[tor-bugs] #16005 [Tor Browser]: webgl.min_capability_mode might be too minimal

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#16005: webgl.min_capability_mode might be too minimal
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     Reporter:           |      Owner:  mikeperry
  mikeperry              |     Status:  assigned
         Type:  defect   |  Milestone:
     Priority:  normal   |    Version:
    Component:  Tor      |   Keywords:  tbb-fingerprinting, tbb-usability-
  Browser                |  website, ff38-esr, tbb-5.0a-highrisk,
   Resolution:           |  GeorgKoppen201506R, TorBrowserTeam201507R,
Actual Points:           |  MikePerry201507
       Points:           |  Parent ID:
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Changes (by gk):

 * status:  needs_review => assigned


Comment:

 Replying to [comment:17 mikeperry]:
 > Replying to [comment:15 gk]:
 > > 1) I am a bit worried about not disabling the highp precision. Are we
 sure that all GPUs support it? It seems to be optional:
 https://community.arm.com/groups/arm-mali-graphics/blog/2013/05/29
 /benchmarking-floating-point-precision-in-mobile-gpus (while this post is
 mobile specific it might apply to the desktop world as well).
 >
 > Unfortunately highp precision seems to be required for this game to
 avoid the flickering. On my mobile and desktop CPUs,
 https://www.browserleaks.com/webgl lists the "Best Float Precision" for
 both vertex and fragment shaders as [-2^27^, 2^27^] (23). I am not sure if
 this is a function of highp or not, though. The browserleaks result didn't
 seem to change for me when toggling the pref or with the patch. Does it
 for you?

 I get the same results (that is [-2^127^, 2^127^] (23)) on all of my
 machines. We might actually be good with Tor Browser on desktop at least
 but who knows. I opened #16473 to get some solid data.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/16005#comment:23>
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