Index out of bounds with these two triangles

[wlinna]

The code below panics after world.update(); . These triangles are part of a larger model. Luckily, I was able to pinpoint these two triangles. There seemed to be other combinations too, but I don't what they are.

extern crate nalgebra as na;
use na::Point3;

fn main() {
    let mut world = ncollide3d::pipeline::CollisionWorld::<f32, ()>::new(0.02);
    let group = ncollide3d::pipeline::CollisionGroups::default();
    let origin = na::Isometry3::identity();

    let tri1 = ncollide3d::shape::ShapeHandle::new(ncollide3d::shape::Triangle::new(
        Point3::from_slice(&[6.292823, 6.456138, 19.66036]),
        Point3::from_slice(&[6.280472, 6.421245, 19.57066]),
        Point3::from_slice(&[6.275294, 6.449808, 19.57066]),
    ));
    let tri2 = ncollide3d::shape::ShapeHandle::new(ncollide3d::shape::Triangle::new(
        Point3::from_slice(&[6.292823, 6.456138, 19.66036]),
        Point3::from_slice(&[6.299445, 6.421245, 19.66036]),
        Point3::from_slice(&[6.280472, 6.421245, 19.57066]),
    ));

    let query_type = ncollide3d::pipeline::object::GeometricQueryType::Contacts(0.0, 0.0);

    world.add(origin, tri1, group, query_type, ());
    world.add(origin, tri2, group, query_type, ());
    world.update();
}

Here's the full backtrace:

