780875 - animating rotate3d produces unexpected behaviour

Status: RESOLVED DUPLICATE of bug 769892

(Core :: CSS Parsing and Computation, defect)

Description

[klaasson]

Attachment: 360deg rotation problem simplified

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:14.0) Gecko/20100101 Firefox/14.0.1
Build ID: 20120713134347

Steps to reproduce:

css3 keyframe animation to get a full 360deg rotation using rotate3d resp. matrix3d. I use 5 keys in steps of 90deg (25%) in order to determine the right turning direction.


Actual results:

rotation from 0 to 90deg works, from 90deg to 180deg works, but rotating from 180deg to 270deg causes a rotation in the opposite direction about 270deg. The same behaviour using rotate3d or matrix3d.


Expected results:

all delta rotations should turn in the same direction to get a full 360deg rotation. The example in the attached file works fine in webkit. I know, that rotateY() would do the thing, but it's not useful for complex animations.

Comment 1

[Aryeh Gregor (:ayg) (no longer with Mozilla)]

Looks like a Gecko bug to me.  If we're following the spec, it's a spec bug.  :)  The jump from 180deg to 270deg takes the longer route, not the shorter route.  I don't know enough about how to interpolate 4x4 matrices using quaternions to say precisely what's going wrong, here.  Hopefully Matt knows.

Comment 2

[Trevor Cook]

Looks like a duplicate of bug 769892.