771539 - Support 32bit pixel depth in GLContextProviderEGL::CreateConfig

Status: RESOLVED DUPLICATE of bug 749538

(Core :: Graphics, defect)

Description

[Marshall Culpepper [:marshall_law]]

Recent emulator builds in B2G are reporting 32bit pixel depth, but the validation logic in CreateConfig only checks for 16 or 24bit pixel depths.

The fix looks to be pretty straight forward -- just add a second check for 32bit depth when the color sizes are reported RGBA/8888.

This has also been filed as a bug in B2G's github repo:
https://github.com/mozilla-b2g/B2G/issues/51

Comment 1

[Marshall Culpepper [:marshall_law]]

Attachment: 32bpp check

Comment 2

[Marshall Culpepper [:marshall_law]]

Comment on attachment 639694 [details] [diff] [review]
32bpp check

Confirmed this is working on local emulator builds in OS X w/ B2G

Comment 3

[Benoit Jacob [:bjacob] (mostly away)]

Do you know if 32bpp will give as good performance as 16bpp on these devices? That doesn't seem to be the case of all mobile devices.

Comment 4

[Marshall Culpepper [:marshall_law]]

(In reply to Benoit Jacob [:bjacob] from comment #3)
> Do you know if 32bpp will give as good performance as 16bpp on these
> devices? That doesn't seem to be the case of all mobile devices.

Not sure, but it seems the recent builds of AOSP qemu only support 16bpp/32bpp. It could be that we need to fall back to 16bpp depth in Android (we already have a 24bpp Android fallback hardcoded, but the comments there make it sound like only a temporary fix)

Comment 5

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

Comment on attachment 639694 [details] [diff] [review]
32bpp check

This is fine, but I'm scratching my head a bit here.  Why do we care about a == 8 if we request depth == 24?  I mean the attribs request alpha == 8, but why do they do that?  That seems unnecessary...

Comment 6

[Marshall Culpepper [:marshall_law]]

(In reply to Vladimir Vukicevic [:vlad] [:vladv] from comment #5)
> This is fine, but I'm scratching my head a bit here.  Why do we care about a
> == 8 if we request depth == 24?  I mean the attribs request alpha == 8, but
> why do they do that?  That seems unnecessary...

Good question -- that looks to be an artifact of another fix from mwu in Bug 734081.

It looks like the use of 24bpp is a little confused in general, using 32bpp EGL config attributes. Maybe we should file a follow up to have someone check this out?

Comment 7

[Michael Wu [:mwu]]

Originally it didn't actually matter whether 24 or 32bpp was requested but bug 767288 changed it so there is an actual distinction.

Comment 8

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

Is it worth expanding this code out to explicitly handle 24 vs 32? (i.e. not care about alpha == 8 if 24?)  Note that reporting 32 for a screen depth is kinda busted anyway, so maybe the fix should be to detect the emulator and just return 24 instead of 32 :p

Comment 9

[Marshall Culpepper [:marshall_law]]

It looks like cjones' fix from Bug 749538 is more complete, marking this one as a duplicate.