1174994 - Opacity animations not tweening on elements with preserve-3d

Status: RESOLVED DUPLICATE of bug 1170394

(Core :: Graphics, defect)

Description

[Josh Carpenter [:jcarpenter]]

Overview:
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Opacity animations do not tween when applied to elements with `transform-style: preserve-3d`. Observed with keyframe animations where opacity is set to 0 and 1 in `from` and `to` respectively.


Build ID:
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* Mac OSX 10.10.3
* Oculus run time 0.5.0.1
* Horizon (on Graphene from Larch Gecko branch)


Actual results:
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Opacity keyframe animation flips opacity between the `from` and `to` values, without tweening. It does take into account animation duration. If the animation duration is set to 2s, for example, the animation stays at the `from` value until 2s has elapsed, and then flips to `to` value.


Expected results:
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Opacity should animate smoothly between `from` and `to` values, over animation duration.

Comment 1

[Josh Carpenter [:jcarpenter]]

May be related to https://bugzilla.mozilla.org/show_bug.cgi?id=1170394, where Vlad says in comment 4: 

> This is a webvr-only bug -- there is currently brokenness in DefaultComputeEffectiveTransforms that causes using an intermediate surface (which is needed for filters/opacity) to not work.

Comment 2

[Benoit Girard (:BenWa)]

(In reply to Josh Carpenter [:jcarpenter] from comment #1)
> May be related to https://bugzilla.mozilla.org/show_bug.cgi?id=1170394,
> where Vlad says in comment 4: 
> 
> > This is a webvr-only bug -- there is currently brokenness in DefaultComputeEffectiveTransforms that causes using an intermediate surface (which is needed for filters/opacity) to not work.

That would make sense. You'd get active layers which would need an intermediate surface. IIRC Vlad is saying that's webvr is taking a different code path.

Can you post a (ideally reduced) test case?