Support compiling against imath

[dgovil]

Description of Change(s)

This is an attempt to allow USD to build against the newer imath 3 libs as well as the older openexr 2 setup.
I've verified building this against imath 3.1.4 and openexr 2.4.1 and 2.5.7.
Note: I've only verified this with the alembic plugin enabled. I currently do not build with the OpenVDB or OIIO bits enabled, however they should work the same way. I

Fixes Issue(s)

-

• I have submitted a signed Contributor License Agreement (I should be under the Apple CLA)

[jilliene]

Filed as internal issue #USD-7316

[tallytalwar]

Hi @dgovil

Thanks for sending this PR in.

I am putting together some thoughts in this review (including pointers from an internal review at Pixar).

• Could you split the logic for Imath library in its own Find module (FindImath.cmake)? And then incorporating debug build support, as noted by Nick?

• OpenExr separates out imath from version 3.0 onwards. VFX Platform 2021 is when OpenEXR is bumped to version 3.1. However in the up coming 22.08 USD release we will be moving to VFX Platform 2020, which still has OpenEXR marked as version 2.4. Though your change handles the versions appropriately by providing fallback, we feel this change might be too late in the game for 22.08 release, but we might consider it post 22.08 release.

Thanks

[tallytalwar]

@meshula noted in an internal review here at Pixar that the find module is missing debug libraries (which are named with a trailing _d). Because of this it won't be possible to debug in imath or exr on mac/linux and won't be able to link on windows with a debug build.

Nick suggested that OpenEXR 3 has got an OpenEXRConfig.cmake output file that takes care of this debug builds, but it'll be some time before we're able to take advantage of that, since vfx2021 is when openexr 3.1 is introduced.

[dgovil]

Okay this should now support looking for Imath debug files if doing a debug build or if a variable is set. @meshula does this look okay to you now?

[dgovil]

That sounds reasonable. I'll try and get on those notes ASAP, though I assume since it won't make it for 22.8, that there's no immediate urgency to it. I'll try and have the changes soon

[dgovil]

Hi , I just wanted to respond here and say I'm still going to look into this, but we had a bunch of work come up recently. I'll hit this up after I'm back from SIGGRAPH and hope to see many of y'all there too.

[tallytalwar]

No worries @dgovil. We have a couple of months before the next release :D.

[dgovil]

Just picking this up again now that SIGGRAPH is done and I've finally caught up and rested

[dgovil]

@tallytalwar The requested changes should be in now. let me know if anything stands out.

[tallytalwar]

Thanks @dgovil, a modified version of this 2818017 was pushed to dev. Closing the PR in favor of that.

[jonahjnewton]

Noting here that pxr/usd/plugin/sdrOsl/CMakeLists.txt also needs a similar fix to build with Imath @tallytalwar .

(Filed as issue #2977)

#pxr/usd/plugin/sdrOsl/CMakeLists.txt

set(PXR_PREFIX pxr/usd)
set(PXR_PACKAGE sdrOsl)

if(NOT PXR_ENABLE_OSL_SUPPORT)
    return()
endif()

if (Imath_FOUND)
    set(__OSL_IMATH_LIBS "Imath::Imath")
else()
    set(__OSL_IMATH_INCLUDE ${OPENEXR_INCLUDE_DIRS})
endif()

pxr_plugin(sdrOsl
    LIBRARIES
        gf
        tf
        vt
        ar
        ndr
        sdr
        ${OSL_QUERY_LIBRARY}
        ${OIIO_LIBRARIES}
        ${__OSL_IMATH_LIBS}

    INCLUDE_DIRS
        ${__OSL_IMATH_INCLUDE}
        ${OSL_INCLUDE_DIR}
        ${OIIO_INCLUDE_DIRS}

    PUBLIC_CLASSES
        oslParser

    PRIVATE_HEADERS
        api.h

    PYTHON_CPPFILES
        moduleDeps.cpp

    PYMODULE_CPPFILES
        module.cpp
        wrapOslParser.cpp

    PYMODULE_FILES
        __init__.py

    RESOURCE_FILES
        plugInfo.json
)

pxr_test_scripts(
    testenv/testOslParser.py
)

pxr_install_test_dir(
    SRC testenv/testOslParser.testenv
    DEST testOslParser
)

pxr_register_test(testOslParser
    PYTHON
    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testOslParser"
    EXPECTED_RETURN_CODE 0
)