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ob1
Member
Hi,
I was wondering how to do a loading bar.
A few options I have considered are:
- A small uniform bar and modify x scale at each step but apparently cocos strangely doesn't allow X and Y to have different scales.
- Use an AtlasSpriteManager and somehow change the texture rectangle at each step (setDisplayframe ?) according to load %
- Make an animation with a frame for each step.
Any opinion ?
ob1
Member
Hmmm I was referring to this about the scaling:
-(float) scale
{
if( scaleX_ == scaleY_)
return scaleX_;
else
[NSException raise:@"CocosNode scale:" format:@"scaleX is different from scaleY"];
return 0;
}
-(void) setScale:(float) s
{
scaleX_ = scaleY_ = s;
isTransformDirty_ = isInverseDirty_ = YES;
}I like the first idea because I probably don't have 10% percents of progress (more like 50 steps) although I could round to tenth.
But Codemattic's idea probably looks better. I will think about it.
Steve Oldmeadow
Administrator
There is also ColorLayer (buried away in Layer.h). It is basically a colored rectangle that can have its dimensions varied.
Steve Oldmeadow
Administrator
ColorLayer looks good if you put an overlay image on top with a transparent portion for the progress to show through. Also you can create some interesting effects with some minor hacking to allow different colors for vertices since OpenGL ES will blend between the colors.
ob1
Member
I have another question in fact. What is the best way to load the files and update the bar ?
Launch a time load scheduler and a periodic bar update scheduler ?
Load each file asynchronously and have a delegate called after each load that updates the counter and loads the next file?
The link in this thread will help.
http://www.cocos2d-iphone.org/forum/topic/280
ob1
Member
Yeah I saw it, but it looks like a hack that uses the fact that Cocos and UIKit run in a different thread.
I have a huge problem right now. I put my load code in a separate thread and I create an autorelease pool at the beginning. However my app crashes for an unknown reason. I looked with the debugger, and any autorelease object that I create is apprently immeditaley released even before I can use it.
Any hints about what is happening ?
Well you can use that code and not use the UIKit part. It's just a loading scene that you can add steps to perform all your loading. Each step you can update your loading graphic. I used it as a baseline but i don't have any loading animations yet. It's on my list of things to do though.
ob1
Member
Ok, the problem was not what I thought at all (I was fooled by debugger's artefacts).
It seems it is not possible to load textures from another thread, the gl* calls crash with bad access.
Did I do something wrong or is it impossible to load textures from a second thread ?
It is possible..
NSAutoreleasePool *autoreleasepool = [[NSAutoreleasePool alloc] init];
//Create a shared opengl context so this texture can be shared with main context
EAGLContext *k_context = [[[EAGLContext alloc]
initWithAPI :kEAGLRenderingAPIOpenGLES1
sharegroup:[[[[Director sharedDirector] openGLView] context] sharegroup]] autorelease];
[EAGLContext setCurrentContext:k_context];
[self doPreloadLevel];
[autoreleasepool release];
Where it says [self doPreloadLevel], load your stuff.
errr....
NSAutoreleasePool *autoreleasepool = [[NSAutoreleasePool alloc] init];
//Create a shared opengl context so this texture can be shared with main context
EAGLContext *k_context = [[[EAGLContext alloc]
initWithAPI:kEAGLRenderingAPIOpenGLES1
sharegroup:[[[[Director sharedDirector] openGLView] context] sharegroup]] autorelease];
[EAGLContext setCurrentContext:k_context];
[self doPreloadLevel];
[autoreleasepool release];
ob1
Member
@Joao: Worked like a charm. Thanks a lot!
@clain: How did you change the frame of your sprite ? If I just do something like :
[sprite setDisplayFrame:[AtlasSpriteFrame framewithRect:...]
the original texture gets distorted instead of getting another part of the sprite manager like in your picture. Did you have to make an animation ?
Here is how I change the frame of my sprite :
CGRect texRect = CGRectMake( (barPngWidth/2)*(1-loadPercentage), 0, barPngWidth/2, barPngHeight);
[barAtlasSprite setTextureRect:textRect];
My loadPercentage var should be comprised between 0 and 1. You definitely don't have to use an animation nor the setDisplayFrame function.
I'll add a async method to load images in v0.8.
In my repository I have a version that uses performSelectorOnMainThread but it doesn't work well, so I'll use thread
r1067 supports image async loading.
See Texture2dtest.m to see how to use it
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