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Skeleton flip and vertices order

Dono

Hello,

First, I would like to thank you for your work, it's very hard to find clean and simple software like Spine, so, thanks a lot!

I'm integrating Spine in my personal game framework and I've got a problem when the skeleton is flip on x axis.

In my graphic engine I've enabled back-face culling for performance reason (mobile development), so every polygons draw in the wrong order is not visible.

My question is probably stupid but how Spine manage skeleton's flip/vertices orders? When I flip the skeleton, all vertices are in the wrong order so character became invisible.

Here is what I do in my framework:

- On initialisation create indice buffer using degenerate triangles (with triangle strip)
- Update spine simulation
- Use my buffer editor to update my character geometry (update vertex buffer with skeleton vertices)
- Draw the character in one draw call with the renderer

I can resolve my problem with two techniques but I haven't found something similar in others runtimes (I'm using C Runtime):

- Update my indices buffer to draw in "inverse" order
- Change "VERTEX_X1", "VERTEX_X2", VERTEX_X3 and VERTEX_X4 order

Thanks again and sorry for my (bad) english.

Nate

Yep, flipping affects the vertex order. I would either disable backface culling (glDisable(GL_CULL_FACE)) when drawing skeletons or change the vertex order when flipped. Needing to update indices when a skeleton flips is not great.

Dono

Thanks,

I've finally chosen to change vertex order. But I've got another question now: when I flip the character his position change on Y axis, it's look like that he is lower after the flip.

This problem is not present when I use SpineBoy character, I think there is problem with my character skeleton (probably root bone). Did you know why my character position change after a flip? If I know, I could speak about it to my friend/animator who create my characters.

Have a nice day!

Nate

0,0 in the editor should be used as a reference for positioning the character at runtime. If a character's root bone is at 0,10 and is flipped on Y, the character will be positioned at 0,-10.

Dono

It was that, thanks again!