bugGnash - The GNU Flash player - Bugs: bug #25835, OGL/accum. buffer dependency...


bug #25835: OGL/accum. buffer dependency (ERROR: OpenGL: invalid operation / flicker)

Submitted by:  Sandro Santilli <strk>
Submitted on:  Thu Mar 12 09:24:11 2009  
Category: render-openglSeverity: 3 - Normal
Release: NoneStatus: Confirmed
Privacy: PublicAssigned to: Bastiaan Jacques <bjacques>
Open/Closed: Open

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Mon Mar 16 15:09:24 2009, comment #8:

The workaround would be to disable antialiasing (what we use the accumulation buffer for), which would actually be faster. But of course you'd have jagged edges.

These days fewer and fewer vendors bother to implement the accumulation buffer, so it is of limited value anyway.

Aside from making anti-aliasing optional, my plan is to create a new GTK glue based using GLUT so we can enable multisample antialiasing, which is the most popular technique these days.

Bastiaan Jacques <bjacques>
Project MemberIn charge of this item.
Mon Mar 16 14:52:58 2009, comment #7:

Indeed it is reported elsewhere [1] that the intel video chip
doesn't support accumulation buffer.

I get using a workaround would be slower, right ?

[1] http://forum.compiz-fusion.org/showthread.php?p=49070

Sandro Santilli <strk>
Project Member
Mon Mar 16 13:26:28 2009, comment #6:

The GUI creates the window, so it decides which OpenGL features are enabled. That's probably where the error comment #2 comes from.

Bastiaan Jacques <bjacques>
Project MemberIn charge of this item.
Mon Mar 16 13:03:40 2009, comment #5:

It seems accumulation buffer is available for some of my configurations:

36 GLXFBConfigs:
visual x bf lv rg d st colorbuffer ax dp st accumbuffer ms cav
id dep cl sp sz l ci b ro r g b a bf th cl r g b a ns b eat
0x54 0 tc 0 32 0 r . . 8 8 8 8 0 0 0 0 0 0 0 0 0 None
0x55 0 tc 0 32 0 r . . 8 8 8 8 0 0 0 16 16 16 16 0 0 Slow

How is a GLXFBConfig selected by our renderer ? (or, is it?)

Sandro Santilli <strk>
Project Member
Fri Mar 13 23:39:24 2009, comment #4:

Yes, the renderer assumes the accumulation buffer is available even when it isn't. So the renderer should make sure it is before it attempts to use it.

Bastiaan Jacques <bjacques>
Project MemberIn charge of this item.
Fri Mar 13 15:27:53 2009, comment #3:

Any hint on where to look at in order to fix this bastiaan ?

Sandro Santilli <strk>
Project Member
Thu Mar 12 09:31:43 2009, comment #2:

The almighty elvis.swf also results in that ERROR printed, and nothing is rendered after the initial loading bar (which flickers itself).

Sandro Santilli <strk>
Project Member
Thu Mar 12 09:30:14 2009, comment #1:

Same error with the attached movie bitmap.swf (smaller, and produced for testing purposes by Udo again).

Also, I saw this other error is printed:
ERROR: Cannot find the double-buffered visual. Trying single-buffered visual.

(file #17663)

Sandro Santilli <strk>
Project Member
Thu Mar 12 09:24:11 2009, original submission:

Testcase: magical trevor
File: 6964trev3c.swf
md5sum: ea8bbad50ccbc52dd734dfc93a7f06a7

The visible symptom is a continuos flickering during animation.
Works fine with AGG renderer.

Sandro Santilli <strk>
Project Member


(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attach File(s):

Attached Files
file #17663:  bitmap.swf added by strk (20kB - application/x-shockwave-flash)


Depends on the following items: None found

Items that depend on this one: None found


Carbon-Copy List
  • -unavailable- added by bjacques (Updated the item)
  • -unavailable- added by strk (Submitted the item)

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    Follow 3 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Thu Mar 12 09:30:14 2009strkAttached File-=>Added bitmap.swf, #17663
    Thu Mar 12 09:28:17 2009bjacquesStatusNone=>Confirmed
      SummaryMagicalTrevor: ERROR: OpenGL: invalid operation=>OGL/accum. buffer dependency (ERROR: OpenGL: invalid operation / flicker)

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