[Development] qt6_add_shaders and static libraries

[Ranen Ghosh]

Hi Alexandru.  Thanks for the response.

Yes, confirmed we used target names for linking (not file paths)

> Are you perhaps adding the shadert to a static library in one project,
and then trying to reuse the static library in a different project?

Yes, this is what we are trying to do.

I've found that using the OUTPUT_TARGETS parameter returns the name of the
"special target" associated with the resources, which is not the same as
<RESOURCE_NAME>.  This special target name has a static lib of its own
generated ( for this platform it's lib<special_target_name>.a ).  So I have
a chance of massaging the cmake to find and link to this file...



Ranen Ghosh

Software Developer | EFB | tel. +1519 747 1170

 NAVBLUE <https://www.navblue.aero/> | 295 Hagey Blvd., Suite 200 | Waterloo
| AMER



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On Wed, Sep 13, 2023 at 5:02 AM Alexandru Croitor <alexandru.croitor at qt.io>
wrote:

> Hi,
>
> The object file is supposed to be automatically linked into your
> application when you link to the static library target.
> That's handled by the qt6_add_resources call that qt6_add_shaders call,
> and it assumes you use target names for linking, and not file paths.
> If it doesn't, i suspect you're doing something special in your project.
> Are you perhaps adding the shadert to a static library in one project, and
> then trying to reuse the static library in a different project?
>
>
> > On 13. Sep 2023, at 00:10, Ranen Ghosh via Development <
> development at qt-project.org> wrote:
> >
> > Hi, I've found that there's a cpp file, and then an object file,
> generated with the name qrc_<RESOURCE_NAME>.  And the object file includes
> the symbol qInitResources_<RESOURCE_NAME>
> > (See https://doc.qt.io/qt-6/qt-add-resources.html for where
> <RESOURCE_NAME> comes from, as qt6_add_shaders calls qt6_add_resources)
> >
> > So the only remaining issue is that just calling qt6_add_shaders in the
> cmake and Q_INIT_RESOURCE(<RESOURCE_NAME>) in cpp results in
> >
> > Undefined symbol: qInitResources_<RESOURCE_NAME>()
> >
> > So there is still something remaining to do in the cmake that is not
> handled by the call to qt6_add_shaders.
> >
> >
> > Ranen Ghosh
> > Software Developer | EFB | tel. +1519 747 1170
> >  NAVBLUE | 295 Hagey Blvd., Suite 200 | Waterloo | AMER
> >
> > This message is intended only for the personal, confidential, and
> authorized use of the recipient(s) named above. If you are not that person,
> you are not authorized to review, use, copy, forward, distribute or
> otherwise disclose the information contained in the message
> >
> >
> > On Tue, Sep 12, 2023 at 6:39 AM Ranen Ghosh <ranen.ghosh at navblue.aero>
> wrote:
> > Hi,
> >
> > How does one use qt6_add_shaders in static libraries?  When running an
> application that uses said static library, we get this error messages like
> this
> >
> > Failed to find shader "://shader.vert.qsb"
> >
> > We're using static linking because the target platform is iOS.  On
> Windows where we use dynamic linking, we have no problem.
> >
> > We follow this practice for qrc resources which works fine
> > "When embedding resources in static libraries,... explicitly register
> your resources by calling Q_INIT_RESOURCE() with the base name of the .qrc
> file."
> >
> >
> https://doc.qt.io/qt-6/resources.html#explicit-loading-and-unloading-of-embedded-resources
> >
> > How does this relate to shaders added with qt6_add_shaders?  From the
> examples we have seen demonstrating qt6_add_resources, it does not seem to
> involve qrc.  For example,
> >
> >
> https://github.com/qt/qtshadertools/blob/26ffa67b0212255e29ec751bc25ebef65973ee99/tests/auto/buildtimeqsb/CMakeLists.txt
> >
> > qt6_add_shaders(tst_buildtimeqsb "shaders"
> >     PREFIX
> >         "/test"
> >     FILES
> >         "color.vert"
> >         "color.frag"
> > )
> >
> >
> https://github.com/qt/qtshadertools/blob/26ffa67b0212255e29ec751bc25ebef65973ee99/tests/auto/buildtimeqsb/tst_buildtimeqsb.cpp
> >
> > QShader color_vert = getShader(QLatin1String(":/test/color.vert.qsb"));
> >
> > (The URI does not have the qrc scheme)
> >
> > Thanks,
> > Ranen
> > --
> > Development mailing list
> > Development at qt-project.org
> > https://lists.qt-project.org/listinfo/development
>
>
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