Implement basic parser for triangular meshes from .MSH version 4 (GMSH)

[gwater]

I partially implemented a parser for .MSH files (version 4) based on the current GMSH manual. Its not complete; especially missing is any support for non-Triangle elements (lines, hedrons, points, etc). Also, only the text version of the format is supported.

[codecov]

Codecov Report

Merging #52 into master will increase coverage by 24.98%.
The diff coverage is 83.82%.

@@             Coverage Diff             @@
##           master      #52       +/-   ##
===========================================
+ Coverage   67.21%   92.19%   +24.98%     
===========================================
  Files           6        7        +1     
  Lines         302      282       -20     
===========================================
+ Hits          203      260       +57     
+ Misses         99       22       -77

Impacted Files	Coverage Δ
src/MeshIO.jl	100% <100%> (ø)	⬆️
src/io/msh.jl	83.33% <83.33%> (ø)
src/io/2dm.jl	92% <0%> (+12.68%)	⬆️
src/io/obj.jl	82.6% <0%> (+17.09%)	⬆️
src/io/ply.jl	100% <0%> (+26.15%)	⬆️
src/io/stl.jl	98.33% <0%> (+34.2%)	⬆️
src/io/off.jl	100% <0%> (+43.39%)	⬆️

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[gwater]

relevant to #11

[sjkelly]

@gwater Is this good to merge?

[gwater]

Yes, it doesn't implement the complete feature set of the file format but it can handle the unimplemented cases (giving warnings) and successfully loads triangular meshes (which covers my personal use case). I'm not planning to implement additional features in this PR.

[gwater]

you should take a look at the registration method though - as I understand this is typically done in FileIO, not through the__init__() mechanism

[gwater]

I added a test case to keep coverage up.

I still don't know how to properly do the file type registration – it appear two PRs need to be applied simultaneously to FileIO and MeshIO? Guidance would be appreciated

[SimonDanisch]

I removed the init and created a proper registry entry in FileIO: JuliaIO/FileIO.jl#258

[gwater]

thanks!

[gwater]

as far as i can tell, tests ran against an outdated version of FileIO.jl

[gwater]

simplified tests a little and triggered retesting

[gwater]

ok i guess this wont work until the other PR is merged and that PR is waiting for this one 😅

[gwater]

Ok, can confirm tests pass locally when both PRs are combined:

$ julia13 MeshIO/test/runtests.jl 
Test Summary: |  Pass  Total
MeshIO        | 95360  95360

[gwater]

any chance this can move ahead?

[SimonDanisch]

Thank you :)

[gwater]

thanks!