A fast, easy to use, free, and community supported 2D game engine
sunshineDev
Member
Hi everyone,
I am having issues when I first load my sprites. I am using about 30 8bit PNGs. The problem is that the part of the application that uses Cocos2d is not the main view, it is contained within another view that loads after the user navigates to it.
The application behaves perfectly in the simulator, but when I go to test on the device, it takes a long time when I first navigate to it. After that, everything is fine.
Any ideas on what I can do to solve this issue?
Thanks in advance!
http://www.cocos2d-iphone.org/forum/topic/1237
Actually maybe some of this info should go on the wiki...
shadaz
Member
If your 30 sprites arent too big another solution might be to try using a sprite sheet, then its just loading 1 big image. If they dont fit on 1024x1024 you can also try to scale them down like 50% for the sheet, and then scale them up in the code. This has worked for me.
sunshineDev
Member
OK, I've been incorporating the addImageAsync to the texture manager and the problem I am running into is that I need a certain order in how the Sprites are added to the Scene. When I finally open my playing view everything looks out of whack. Any suggestions?
Thanks so much in advance!
Br0ken
Member
Not sure what the implementation of 'addImageAsync' is but if you're calling that for every one of the images you want to load then yes, I'm not suprised the order may not be right.
General rule of thumb when using Threads is that behaviour is never guaranteed. If job's A, B and C are started in that order job C could be given more time to complete than job A so it's possible job C will finish first.
If you need a specific order perhaps have an array of your image names, then iterate over the array calling 'addImageAsync' for each array element AFTER the previous 'addImageAsync' has completed.
sunshineDev
Member
Hi Br0ken, makes perfect sense. How can I know when addImageAsync has completed?
Should I use some kind of state variable that updates with "imageLoaded" and execute a sleep thread of sorts if the previous image is still not loaded? Is this a safe way to go?
Thanks.
sunshineDev
Member
The way this works is as follows:
[[TextureMgr sharedTextureMgr] addImageAsync:@"BackGrnd.png" target:mainViewController selector:@selector(imageLoaded:)];
Where imageLoaded is the callback.
For testing purposes I am only pre-loading one image which is the background and this is what I am doing in my callback:
-(void) imageLoaded: (Texture2D*) tex{
Sprite *bgSprite = [Sprite spriteWithTexture:tex];
CGSize size = [[Director sharedDirector] winSize];
bgSprite.position = ccp( size.width /2 , size.height/2 );
bgSprite.visible = YES;
Scene *scene = [[Director sharedDirector] runningScene];
[scene addChild:bgSprite];
}The final result here is that instead of showing me my background image, it is showing me a distorted version of the Cocos2d fps_images.png. If I do this same procedure in a synchronous fashion it works perfectly. What am I doing wrong?
Br0ken
Member
Any chance you can put your code into a demo Xcode project for us to see for ourselves? Sometimes these bugs are really difficult to solve without having experienced them and/or seeing the complete code.
But from the code snippet above I don't see anything that is obvious which would cause that problem.
sunshineDev
Member
Hi Br0ken, I think I found my answer.
Since I attach the Director to a different view from the main Window to which the user navigates only if they want to, and I was loading my images on Application Startup, I was loading my scene before I attached my Director to any view. Apparently this shouldn't be done this way, I found it in another thread:
http://www.cocos2d-iphone.org/forum/topic/2143#post-13448
I think it might be working now, I only have to figure out how to get them in order :)
I truly appreciate all your help.
Br0ken
Member
Thats great, nice one!
As for the original problem, if you have to have things done in a set order you've inherently got something synchronous there.
What you could try is spawn a thread that deals with the whole preload of images. Ie.
A new thread starts, in the method that is run on that thread you loop through an array of images, loading them one at a time.
The images will be loaded in order of the array elements but the thread is a background task.
If your user navigates to the view before all images have been loaded you can show a loading screen and the thread will carry on in the background loading the images.
Br0ken
Member
I don't know Cocos2D in depth I'll admit but I can't see why that wouldn't work. I know that if you do drawing and variable updates in the wrong place you can experience unexpected results but loading images into memory on a background thread, I shouldn't think that would cause problems.
Only one way to find out I guess.
Alternatively, we've ignored something else; what images are you loading that you need to be loaded in a particular order? And why?
sunshineDev
Member
I have two separate reasons:
Thanks for all your help, I truly appreciate it.
