Getting an attachment's position

ArvoAnimi

Hi guys, been looking for this and can't quite find it in the forum so far.

We've got a spine file in unity where the spine hierarchy goes like this
bone-slot-skin-attachment

we need to get the attachment's position relative to the bone at runtime, is there any easy way to do this? if not, can this be a request?
Might be just me, but it seems like something coders would want easy access to.

Thanks in advance, and keep it up, spine is an amazing tool!

Mario.

Nate

RegionAttachment has an offset SRT which is the center of the attached region.

ArvoAnimi

Ok, I was on the right track, is there any reason why this would not work then?

Again the hierarchy in spine goes like this: Slot/skin/attachment

Spine.RegionAttachment attchmnt = (Spine.RegionAttachment)mySkeletonAnimation.skeleton.GetAttachment("slotname", "attachmentName");

Then I could use

attchmnt.X and attachmnt.Y

Is this right? cause it ain't working for me.

And it looks like the problem here is the cast to regionattachment, is it normal that a cast from an attachment to a regionattachment fails?

Further reading on the documentation lead me to think that regionattachment are accessible only when creating a new attachment, in my case the attachment already exists, it's not being loaded/created... any way to get the attachment's position in this case?

To be precise the problem I'm having is that the bones are not animated at all in here, we use the slots to hold skins, and swap skins to reposition meshes, which have different positions(ffd offsets) in each skin.
My problem is getting the offset or position of the mesh in this hierarchy.
bone/slot/skin/mesh

So I guess that what I would need... finally... is to get the vertex information for that mesh... with that the position could be averaged or something... anyway, it all leads to regionattachment again.

Nate

ArvoAnimi ha scritto
cause it ain't working for me

It isn't clear what your actual problem is. If you get an exception, please post the exception. If the attachment is not a RegionAttachment, what is it? It could be a BoundingBox, MeshAttachment, or SkinnedMeshAttachment.

Pharan

ArvoAnimi ha scritto
is it normal that a cast from an attachment to a regionattachment fails?

What do you mean by "fails"? Didn't it log something useful?

ArvoAnimi

When I try to cast it to RegionAttachment i get
InvalidCastException: Cannot cast from source type to destination type.
And I am sure it is a mesh using ffd

Ok let me try to ask the right question here.

I got an attachment, it's a mesh that uses ffd and I'm trying to get to it on runtime by doing this:

mySkeletonAnimation.skeleton.GetAttachment("slotname", "attachmentName");

That part works fine, I've got the attachment reference, now, how can I get to it's regionattachment? there's no access to it from the Attachment class.

Common sense for me would be something like attachment.regionAttachment but there's no such thing. What I need is access to the RegionAttachment on runtime so I can check it's mesh information at any given moment.

Thanks, and sorry if I wasn't clear before.

Pharan

The docs are really out of date regarding attachments.
As Nate mentioned, there are at least four types of Attachments. RegionAttachment, MeshAttachment, SkinnedMeshAttachment and BoundingBox. (more coming in the future)

A RegionAttachment is just a rectangular attachment without a user-defined mesh.

If it's an unweighted mesh, you need to cast it as a MeshAttachment.
If you're using weights, it's a SkinnedMeshAttachment.

Both types of mesh attachments don't have a singular offset. Instead, each of its vertices is an offset from its parent bone. Because of this, it might not be useful for you as a source of offset data.

You can add a helper bone in the editor that you can move around where you need it and you can get the position of that bone at runtime.

ArvoAnimi

Dang, it was a meshattachment cast instead of a regionattachment. works! Thanks a lot guys

b005t3r

With MeshAttachments, if you need to get the attachment's position (sort of), you can average its vertices, like so:

else if(attachment is MeshAttachment) {
    var mesh:MeshAttachment = MeshAttachment(attachment);
    helperCoords[0] = helperCoords[1] = 0;
    var vertCount:int = mesh.vertices.length;
    for(var v:int = 0; v < vertCount; v += 2) {
        helperCoords[0] += mesh.vertices[v];
        helperCoords[1] += mesh.vertices[v + 1];
    }
    helperCoords[0] /= (vertCount / 2);
    helperCoords[1] /= (vertCount / 2);
}

(I'm aware how old this post is, I just wanted to give the answer to someone who might be looking for it, just like me 🙂 )

Nate

If you'd like to do that, consider using just the mesh hull. To do that, just change the line where vertCount is declared to:

var vertCount:int = mesh.hullLength;

The first hullLength number of vertices make up the hull. The rest of the vertices are "internal" and (almost always) inside the hull. You could also calculate the centroid of the mesh hull.

Pharan

The centroid of the mesh hull would be more reliable since averaging the vertex points— even if it's just the hull— would be subject to central tendency effects.
(eg, if your vertices aren't uniformly spaced, your average will be closer to where vertices are clumped together.)