Clarify component order for quaternions in scene/node page about gltf-tutorials

[emackey]

For what it's worth, the glTF spec defines the XYZW order in the Transformations Section. It might be good to duplicate that in the tutorials also, but the spec can be used as reference for filing bugs on any implementations storing them in the wrong order.

[alinen]

Unless it's difficult to change the tutorial, I advocate for adding it there to make it easier for people to learn and adopt glTF. For example, the tutorial doesn't make readers look up whether matrices use column-major order or row-major order. This is helpful!

For example, perhaps say this:

The rotation is given as a quaternion. The mathematical background of quaternions is beyond the scope of this tutorial. For now, the most important information is that a quaternion is a 4-tuple (x,y,z,w) that represents a rotation about an arbitrary angle and around an arbitrary axis. For example, the quaternion [ 0.259, 0.0, 0.0, 0.966 ] describes a rotation about 30 degrees, around the x-axis. So this quaternion can be converted into a rotation matrix, as shown in Image 4d.

[emackey]

The tutorial is all here on GitHub. Would you be willing to reformulate these suggestions in the form of a pull request? I think @javagl would probably accept a PR with these types of clarifications (and @javagl we should update the contributors/acknowledgement list if this happens).

[alinen]

Yes, of course

…

On Mon, Nov 8, 2021, 9:23 AM Ed Mackey ***@***.***> wrote: The tutorial is all here on GitHub. Would you be willing to reformulate these suggestions in the form of a pull request? I think @javagl <https://github.com/javagl> would probably accept a PR with these types of clarifications (and @javagl <https://github.com/javagl> we should update the contributors/acknowledgement list if this happens). — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#61 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAB7MSIJWNER2ZKNRN2XVCDUK7MNBANCNFSM5GB6JX4A> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

[javagl]

I can also schedule an update for this. I'm a bit busy with other stuff right now, but there are some pending issues/update requests for the tutorial, maybe I can sweep some of them out e.g. during the weekend.