flann dependency

• depends_on('flann'), merge after Flann package #3966

libnl dependency

• merge after New packages rdma-core and libnl. #4168

libpcap dependency

• libpcap likes libnl, keep that as default to true.
• will update the url away from github release in next commit

libusb dependency

• Note 1 at bottom: should raise error if on Windows? I have no idea if it works or not

  # NOTE: this package probably works on all Linux, likely OSX
  #       *as-is*.  There are far too many options for me to understand.
  #
  #       The package likely does not work on Windows.  If you need that
  #       refer to WIN_INSTALL on their GitHub page.
  

• Note 2 at bottom: libudev is too hard to install -- users should be using system package manager to make sure they get it right / spack cannot install necessary files (requires elevated permission)

  # NOTE: this package *RELIES* on libudev, which requires the systemd PR
  #       to be fixed.  So as it stands, users must ensure that they have
  #       libudev headers and library.  On Fedora, this was available via
  #       dnf install systemd systemd-devel systemd-libs
  #       the apt repos should be similarly named (apt-cache search systemd)
  

• How do I do a sourceforge url for the official "latest stable tarball"?

• will delete FIXME in next commit with url from 3

pcl package: the real goal here

• What should default boost be. Depends on if we assume OpenNI2 installed.

  # TODO: how to give boost version AND specific boost library
  # requirements? What should they be / variants can't embed optional
  # boost deps right?
  #
  # REQUIRED boost:
  #     If OpenNI2: +system+filesystem+thread+date_time+iostreams+chrono
  #     Else:       +system+filesystem+thread+date_time+iostreams
  # OPTIONAL boost:
  #     +serialization+mpi
  

• Python treatment, should it depend on opencv+python or should we use the py-pcl?

  # TODO:
  # What to do about python?  It depends on opencv+python, but they are
  # some kind of extension, and install underneath opencv?
  # https://github.com/PointCloudLibrary/pcl/blob/6f846d242b07b7b2d5a562bbc60b3b488bbf6a47/cmake/pcl_find_python.cmake
  # There is also a python-pcl package they maintain?
  # http://pointclouds.org/news/tags/python
  

• Are the defaults acceptable or should they be made explicit (even if same as current defaults)?

  # TODO: should something be done with the default options?
  # https://github.com/PointCloudLibrary/pcl/blob/master/cmake/pcl_options.cmake
  

• Assume depth camera support? Only builds if available. But won't be used if we don't default libusb

  # TODO: spack will never be suited to nor should attempt to be suited
  # to install RGBD camera drivers.  How should spack inform users to
  # be sure that they are going to get what they want?
  #
  # The drivers require elevated permissions, and most often custom
  # modules and startup scripts.  The user is advised to try and
  # install from the official SDK or their system package manager
  # where possible.
  

  • AKA if we assume yes, it doesn't hurt, but we should maybe make libusb a full-blown requirement?

    # NOTE: libusb support REQUIRED for ANY to be used.
    #
    # Currently, the available driver support that can be built:
    # https://github.com/PointCloudLibrary/pcl/blob/b9022ebd8ad5f5300662069b5f79995d0c0e18be/CMakeLists.txt#L296-L303
    #
    # The way it works is that everything is default to TRUE, the library
    # is attempted to be found, and if not ignored.
    #
    # It takes place here:
    # https://github.com/PointCloudLibrary/pcl/blob/b89b32b5e812353e93a5c35203c70b878c8ae2b7/cmake/pcl_targets.cmake#L842-L864
    

• How do I get the right version number from qt correctly?

  # TODO: how do i check this?
  if self.spec.satisfies("^[email protected]"):
      qt_ver_str = "4"
  else:
      qt_ver_str = "5"
  args.append("-DPCL_QT_VERSION:STRING={0}".format(qt_ver_str))
  

• Choose appropriate defaults for GUI libraries (off right?): opengl, qt, and vtk for pcl.

• Choose appropriate defaults for camera support.

  • See libusb note above. +usb shouldn't be hard to compile portably (clusters etc)
  • If we don't force libusb in and people are trying to use it for camera support (very likely), they will not actually get it unless usb on.
  • Basically: create some form of bolded warning, or force it as a hard dependency.

• GitHub releases are the official releases, not mirrors.