[osg-users] Show part of geometry which intersects a specific area

[Robert Osfield]

Hi Dan,

I think an addition of the __VERSION__ check to the text.vert shader
should be sufficient. I am doing a GL3 build to see if I can reproduce
the issue, once I have I'll figure out a fix in the shader.

Robert.

On 2 April 2018 at 14:58, Daniel Emminizer, Code 5773
<dan.emminizer at nrl.navy.mil> wrote:
> Hi Robert,
>
> This morning I tried the OSG 3.6.0-rc3 tag and started getting errors.  I tracked down the problem to the commit you reference in this email below:
>
> https://github.com/openscenegraph/OpenSceneGraph/commit/9d5a22a0aa88125c3d41fc05bff72ae188b1a00b
>
> Specifically the shader lines:
>
> #ifndef GL_ES
>     gl_ClipVertex = gl_ModelViewMatrix * gl_Vertex;
> #endif
>
>
> We're trying to target the graphics cards that are supporting OpenGL Core profile, but not a compatibility profile.  When I run anything with text, I get awkward quads on the screen with various colors because this shader no longer compiles on the card.  It was working with the 3.6.0-rc2.
>
> My general configuration is configuring OSG with OPENGL_PROFILE="GLCORE", then running with environment variable "OSG_GL_CONTEXT_VERSION=3.3".
>
> Unfortunately I do not have any suggestions on what to do in this case; I do not know offhand if there is a #ifdef that you can natively use to test, but I can say that GL_ES is not defined in this configuration.  But I hope this email is helpful at least for testing the RC3 tag.  If you have any ideas I'm happy to test out on my side.
>
> Thanks,
>
>  - Dan
>
>
> -----Original Message-----
> From: osg-users [mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of Robert Osfield
> Sent: Friday, March 30, 2018 11:21 AM
> To: OpenSceneGraph Users
> Subject: Re: [osg-users] Show part of geometry which intersects a specific area
>
> Hi Ali,
>
> I had some time for looking into bugs this afternoon so I have modified the osgclip example to allow one to pass in a osgText::Text as the subgraph for clipping and this confirmed that clipping isn't working for osgText::Text in the 3.4 branch.
>
>   osgclip --text MY_TEST
>
> Is sufficient to run the new test.  You'll need update to 3.4 banch,
> 3.6 branch or master to get this example.  The commit that provides the new test code is:
>
>       https://github.com/openscenegraph/OpenSceneGraph/commit/ddce3e0079e934bce13fd5350d9380a19ec15de2
>
> I have done a review of the osgText::Text implementation in the 3.4 branch and can't see any where when clipping is explicitly disabled so I'm surprised it's not functioning OK.  Unfortunately I couldn't spot any good lead to investigate, I can only guess that there is some interaction with the way the the old osgText 3.4 code renders text using a multi-pass approach where is toggles on/off the color mask and depth writes.  Without an obvious reason for failure I can't see a way of resolving the problem for the 3.4 branch.
>
> The test also failed with OSG master and the new OpenScenGraph-3.6 branch, but this was easy to fix as osgText implementation has been almost completely rewritten since 3.4, and now uses shaders.  The fix was simply the add setting of the gl_ClipVertex into the shader and then the everything works fine.  The new osgText implementation doesn't implement using lots of toggling of state or is saddled with multi-pass approach so is cleaner, as well as provides better visual quality and some new approaches such as using Signed Distance Function (you need to enable this on osgText::Font to use it.)
>
> The fix to the OpenSceneGraph-3.6 branch is:
>
>     https://github.com/openscenegraph/OpenSceneGraph/commit/9d5a22a0aa88125c3d41fc05bff72ae188b1a00b
>
> I also updated the OpenSceneGraph-Data as this contains the shaders/text.vert this is embedded in the source of the osgText library - which the above commit modifies.
>
> As the OpenSceneGrpah-3.6.0 stable release is imminent, I would suggest just moving to the 3.6 branch or the release candidate 3 branch I'll be making this afternoon, as this should resolve the problem you are seeing.
>
> Cheers,
> Robert.
> _______________________________________________
> osg-users mailing list
> osg-users at lists.openscenegraph.org
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> _______________________________________________
> osg-users mailing list
> osg-users at lists.openscenegraph.org
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org