide to use a bigger stage or a smaller one, with scrolling background to make it run smoother. I's going to be some kind of strategy game if it matters.
Thanks
One option is to have a bitmap object the size of your stage for example 800x600, then draw your objects into the bitmapdata of that bitmap using copyPixels this is known as blitting and is pretty fast.
Another option is to just use the flash display list and add every object as sprites onto the stage.
Second method is easier to handle in terms of mouse events and stuff.
My advice is to start with the second option and see if performance is enough, if not go with option 1.
There are many, many variables that determine the performance of your application.
To answer your question, a smaller stage area will make your program run faster. The amount of difference will depend on the way your application deals with display objects. Flash will not render things that are completely outside the stage bounds. So keeping only those objects that are needed at any given time on the stage is a good practice.
using flash player 11's new stage3D features (even for 2D stuff) will likely make your game very smooth. Lots of good frameworks out there that can take care of the low-level stuff if you don't want to get into it. For 2D, starling is very easy to get started with, and seems to be Adobe's favored framework.
At a bare minimum, make sure you use GPU acceleration in your output/compiler options.
There are LOTS of other tips for optimization people could get into, but that is better suited for google searches as Stackoverflow is about specific questions.
I already know all the problems in programming based on timeline, but I'm curious to know what happens to garbage collector in that situation.
Talking about code in timeline - as a movieclip isn't accessible if the code isn't in the same frame as it, does this raises the possibility of memory leak?
Seems to me that the movieclips in timeline are added when the "playhead" currently is on it's frame, and removed when it goes out.
The Garbage Collector will not be able to clean/dispose a movie clip removed from stage if:
that clip is still playing and does stuff (create/remove other things...)
that clip is still referenced by some other instance that is "reachable"
you try to remove a way too complicated hierarchy containing too many items [I dont have any number for this, but I'd guess around 2^32 items?]
One way I usually use to see if there is a memory leak is to run SWF Profiler in FlashDevelop and force GC to run at certain situations and see what gets deleted.
Please check following article for more information:
http://active.tutsplus.com/tutorials/workflow/quick-tip-understanding-garbage-collection-in-as3/
The code is still apart of that MovieClip. So it is still there. And since the MovieClip is presumed still attached to its parent then it stays.
(I say attached to its parent instead of on screen, because its possible to have parent reference the child, and the child references the parent with the .parent variable, so since they both have something pointing to them, they stay in memory).
I am working on a project that will have the user seeming to fly in 3D from point to point in an architectural model, based on choices. It is a tree-flow, with everything starting from one point and branching out from there, and it only needs to animate in one direction, which makes things easier.
The thing is that the animations from place to place are C4D animations rendered as PNG sequences, and in total they will be VERY large, so I want to package each segment as an individual SWF and load and unload them dynamically as needed.
I expect the first thing to do will be to see if I can have my upstream guy render them as JPG sequences instead... is that a good idea performance-wise? I imagine it will be in terms of bandwidth.
The main question, however, is how I can dynamically load one of these sequences, have it play and stop on its final frame (over which data and choices will display), and then - based on the user's selection - load and play the next animation seamlessly from the first, without endlessly stacking up loaded clips. When the user goes back a level, I only need to jump to the first frame of the animation, but going forward always involves a smooth flight.
I suspect the solution may have to do with adding, say, to the loader by specific names, then as we transition out, load the next one with a specific name, and then unloadChild() and do whatever other kind of garbage collection I need to do to purge from memory entirely. I want to be as cognizant of memory usage and performance as I can, because at certain spots there will be other images and videos loaded on top of the flight animations.
Does anyone have any ideas about this? I'm sure it's a common need, I've just never done it before, and I want to do this as timeline-free as possible.
Thanks in advance for any advice!
Mattynabib