[osg-users] DefaultFont crash issue

Wed Jan 29 17:19:48 PST 2020

Hi all,

I have new information about what Fabian has done that's weird. When he's 
been saying he's doing static linking, he's not doing what most people 
would associate that phrase with (i.e. building OSG to a library file such 
that all code is contained within and consuming that when linking OpenMW). 
Instead, it's more like what CMake calls an object library - he's building 
dependencies to intermediate-representation object files, but only doing 
translation to native code and linking once when everything's an object 
file. I wouldn't be surprised if this puts static initialisers and 
destructors in orders they've never been in before and that's what's 
causing the problem.

Hopefully this will point the investigation in the right direction.

Cheers,

Chris

On Wednesday, 29 January 2020 22:38:08 UTC, OpenSceneGraph Users wrote:
>
> Hi Robert,
>
> In relation to the DefaultFont crash issue, I noticed that my code would 
> occasionally crash on creation of osgText::Text. 
> Most of my osgText::Text is not created on the main thread. 
> In order to avoid the DefaultFont crash, I created a 
> osg::ref_ptr<osgText::Font> necessaryFont = 
> osgText::Font::getDefaultFont();
> which sticks around from the beginning of the program to the end and 
> doesn't get used by anything.
> After I did this, my code no longer crashed on osgText::Text creation.
> The OpenSceneGraph version used is 3.6.4 and on both Windows (7 64-bit) 
> and Linux (Ubuntu 16.04).
> Also when I was previously using OpenSceneGraph version 3.6.2, 
> osgText::Text creation never crashed.
>
> Regards,
> Anna
>
>
>
> On Wed, Jan 29, 2020 at 5:15 PM OpenSceneGraph Users <
> osg-... at lists.openscenegraph.org <javascript:>> wrote:
>
>> Hi Robert,
>>
>> I'm reasonably sure that Fabian's crash isn't the same issue as that 
>> example exposes.
>>
>>
>>>>    - Fabian has done something weird with either OSG or OpenMW that 
>>>>    hasn't been specified yet.
>>>>
>>>> If the codebase is the same perhaps it comes down to a sensitivity to 
>>> compiler version or dependencies?
>>>
>>
>> We have official builds for a variety of Linux distros, Windows and MacOS 
>> (and semi-official builds for Android that are generally less reliable) so 
>> we should have pretty good coverage with known-good dependency and tooling 
>> versions. As I've mentioned before, the most likely culprit for this 
>> suddenly appearing for Fabian is that we pretty much never link to OSG 
>> statically. It's a nightmare on Windows (I don't think anyone's even 
>> attempted it in the last five years) but is more feasible on Linux, where 
>> the majority of our contributors are, so I've put out a call for other 
>> testers to try and reproduce the problem.
>>
>>
>>
>> Also, Robert, I'm assuming you don't have a copy of Morrowind to test 
>> OpenMW with. Right now, Steam, GreenManGaming and Fanatical are all 
>> offering it for less than £4, but at least one of those sales ends in less 
>> than twenty hours. If you're not keen, £4 is a reasonable investment for me 
>> to make to increase cooperation between our projects, but it would help if 
>> you got back to me quickly.
>>
>> Thanks,
>>
>> Chris
>>
>> On Wednesday, 29 January 2020 14:46:02 UTC, OpenSceneGraph Users wrote:
>>>
>>> Hi Chris,
>>>
>>> Thanks the links.  I've tracked down the example you created and re-run 
>>> it on my system and on the scene graph creation of the second window/view I 
>>> get text without textures.  
>>>
>>> In summary:
>>>>
>>>>    - Fabian has done something weird with either OSG or OpenMW that 
>>>>    hasn't been specified yet.
>>>>
>>>> If the codebase is the same perhaps it comes down to a sensitivity to 
>>> compiler version or dependencies?
>>>
>>>>
>>>>    - It's beginning to feel like you're misspelling OpenMW 
>>>>    deliberately.
>>>>
>>>> Sigh.  I likely have dyslexia, while I've never been formally diagnosed 
>>> I have the traits, the downside is that I regularily get letters wrong, 
>>> don't spot mispellings.  This isn't personal, it's just an issue I have to 
>>> deal with, and unfortunately as I read/wrote code and read/write email the 
>>> community also have to accept that I don't get everything right every 
>>> time.  In other ways my brain functions pretty well so overall I can still 
>>> be productive.
>>>
>>>
>>>>    - Regarding the as-yet unresolved default font/object cache not 
>>>>    being released issue I reported in March, the ball was left in your court 
>>>>    with nothing more I could do. Hopefully enough has been linked above that 
>>>>    we can move forward with that again if you've got more time now.
>>>>
>>>>
>>> If this is the one that the attached example recreates then I will be 
>>> looking into this today.
>>>  
>>>
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