[osg-users] Please test OpenSceneGraph-3.6 branch in prep for 3.6.1

[Terry Welsh]

Confirmed. Splitting the pragma line in half fixes the problem on
Intel graphics:

#pragma import_defines( BACKDROP_COLOR, SHADOW, OUTLINE)
#pragma import_defines( SIGNED_DISTANCE_FIELD, TEXTURE_DIMENSION,
GLYPH_DIMENSION)

I'm running on Win7 64-bit, Intel HD Graphics 4000, driver version
10.18.10.4885.
- Terry

On Wed, Apr 25, 2018 at 1:38 PM, Terry Welsh <mogumbo at gmail.com> wrote:
> Thank you, Dan. That is *exactly* the problem I have with the Intel
> graphics driver. This bug affects a driver from September and the new
> one I installed last night. I'll test your workaround when I get home
> tonight and report on it.
>
> (My AMD driver, on the other hand, is a complete mess. It crashes on
> Furmark and pretty much everything else.)
>
> Robert, here is a related suggestion: how about renaming text.vert and
> text.frag to something unique? Maybe osgtext_text.frag? When I first
> tried 3.6.0 all my text was very broken because I already had a
> text.vert and text.frag in my application. It took a while to figure
> out that they were being loaded by osgText::Text even though I had
> disabled them in my own code.
> - Terry
>
>>
>> Hi Terry,
>>
>> Hey I might know this one.  Thanks for that additional info about your driver.  Do you mind retesting with a change?
>>
>> See references:
>>
>> - https://devtalk.nvidia.com/default/topic/971330/opengl/bug-report-crash-in-glcompileshader-if-using-pragma/
>> - https://software.intel.com/en-us/forums/graphics-driver-bug-reporting/topic/623485
>> - https://github.com/gwaldron/osgearth/issues/1017
>> - https://github.com/gwaldron/osgearth/pull/1106
>> - https://github.com/gwaldron/osgearth/pull/1100
>>
>> There are some older intel drivers that crash on shaders that include pragmas with too many "arguments".  The spec says that pragmas should be ignored.  But testing demonstrates severe problems with several intel drivers over a few years' period where lines like:
>>
>> #pragma import_defines( BACKDROP_COLOR, SHADOW, OUTLINE, SIGNED_DISTANCE_FIELD, TEXTURE_DIMENSION, GLYPH_DIMENSION)
>>
>> ... could cause a failure.  Breaking it up into separate lines of no more than 2 arguments each works.
>>
>> We found that the magic number for drivers is 3 -- once you get over 3 parameters, it starts to break (depending on driver version).  Could you try to edit your text.frag file to change:
>>
>> #pragma import_defines( BACKDROP_COLOR, SHADOW, OUTLINE, SIGNED_DISTANCE_FIELD, TEXTURE_DIMENSION, GLYPH_DIMENSION)
>>
>> To:
>>
>> #pragma import_defines( BACKDROP_COLOR, SHADOW, OUTLINE)
>> #pragma import_defines( SIGNED_DISTANCE_FIELD, TEXTURE_DIMENSION, GLYPH_DIMENSION)
>>
>> This breaks it into 2 lines of 3 params each.  If it's the same bug that we encountered, this might fixyour problem.
>>
>> Robert, I haven't reported this because we haven't explicitly ran into this same problem with 3.6 and text shaders yet, because we haven't run on those drivers.  Newer drivers do fix the issue.
>>
>>  - Dan
>>