bevyengine
Regression: gizmos panicking given bad output from `GlobalTransform::to_scale_rotation_translation`
Bevy version
0.14
What you did
Draw a big circle
What went wrong
Bevy panicked.
Error: The vector given to `Dir3::new_unchecked` is not normalized. The length is 0.25.
stack backtrace:
0: _rust_begin_unwind
1: core::panicking::panic_fmt
2: bevy_math::direction::assert_is_normalized
3: bevy_math::direction::Dir3::new_unchecked
4: <bevy_gizmos::circles::SphereBuilder<Config,Clear> as core::ops::drop::Drop>::drop::{{closure}}
Additional information
This is a regression not present in 0.13.
Draw a big circle
Could you elaborate on this?
I modified the 3d_gizmos example so that the spheres were very large, and also tried f32::max for a radius, but did not see this panic.
Repro is the big_space demo. I was trying to repro in a test in a PR to fix, but I can't figure out how to test this with the current setup, bevy_gizmo has no tests as far as I can tell.
Ah, found the issue. The quat from GlobalTransform::to_scale_rotation_translation is not normalized, and the sphere gizmo is exploding on that.
Almost certain I hit the same exact failure on the initial release of 0.13/12
[examples/demo.rs:155:13] scale.x * 0.505 = 5.05e18
[examples/demo.rs:153:13] translation = Vec3(
8.431322e19,
4.7312953e19,
-7.1763914e19,
)
[examples/demo.rs:154:13] rotation = Quat(
0.5,
0.0,
0.0,
0.0,
)
Yup:
// Ignore rotation due to panicking in gizmos, as of bevy 0.13
let (scale, _, translation) = transform.to_scale_rotation_translation();
Looks like sphere was moved, and the normalize was removed. We really need tests.
Fixed in a patch to 0.13: https://github.com/bevyengine/bevy/pull/12375/files
Broken at some point: https://github.com/bevyengine/bevy/blob/c6a89c2187699ed9b8e9b358408c25ca347b9053/crates/bevy_gizmos/src/circles.rs#L215
Out of curiosity, why is the GlobalTransform conversion spitting out an invalid quaternion? Is it because the transform involves shearing?
It's very large and far from the origin. Converting the affine to trs is lossy.