My preference would be to use Texture Packer, so I found extracting the Atlas stuff from the C++ runtime a bit tricky. I would be interested to see how you integrated it with obj-c though. I looked at it, and couldn't see a clean way.

I figured it would only take a few hours to re-write the runtime in obj-c ....

Sounds like my obj-c implementation has some merit then. The apple libraries read JSON data into an NSDictionary, so I am trying to feed that data nicely into the front end at the moment. I have converted a number of classes already, but if you have any guidance on the changes needed for the c++ runtime where it deals with the atlas, I will gladly accept the help

Edit:
Got to be said, some comments wouldn't have gone amiss in these runtimes lol - especially the skin stuff ! very confusing. My rudimentary C++ is letting me down

Having lots of trouble extracting the JSON skin data, as none of it is keyed

getting the bones and slots like this:

       NSArray *attachments = [SkeletonJSON objectForKey:@"bones"];
        for(NSDictionary *object in attachments) {
            NSLog(@"%@", [object objectForKey:@"name"]);
            NSLog(@"%@", [object objectForKey:@"parent"]);
            NSLog(@"%@", [object objectForKey:@"length"]);
            NSLog(@"%@", [object objectForKey:@"x"]);
            NSLog(@"%@", [object objectForKey:@"y"]);
            NSLog(@"%@", [object objectForKey:@"scaleX"]);
            NSLog(@"%@", [object objectForKey:@"scaleY"]);
            NSLog(@"%@", [object objectForKey:@"rotation"]);
        }
        

    NSArray *attachments1 = [SkeletonJSON objectForKey:@"slots"];
    for(NSDictionary *object in attachments1) {
        NSLog(@"%@", [object objectForKey:@"name"]);
        NSLog(@"%@", [object objectForKey:@"bone"]);
        NSLog(@"%@", [object objectForKey:@"color"]);
        NSLog(@"%@", [object objectForKey:@"attachment"]);
    }

Finally (after much trial and error) getting the skin info using this code, although it doesn't seem so intuitive ..... (plus I don't have a Spine export with an attachment 'type', so not reading that yet)

        NSDictionary *skinNames = [SkeletonJSON objectForKey:@"skins"];
        NSArray*keys=[skinNames allKeys];
        for (int i=0; i<[keys count]; i++) {
            NSLog(@"Skin %@",keys[i]);
            NSDictionary *slotNames = [skinNames objectForKey:keys[i]];
            NSArray*keys1=[slotNames allKeys];
            for (int ii=0; ii<[keys1 count]; ii++) {
                NSDictionary *attachmentNames = [slotNames objectForKey:keys1[ii]];
                NSLog(@"Slot %@",keys1[ii]);
                NSArray*keys2=[attachmentNames allKeys];
                for (int iii=0; iii<[keys2 count]; iii++) {
                    NSLog(@"Attachment %@",keys2[iii]);
                    NSDictionary *attachments2 = [attachmentNames objectForKey:keys2[iii]];
                        NSLog(@"%@", [attachments2 objectForKey:@"x"]);
                        NSLog(@"%@", [attachments2 objectForKey:@"y"]);
                        NSLog(@"%@", [attachments2 objectForKey:@"scaleX"]);
                        NSLog(@"%@", [attachments2 objectForKey:@"scaleY"]);
                        NSLog(@"%@", [attachments2 objectForKey:@"rotation"]);
                        NSLog(@"%@", [attachments2 objectForKey:@"width"]);
                        NSLog(@"%@", [attachments2 objectForKey:@"height"]);
                }
            }
        }

yeah thats pretty much what I have in the NSDictionary, so my processing loops are correct. thanks for validating that. Just trying to keep it all as neat as I can.

I'm just doing this because I like to understand the detail, and using my own rendering engine I can get some really good speed, which means more objects on the screen animating at once. I'm not taking anything away from the cpp runtime, as I'm sure its fine. However, it wasn't put together in an end to end iOS or Android example, so that means we have to make it work with our own workflows we have set up. One size doesn't fit all.

@authbattkledamage sorry, not sure about working with someone else though, as I can only really drop in and out as I get time.

Ahh thanks for the class diagram, it really does help. I have no idea whether what I am doing will be better or not, I just eventually want to get as much of the processing into a shader as possible and free up the CPU. I am hoping to get the animation into a vertex shader eventually. Once I have worked out all the details. One step at a time though

Little progress update, Skeleton Data now all reads in using obj-c runtime. Just gotta tie things all up and see if something draws now ... (no animation yet, as I haven't loaded that data yet)

Hmm, something not quite right, although at least its all in obj-c . Can't see where I'm going wrong at the moment. Does Spine assume images rotate from the centre, and their x/y coordinates are in the centre too ? Not that offsetting them by widths/heights seems to make any difference at the moment.

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