Fix ColladaExporter submesh index bug

[Blast545]

🦟 Bug fix

Fixes #761

Summary

The fix IMO is straightforward, use the iteration index to include properly the missing submeshes to the exported SubMeshes array.

I closed the previous PR because I had to rebase in top of ign-gazebo5.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

[chapulina]

Would it be possible to add a test with submeshes to https://github.com/ignitionrobotics/ign-gazebo/blob/ign-gazebo5/test/integration/collada_world_exporter.cc ?

[codecov]

Codecov Report

Merging #763 (532fc4a) into ign-gazebo5 (9599770) will increase coverage by 0.09%.
The diff coverage is 100.00%.

@@               Coverage Diff               @@
##           ign-gazebo5     #763      +/-   ##
===============================================
+ Coverage        65.35%   65.44%   +0.09%     
===============================================
  Files              240      240              
  Lines            17651    17651              
===============================================
+ Hits             11536    11552      +16     
+ Misses            6115     6099      -16     

Impacted Files	Coverage Δ
...ems/collada_world_exporter/ColladaWorldExporter.cc	94.17% <100.00%> (+15.53%)	⬆️

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[Blast545]

@chapulina Sure! I'll add a test there for submeshes with this PR

[Blast545]

@chapulina I added a test for sub-meshes as you asked me, the model from fuel that started the issue.

Please note though that the test only checks if there's an output, and the issue addressed with this PR was silently failing as the exported result was incorrect.

[luca-della-vedova]

I can confirm that I had the same issue and went through fixing it and... Wrote the same fix locally, then when opening a PR I saw this branch 😅

Imho it's not immediately straightforward to add a test for this, what was happening before was that multiple of the same submesh at index 0 were exported so we can't just do a check on the collada file to count the number of submeshes, we would need to check that they are different, and match the ones in the input world.
The test also seems to add quite a lot of binaries

[chapulina]

The test also seems to add quite a lot of binaries

Agreed, ideally we'd use a model as simple as possible, with just enough meshes and textures to test the functionality.

[Blast545]

@chapulina @luca-della-vedova Thanks for your comments, I added a simpler test case taken from ign-common tests.

[nkoenig]

Is the mesh_with_submeshes.dae needed?

[Blast545]

@nkoenig I addressed your comment with f1596eb. Actually the extra file was the box.dae, the intented file to test was the one with submeshes 😥. Thanks!

[Blast545]

Force-pushed to rebase on top of updated ign-gazebo5, commits weren't changed.