Update docs/static-library.md

[BruegelN]

I'm not sure about the embree part, because I don't use embree personaly. However I think it's not relevenat anymore. Embree always compiles as static lib when LIBIGL_WITH_EMBREE is set to true: https://github.com/libigl/libigl/blob/master/cmake/libigl.cmake#L269-L295

Shoudn't the Extra section better be integrated into External Dependencies?

What about the Compressed .h/.cpp pair part? This is outdated an can be deleted, right?

Just let me know what you think such that I can update this PR accordingly.

[jdumas]

Yeah this page definitely needs an update!

Some comments:

• You may want to use Admonition-style blocks for more visible warnings.
• Maybe add a tip block that if you set the LIBIGL_USE_STATIC_LIBRARY in the CMake directly, you need to delete or update your CMakeCache.txt for it to be taken into account.
• "Installing Embree 2.0" can go away I think.
• "Extra" should definitely go into "External dependencies" (and be updated accordingly).
• I think the part about the compressed headers can go away (@alecjacobson ?)
• The part mentioning autoexplicit.sh can be updated to point to this separate repo which contains said script. (Although I wonder if anyone has used it recently? I usually do it by hand, and would also remove it from the doc).
• The "Optional" section should also be integrated into the "External Dependency" page.
• I need to double-check, but I think a better way to install libigl now is to type make install and set the CMAKE_INSTALL_PREFIX to set the destination folder where to install libigl (this would also export the igl::core target in a cmake config file).
• There are also some html code x< that got lost in the code blocks, but those should be < and > instead.

[jdumas]

Hmm so if I type make install it will indeed correctly install libigl into the right folder, but it will also install embree, even though we don't really support installing the igl::embree module at the moment. This is annoying, because there is no way to avoid Embree's CMake calling the install() on its own targets. However, it looks like add the EXCLUDE_FROM_ALL option to the line

add_subdirectory("${EMBREE_DIR}" "embree" EXCLUDE_FROM_ALL)

in libigl.cmake does the trick, and make install will only install the main libigl target!

[BruegelN]

Thank you for your detailed feedback @jdumas! I've included most of the changes proposed by you.

The "External Dependencies" page definitely needs a rework as well! But I don't want to include it into this PR to keep the scope somewhat limited and I'm not very experienced with most the external libs. But I'll add a second PR later for the page about the libigl example project

Regarding installation with make install to CMAKE_INSTALL_PREFIX: Do you want me to added ad PR to the main libigl-repo with your fix? I could test it on macOS and a Ubuntu machine beforehand. Or just leave it for now?

---

@alecjacobson I've deleted a few section which looked outdated to me:

• "Installing Embree 2.0" -> has nothing to do with static library compilation. However the section in about embree on the "External Dependencies" pages needs to be updated.
• "compressed headers" or is there a reason to keep this?
• AntTweakBar

[jdumas]

Awesome, thanks! Yes maybe you could also create a PR to add the EXCLUDE_FROM_ALL in the libigl repo, so we can update the doc accordingly.

[jdumas]

Merged! Sorry it took a while. Appreciate your effort in improving libigl :D