How to convert .json from Spine3.6.xx to 3.1.xx?

wangyin215

Hi,

Our Spine files (json, atlas, png) in our app have been prepared using Spine 3.6.50. But from the app perspective, we used the older version of cocos2dx engine(cocos2dx 2.2.3). I notice that the lastest runtime version for cocos2dx 2.2.3 is in the branch - cocos2dx-v2, and the Readme file said "spine-cocos2dx v2 works with data exported from Spine 3.1.08."

Unfortunately, we have done a lot of animations in spine 3.6.50. So i want to convert the .json(exported from 3.6.50) to .json(can be imported by 3.1.08).

I did the attempt step by step(copy content to .json and try to import), and found that:

3.1.08 can use the "bones" section
3.1.08 can use the "slots" section
but in skins section, when i edited the following code to the json(exported from 3.6.50), spine 3.1.08 will imported error.
"skins": {
"default": {
"finger": {
"finger": {
"type": "mesh",
"uvs": [ 0.14206, 0.01496, 0.03123, 0.02052, 0.02173, 0.18734, 0.16106, 0.32081, 0.40806, 0.44685, 0.47456, 0.673, 0.66139, 0.99924, 0.94956, 0.99924, 1, 0.825, 0.86406, 0.59144, 0.76273, 0.3412, 0.47773, 0.19291, 0.16086, 0.16132, 0.3857, 0.27439, 0.58836, 0.37264, 0.69919, 0.6099, 0.8227, 0.87312 ],
"triangles": [ 2, 12, 3, 2, 1, 12, 1, 0, 12, 11, 12, 0, 3, 13, 4, 4, 13, 14, 13, 11, 14, 3, 12, 13, 13, 12, 11, 6, 16, 7, 7, 16, 8, 6, 15, 16, 6, 5, 15, 16, 9, 8, 16, 15, 9, 5, 14, 15, 5, 4, 14, 15, 10, 9, 15, 14, 10, 14, 11, 10 ],
"vertices": [ 1, 10, 8.88, -2.21, 1, 1, 10, 10.4, -0.01, 1, 2, 9, 14.24, 4.43, 0.01579, 10, 5.27, 4.52, 0.98421, 2, 9, 7.9, 5.44, 0.7013, 10, -1.08, 5.42, 0.2987, 2, 8, 16.05, 3.96, 0.61124, 9, 0.12, 4.28, 0.38876, 1, 8, 6.71, 5.02, 1, 1, 8, -7.39, 4.45, 1, 1, 8, -9.32, -2.19, 1, 1, 8, -2.8, -5.35, 1, 1, 8, 7.3, -4.89, 1, 2, 8, 17.83, -5.43, 0.84921, 9, -2.11, -5, 0.15079, 2, 9, 6.96, -3.75, 0.91487, 10, -1.87, -3.78, 0.08513, 2, 9, 12.88, 1.19, 6.3E-4, 10, 3.96, 1.26, 0.99937, 2, 9, 5.85, 0.1, 0.99992, 10, -3.05, 0.05, 8.0E-5, 2, 8, 17.77, -1.05, 0.77272, 9, -0.37, -0.98, 0.22728, 1, 8, 7.68, -0.88, 1, 1, 8, -3.51, -0.71, 1 ],
"hull": 12,
"edges": [ 0, 2, 2, 4, 4, 6, 6, 8, 8, 10, 10, 12, 12, 14, 14, 16, 16, 18, 18, 20, 20, 22, 0, 22, 2, 24, 24, 26, 26, 28, 28, 30, 30, 32 ],
"width": 24,
"height": 41
}
}
}
},

