re-enabled reordering

[pca006132]

This reverts ecd9329 and make BatchUnion use BatchBoolean instead of Compose, as there are additional issues with Compose. Will finally close #114 after the triangulation problem is resolved.

Currently, the Samples.Sponge4 test fails with

Triangulation failed! Precision = 1e-05
Error in file: /home/pca006132/code/manifold/src/polygon/src/polygon.cpp (1019): 'std::all_of(triangles.begin(), triangles.end(), [&vertPos, precision](const glm::ivec3 &tri) { return CCW(vertPos[tri[0]], vertPos[tri[1]], vertPos[tri[2]], precision) >= 0; })' is false: triangulation is not entirely CCW!

[pca006132]

Ah and interestingly the Boolean.Close is causing some problem. Will look into that.

[pca006132]

It seems that it is stuck in an infinite loop in FormLoop in the 7th iteration.

[elalish]

I upgraded our debug mode, so you should be able to run ./manifold_test --gtest_filter=Sponge4 -v to get some more details; would probably be interesting to look at the difference between your branch and master. How much does it rearrange the three ops? Is it still three differences, or is it a difference of unions now?

[elalish]

Well, I was hoping #179 would solve this problem, but it seems to still exist after merging. It's definitely a related issue though - I'll keeping looking into it.

[elalish]

Okay, it looks like we've made progress with #180 and #182; we no longer have any infinite loops or bad triangulations. Now it's just that Sponge4 has 38k degenerate triangles, which is not great. Any thoughts as to why that might be?

[pca006132]

Not sure if this is an issue with the f3d viewer or something, I see some weird lines in the triangulation which might explain the degenerate triangles:

We have 433308 triangles when reordering is enabled, comparing with 396896 triangles when it is disabled. Perhaps the triangulator forgot to perform simplification in some cases?

[elalish]

Okay, I've got a repro on master now, #183. I must say, this has been a great PR for testing!

[pca006132]

Indeed. After this is merged we can try to enable usinf compose for union which also need some fixes. Also, I can start working on the fuzzing/property-based testing, which will probably expose more subtle bugs.

[elalish]

It looks like this PR isn't breaking anything, but just exposing some degenerate triangle removal difficulties already present on master. That's fine, but before we start reordering the operations, can you think of a way that we can cache intermediate results that are reused? We don't have any great examples of this in the samples right now, but it's pretty common in design. I really don't want to force users to trigger intermediate evaluation manually.

[pca006132]

I think intermediate results are already cached? Users only need to trigger intermediate evaluation manually if they want to debug or need to do some benchmarking.

Btw, should we modify the NumDegenerateTris values for Boolean.Gyroid and Samples.Sponge4 to fix the broken tests? And then open an issue to track the degenerate triangle removal issue.

[elalish]

Interesting; I was referring to this, but I guess I'm not quite sure how common that behavior is. Maybe it's not a big deal; I should really write some more samples.

Yes, let's go ahead and update the tests and merge this. 👍

[pca006132]

Oh, because we are not using compose for now, that behavior will not occur. For compose, it may be beneficial because we may be able to get more non-intersecting manifolds, but it is not beneficial when we do boolean directly.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.15%. Comparing base (747dcd9) to head (ea721db).
Report is 389 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #171      +/-   ##
==========================================
+ Coverage   96.55%   98.15%   +1.60%     
==========================================
  Files          30       30              
  Lines        2611     2602       -9     
==========================================
+ Hits         2521     2554      +33     
+ Misses         90       48      -42     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[elalish]

Coverage is looking good 👍