Cocos2D-X most efficient way to select the appropriate sprite sheet

Question

I have 3 sets of sprite sheets for my first scene. I'm using XCode to develop for iOS using Cocos2D-X.

The first sprite sheet has an extension -sd, the second sprite sheet has -hd, and the third set has 3 sprite sheets (using Multipack in Texture Packer Pro) with the extension -ipadhd. I followed a tutorial and I found a method that goes like this

CCString* file = (Utils::getArtScaleFactor() > 1) ? CCString::create("randomFile-hd.plist") : CCString::create("randomFile-sd.plist");

//The Utils::getArtScaleFactor function
float Utils::getArtScaleFactor()
{
    return artScaleFactor;
}

1- Is there a similar way to choose between 3 files instead of 2?

2- Is this the common method for choosing the appropriate file size-wise?

3- This question is somewhat off the topic I was discussing but I really need an answer to it too: I have an animation and its frames are split into 3 sprite sheets, how do I cache 3 .plist files? And if that's impossible, what are my options?

Hope I provided all the necessary information!

Regards

Answer 1

1. Sure, but that ternary operator should probably be switched out with another construct (like a switch) for clarity and flexibility.

   For example:

   // Always init your pointers.
   CCString* file = NULL;
   
   switch (Utils::getArtScaleFactor()) 
   {
     // Scale factor shouldn't ever be 0, but we should account for it 
     // so it doesn't get picked up by the default case.
     case 0:
     case 1:
       file = CCString::create("randomFile-sd.plist");
       break;
   
     case 2:
       file = CCString::create("randomFile-hd.plist");
       break;
   
     // Scale factors 3 and above get the largest resource.
     default:
       file = CCString::create("randomFile-super-hd.plist");
       break;
   }
   

2. Yes, this type of logic is on the wiki, except they use if-else for three resource sizes. I've seen it on the forums and tutorials, too.

3. According to this thread on the cocos2d-iphone forums, yes:

CCSprite can display CCSpriteFrames with different textures. So there’s no problem at all even to use animation that mixes frames from different textures (spritesheets) - Stepan Generalov

The implementations posted there are in obj-c but you can convert the cocos2d api calls to cpp easily.