A fast, easy to use, free, and community supported 2D game engine
regner
Member
I have class that draws and handles animated sprite.
In my game i need to have thousands of those sprites.
I've read that it is good thing to create your nodes in "init" method, but isn't that a terrible waste of memory, if i see only small portion of those sprites at a time?
I was thinking of creating only sprites i see at the moment, and releasing them when they are off screen.
Is that a good idea or there is some other way to handle this?
Questor
Member
regner,
Creating/Reading/Building resources is generally expensive, which is why the general rule of thumb is to create all of them (or as many as is reasonable) at game start because you've got a loading screen and a few extra seconds at startup is easier for a user to handle than stuttering gameplay performance.
However, that rule is not absolute. If you are using only a handful of sprites at a time, then you might be better off into looking into re-using those sprites as much as possible. Don't destroy them completely, just flag them as dead and move them off screen (or hide them) until you need them again. People often do this with common enemies (or even bullets) as they need to destroy and create them throughout gameplay....so reusing them is more efficient.
Every game has it's own needs and performance and memory usage is always a trade-off. For your game, I would create slightly more than you could ever need on screen at one time and then re-use as much as possible. However, you are still probably going to need to do some creation and destruction...
Ultimately, if your program stays under the memory limitations and the speed is good, you may very well decide to trade-off memory/CPU efficiency with simplicity of design. And as you said, in your case, generating thousands of sprites when you will only ever need a handful does not make sense... So reuse is an option...but so is creating them and destroying them if it allows your game to be of a simpler design (and of course, does not adversely affect gameplay).
Hope this helps.
Regards,
Q
robodude666
Member
While you do have the lovely loading screen to give you a bit of time to cleanup, you should try to minimize the load time as much as possible.
The iOS (that includes older versions of the iPhone OS) have a watchdog timer. This timer will terminate your application of certain checkpoints aren't reached. If your application fails to respond from the applicationDidFinishLaunching within 10 seconds, failed to quit within 6 seconds of the user asking it to, or failed to resume after 10 seconds from being backgrounded the iOS will terminate your application.
In the WWDC2010 session videos, available on iTunes U, were a number of great sessions regarding optimizing for performance.
Two of the things they did were to:
- Cut time from the startup time
and
- Reuse TableView cells that are no longer active
You should try to do something similar if you can. For example, at startup ONLY load the things that you know will be needed. The menu sprites, hero sprites, sound effects, etc. But try to keep it low. If you're developing for the iOS 4 then checkout some of the Grand Central Dispatch abilities.
Then as Questor mentioned reuse sprites. If a sprite object has been "killed" or if a bullet is no longer valid, instead of destroying it from the world and deleting the object put it into a "queue" where it will live. Later on, when you want to create a new bullet check to see if any bullets exist in the queue. If there is return one of them. Otherwise, allocate memory for a new one.
This will reduce memory spikes which can sometimes create false positives that might make the iOS trigger a memory warning, as well as increase performance as creating new objects can be expensive.
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