Br0ken
Member
No problem, one of the ways I learn is by trying to help with other peoples issues. Learning from a book is easy because the code is always supposed to just work, but learning from tricky real world issues helps me more.
With regards to your points;
Point 1: You could use an AtlasSprite instead for animation? That way you're loading just one (larger) image?
Point 2: You could add an extra layer to your scene for the container image that is above the layer which has the liquid?
sunshineDev
Member
That is an excellent way to learn, where do you find the time though?!
Point 1: You could use an AtlasSprite instead for animation? That way you're loading just one (larger) image?
This might be a possibility that I will look into. I think the major issue here is positioning, given that my images are just parts of the scene inside a PNG which is the size of the scene (does this make sense?) This is the only way I could place them in the scene and know that they were going to be in the correct spot.
Point 2: You could add an extra layer to your scene for the container image that is above the layer which has the liquid?
This one is more tricky because the way the graphic designer gave them to me is in layers with different blend modes. In order for the liquid to show up I have to render these exactly.
Thanks again.
Br0ken
Member
That is an excellent way to learn, where do you find the time though?!
Easy, don't sleep :P
This might be a possibility that I will look into. I think the major issue here is positioning, given that my images are just parts of the scene inside a PNG which is the size of the scene (does this make sense?) This is the only way I could place them in the scene and know that they were going to be in the correct spot.
Sorry I don't understand lol...?
This one is more tricky because the way the graphic designer gave them to me is in layers with different blend modes. In order for the liquid to show up I have to render these exactly.
I still don't see why you cannot use Layers in Cocos2D?
Posting a demo app might help? If you're worried about some one stealing the images maybe email it instead?
sunshineDev
Member
He he he he!
With regards to the AtlasSprite, I haven't used it in the past. My images are all PNG's the same size as my background PNG. Each of the images have an object and the rest is transparent background. For example, one is a table and the other one is a bowl but both files are the same rectangular size just with transparent backgrounds. Does this make sense?
I did it like this because it was the best way I could find to place my objects exactly where I wanted to and I don't know if I can do this with an AtlasSprite.
With regards to layers, I don't think I'm understanding correctly. I have many different Sprites stacked up on top of each other, some with their own blend modes (Screen, Multiply, etc) to be able to give the same effect as the original graphic had in Photoshop. It must be this way, I can't join them all together in one graphic. You think that if I group them in one layer I can achieve this?
Thanks
Br0ken
Member
With regards to the AtlasSprite, I haven't used it in the past. My images are all PNG's the same size as my background PNG. Each of the images have an object and the rest is transparent background. For example, one is a table and the other one is a bowl but both files are the same rectangular size just with transparent backgrounds. Does this make sense?
I did it like this because it was the best way I could find to place my objects exactly where I wanted to and I don't know if I can do this with an AtlasSprite.
I understand. So those objects (table/bowl) could be the animated parts? If so I don't think this is a good approach. Read this interesting topic about memory (remember you're an a mobile device, be conscious about your memory usage) http://www.cocos2d-iphone.org/forum/topic/3112. Personally I would have sprites for the object itself and workout the co-ordinates to place them, it's not very hard.
With regards to layers, I don't think I'm understanding correctly. I have many different Sprites stacked up on top of each other, some with their own blend modes (Screen, Multiply, etc) to be able to give the same effect as the original graphic had in Photoshop. It must be this way, I can't join them all together in one graphic. You think that if I group them in one layer I can achieve this?
Yes, just like in Photoshop where you have layers for your image you can put layers on the scene. There's an overloaded add method where you can supply a 'Z-depth' value. So your liquid can be added at z=0 and your container added as z=1. The container layer will overlap the liquid layer. Hope that's made sense.
ps. Use layers sparingly too for performance.
sunshineDev
Member
So you would suggest having those objects as Sprites but also having the animation transitions be in an AtlasSprite?
For example, if I had a liquid rising animation I would have an AtlasSprite for the different liquid levels (only for the liquid, not a transparent rectangle for the whole scene).
Would this be a better approach?
sunshineDev
Member
Hahahaha! I wish...
I think I might run into a snag with AtlasSprites, I think I recall reading that it doesn't support blend modes. I'll have to look it up an see. If this is the case, I have 2 options but I don't know which one would be better.
This is my scenario: I have a glass container with liquid inside. Imagine that this liquid is the only animated element. Ironically I decided to use separate Sprites for the container and the liquid for possible memory issues. Given this scenario, I have 2 options:
Which one would be wiser?
You must log in to post.