[CMake] Re: OpenSceneGraph and CMake

[E. Wing]

There's actually not too much going on the OSG list so don't worry
about it too much. Perhaps the surprise was the fact that QMake also
supports Xcode generation. I'm having trouble finding specifics on it
though.


As far as CMake questions go, I actually have a couple maybe you guys
can answer now.

Currently OSG has two major dependencies on two separate projects,
OpenThreads and Producer. Typically the OSG source distributions come
packaged with both other projects (but this will not be true of CVS as
they have their own repositories). Both OpenThreads and Producer are
technically stand-alone products with their own separate build
systems. However, as a convenience, it would be very nice to be able
to construct a CMake build system that can let us build all 3 in one
shot (in place) while at the same time have a CMake build system that
can build them individually for when they are downloaded separately.

The current layout of the combined source distribution looks something
like this:

OSG_OP_OT-1.1.1/
    OpenThreads/
        include/
            OpenThreads/
        src/
            pthread_src/
            win32_src/
        lib/

    Producer/
        include/
            Producer/
        src/
        lib/

    OpenSceneGraph/
        include/
            osg/
            osgUtil/
            ...
        src/
            osg/
            osgUtil/
            ...
            osgPlugins/
        examples/
            osgforest/
            osgplanets/
            ...
        lib/


The current Makefile system currently requires you to go into
OpenThreads first and type make (because Producer also depends on
OpenThreads). Then if you want to build Producer without 'installing'
OpenThreads, you must set a bunch of special long winded environmental
variables to the paths of the headers and built libs which the
Producer Makefile is set to respond to. You repeat this step with
Producer. And then finally, you go to OpenSceneGraph and do it one
more time.

(FYI, in Xcode, I use the cross-project dependencies feature so you
can just hit build in the OpenSceneGraph Xcode project, and it
automatically references/invokes the separate Xcode projects for
OpenThreads and Producer. If CMake can be used to generate this
behavior, I would be very happy.)

Anyway, I would really like to improve this current Makefile scheme if
possible so it is more a one step build without the user having to
intervene with setting environment paths or 'installing'. At the same
time, we still need to have separate/independent build systems for
each project. I would like your suggestions on how to do this.


Not to bias the overall question (as you may have a better solution),
but one thing I have been playing with is how to reference the build
libraries. One subtle problem I've come across is that I've been
building the products in the same layout as how the source is laid
out. In the case of OpenThreads, there are two different locations
depending if you build pthreads or win32 threads, so it has made
specifying this location much trickier than I would like. I'm
wondering what the smarter thing to do here is.

Thanks,
Eric