so, i use spine 3.1.08 to make a mesh, then export, the json like this, and works fine:
"skins": {
"default": {
"body": {
"body": { "x": 35.14, "y": -2.91, "rotation": 91.3, "width": 209, "height": 142 }
},
"head": {
"head": {
"type": "mesh",
"uvs": [ 0, 0, 0.20726, 1.0E-5, 0.40726, 0, 0.6, 0, 0.8, 0, 1, 0, 1, 0.2, 1, 0.4, 1, 0.6, 1, 0.8, 1, 1, 0.8, 1, 0.6, 1, 0.4, 1, 0.2, 1, 0, 1, 0, 0.8, 0, 0.6, 0, 0.4, 0, 0.2, 0.2, 0.2, 0.2, 0.4, 0.2, 0.6, 0.2, 0.8, 0.4, 0.2, 0.4, 0.4, 0.4, 0.6, 0.4, 0.8, 0.6, 0.2, 0.6, 0.4, 0.6, 0.6, 0.6, 0.8, 0.8, 0.2, 0.8, 0.4, 0.8, 0.6, 0.8, 0.8 ],
"triangles": [ 20, 19, 0, 1, 20, 0, 24, 1, 2, 20, 1, 24, 28, 3, 4, 2, 3, 28, 24, 2, 28, 32, 4, 5, 28, 4, 32, 32, 5, 6, 18, 19, 20, 21, 20, 24, 18, 20, 21, 25, 24, 28, 21, 24, 25, 29, 28, 32, 25, 28, 29, 33, 32, 6, 29, 32, 33, 33, 6, 7, 17, 18, 21, 22, 21, 25, 17, 21, 22, 26, 25, 29, 22, 25, 26, 30, 29, 33, 26, 29, 30, 34, 33, 7, 30, 33, 34, 34, 7, 8, 16, 17, 22, 23, 22, 26, 16, 22, 23, 27, 26, 30, 23, 26, 27, 31, 30, 34, 27, 30, 31, 35, 34, 8, 31, 34, 35, 35, 8, 9, 15, 16, 23, 14, 23, 27, 15, 23, 14, 13, 27, 31, 14, 27, 13, 12, 31, 35, 13, 31, 12, 11, 35, 9, 12, 35, 11, 11, 9, 10 ],
"vertices": [ 168.54, 88.94, 168.15, 54.12, 167.78, 20.52, 167.42, -11.84, 167.05, -45.44, 166.68, -79.04, 133.08, -78.67, 99.48, -78.29, 65.87999, -77.92, 32.28, -77.55, -1.29999, -77.17, -0.93, -43.58, -0.56, -9.97999, -0.18, 23.61, 0.18, 57.21, 0.55, 90.81, 34.15, 90.43, 67.75, 90.06, 101.35, 89.69, 134.94, 89.31, 134.57, 55.71, 100.97, 56.09, 67.37, 56.46, 33.78, 56.83, 134.2, 22.12, 100.6, 22.49, 67, 22.86, 33.4, 23.24, 133.82, -11.47, 100.23, -11.1, 66.62999, -10.72, 33.03, -10.35, 133.45, -45.07, 99.85, -44.7, 66.26, -44.32, 32.66, -43.95 ],
"hull": 20,
"edges": [ 0, 2, 2, 4, 4, 6, 6, 8, 8, 10, 10, 12, 12, 14, 14, 16, 16, 18, 18, 20, 20, 22, 22, 24, 24, 26, 26, 28, 28, 30, 30, 32, 32, 34, 34, 36, 36, 38, 38, 0 ],
"width": 168,
"height": 168
}
}
}
},

I cannot find why 3.1.08 cannot use the "finger" mesh. I think may be there are some different algorithm about the "triangles" or "vertices" in the in 3.6.xx version.

So my questions are:

Is it possible to convert Spine files (json, atlas, png) from spine 3.6.50 to make them support the Spine 3.1.08?
What's the details when doing the convert?
What's are best practices for my situation?

Thanks in advance for any hints.

Nate

Sorry you are having trouble. After some digging, back in 3.1 there were mesh and weightedmesh attachment types. Later, all meshes use the type mesh. When you want to go back to 3.1, you need to change "type": "mesh" to "type": "weightedmesh" for meshes that are weighted to multiple bones.

wangyin215

@Nate, Thanks for your reply.

For this situation, we have a new idea. Can we refer to the official cocos2dx v3.6 example, to write an implementation for cocos2dx v2.2.3, let cocos2dx v2.2.3 support our spine3.6.50 export. Because we have no development experience in this part, would like to ask how difficult this realization is? if it is an impossible task(such as cocos2dx 2.2.3 cannot support some features)?

Thanks again, hoping to give any hints to me.

Nate

A newer version of Spine most likely has features that can't be supported in an old runtime. Eg, 3.6 has clipping attachments while 3.1 doesn't. It would be best to export to JSON, modify the JSON so it can be imported into the 3.1 editor, then use the 3.1 editor.

You can try the JsonRollback tool. It is intended to go from 3.4 to 3.3, but it may help.
Spine editor and runtime version management

The source is Java and can be found here:
spine-runtimes/JsonRollback.java at 3.6
You could also edit it to do more, like change mesh to weightmesh if the mesh has weights. To know if a mesh has weights, check if the number of vertices is equals to vertexCount * 2:

boolean hasWeights = mesh.getInt("vertexCount") * 2 != mesh.get("vertices").size;

Edit: Actually, I exported from 3.6 (I used spineboy-pro with the transform constraints deleted, which has both meshes and weighted meshes), processed it with JsonRollback, then imported into 3.1 just fine. So, likely you can just apply JsonRollback to all your JSON files, then import them into 3.1. We don't yet have importing JSON to a project file on the command line, so unfortunately you'll have to manually do an import for each JSON file.

wangyin215

@Nate, Thank you very much, you saved my life : D
Although some of our animations have some mistakes, we can recover them with a few minor changes.
Thanks again to spine team for timely support and help.