thread 'main' panicked at 'index out of bounds: the len is 2 but the index is 2', /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libcore/slice/mod.rs:2721:14
stack backtrace:
   0:     0x55555569f9cb - backtrace::backtrace::libunwind::trace::h89fcc71e59e3bc5b
                               at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.34/src/backtrace/libunwind.rs:88
   1:     0x55555569f9cb - backtrace::backtrace::trace_unsynchronized::h0bad9be1379e729a
                               at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.34/src/backtrace/mod.rs:66
   2:     0x55555569f9cb - std::sys_common::backtrace::_print::hd3382a1f33c473da
                               at src/libstd/sys_common/backtrace.rs:47
   3:     0x55555569f9cb - std::sys_common::backtrace::print::h0ec6f03cfb8e76a6
                               at src/libstd/sys_common/backtrace.rs:36
   4:     0x55555569f9cb - std::panicking::default_hook::{{closure}}::h96cbf7b454e3f557
                               at src/libstd/panicking.rs:200
   5:     0x55555569f6a6 - std::panicking::default_hook::h95a8f00337383d83
                               at src/libstd/panicking.rs:214
   6:     0x5555556a008d - std::panicking::rust_panic_with_hook::h92f98b46e22f14ed
                               at src/libstd/panicking.rs:477
   7:     0x55555569fc12 - std::panicking::continue_panic_fmt::h25abfbb4e5b7043a
                               at src/libstd/panicking.rs:384
   8:     0x55555569faf6 - rust_begin_unwind
                               at src/libstd/panicking.rs:311
   9:     0x5555556b7bfd - core::panicking::panic_fmt::h7e9f94035af782b3
                               at src/libcore/panicking.rs:85
  10:     0x5555556b7bb5 - core::panicking::panic_bounds_check::hf0c95c4cc84d34ca
                               at src/libcore/panicking.rs:61
  11:     0x5555555c41d7 - <usize as core::slice::SliceIndex<[T]>>::index_mut::hbf6c8f008e4606d3
                               at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libcore/slice/mod.rs:2721
  12:     0x555555569107 - core::slice::<impl core::ops::index::IndexMut<I> for [T]>::index_mut::h70c677233e5fdd82
                               at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libcore/slice/mod.rs:2576
  13:     0x55555559f983 - <alloc::vec::Vec<T> as core::ops::index::IndexMut<I>>::index_mut::h38150e6ef0ae3286
                               at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/liballoc/vec.rs:1803
  14:     0x555555566aaf - ncollide3d::query::algorithms::epa3::EPA<N>::closest_points::h10a8c6a5a3b3d5e7
                               at /home/me/.cargo/registry/src/github.com-1ecc6299db9ec823/ncollide3d-0.20.1/src/query/algorithms/epa3.rs:408
  15:     0x5555555639ef - ncollide3d::query::contact::contact_support_map_support_map::contact_support_map_support_map_with_params::hf054da9b12ed13b2
                               at /home/me/.cargo/registry/src/github.com-1ecc6299db9ec823/ncollide3d-0.20.1/src/query/contact/contact_support_map_support_map.rs:72
  16:     0x55555557368f - <ncollide3d::pipeline::narrow_phase::contact_generator::convex_polyhedron_convex_polyhedron_manifold_generator::ConvexPolyhedronConvexPolyhedronManifoldGenerator<N> as ncollide3d::pipeline::narrow_phase::contact_generator::contact_manifold_generator::ContactManifoldGenerator<N>>::generate_contacts::h9c532b85c41141ad
                               at /home/me/.cargo/registry/src/github.com-1ecc6299db9ec823/ncollide3d-0.20.1/src/pipeline/narrow_phase/contact_generator/convex_polyhedron_convex_polyhedron_manifold_generator.rs:95
  17:     0x5555555bcb52 - ncollide3d::pipeline::narrow_phase::narrow_phase::NarrowPhase<N,Handle>::update_contact::hf1a7db2698f9ee56
                               at /home/me/.cargo/registry/src/github.com-1ecc6299db9ec823/ncollide3d-0.20.1/src/pipeline/narrow_phase/narrow_phase.rs:73
  18:     0x5555555bdd50 - ncollide3d::pipeline::narrow_phase::narrow_phase::NarrowPhase<N,Handle>::update_interaction::h54c765df7188d224
                               at /home/me/.cargo/registry/src/github.com-1ecc6299db9ec823/ncollide3d-0.20.1/src/pipeline/narrow_phase/narrow_phase.rs:152
  19:     0x5555555be565 - ncollide3d::pipeline::narrow_phase::narrow_phase::NarrowPhase<N,Handle>::update::ha6ddc4773b728240
                               at /home/me/.cargo/registry/src/github.com-1ecc6299db9ec823/ncollide3d-0.20.1/src/pipeline/narrow_phase/narrow_phase.rs:180
  20:     0x55555564e255 - ncollide3d::pipeline::glue::update::perform_narrow_phase::h057f30cb8be09135
                               at /home/me/.cargo/registry/src/github.com-1ecc6299db9ec823/ncollide3d-0.20.1/src/pipeline/glue/update.rs:93
  21:     0x55555564e21c - ncollide3d::pipeline::glue::update::perform_all_pipeline::h3fa81fff950f1417
                               at /home/me/.cargo/registry/src/github.com-1ecc6299db9ec823/ncollide3d-0.20.1/src/pipeline/glue/update.rs:109
  22:     0x5555555a1cdb - ncollide3d::pipeline::world::CollisionWorld<N,T>::update::hc2d3713b47a99cbe
                               at /home/me/.cargo/registry/src/github.com-1ecc6299db9ec823/ncollide3d-0.20.1/src/pipeline/world.rs:105
  23:     0x5555555642af - ncollide_bug::main::hfc0790fbffefbd02
                               at src/main.rs:24
  24:     0x5555555c6600 - std::rt::lang_start::{{closure}}::h428e54d2bded33b9
                               at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libstd/rt.rs:64
  25:     0x55555569fae3 - std::rt::lang_start_internal::{{closure}}::h4e93c1949c7a1955
                               at src/libstd/rt.rs:49
  26:     0x55555569fae3 - std::panicking::try::do_call::h9440ccd4dc467eaa
                               at src/libstd/panicking.rs:296
  27:     0x5555556a1d9a - __rust_maybe_catch_panic
                               at src/libpanic_unwind/lib.rs:80
  28:     0x5555556a059d - std::panicking::try::hc046e7ee42ee744f
                               at src/libstd/panicking.rs:275
  29:     0x5555556a059d - std::panic::catch_unwind::h27dfc457c200aee0
                               at src/libstd/panic.rs:394
  30:     0x5555556a059d - std::rt::lang_start_internal::hea1b49a567afe309
                               at src/libstd/rt.rs:48
  31:     0x5555555c65d9 - std::rt::lang_start::h84cf55c96701a481
                               at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libstd/rt.rs:64

Below are the crates I use:

approx   = "0.3.2"
alga     = "0.9.1"
nalgebra = "0.18.1"
ncollide3d = "0.20.1"

rustc 1.38.0 (625451e37 2019-09-23)

Here's an OBJ file made out of these triangles.

o Triangles
v 6.292823 6.456138 19.66036
v 6.280472 6.421245 19.57066
v 6.275294 6.449808 19.57066
v 6.292823 6.456138 19.66036
v 6.299445 6.421245 19.66036
v 6.280472 6.421245 19.57066

s off
f 1 2 3
f 4 5 6

[sebcrozet]

This looks like an error due to numerical issues, since your triangles are quite small. Thank you for the repro, this will significantly help debugging.

[wlinna]

I just updated Cargo.toml to the following

approx   = "0.3.2"
nalgebra = "0.21.0"
ncollide3d = "0.23.0"

and the crash doesn't occur anymore 🎉. Whatever you did, thank you!

I suppose I can close the issue now.