Unnecessary handedness in rotation explanation about glam-rs HOT 5 CLOSED

Thanks @bitshifter !

from glam-rs.

Ah right, handedness has confused me a bit at points. I guess looking at https://www.evl.uic.edu/ralph/508S98/coordinates.html it's more about the convention than what is going on in the math.

from glam-rs.

If you felt like rewording it I'd be happy to accept a PR. Otherwise I will get to it sometime.

from glam-rs.

For what it's worth, I found the documentation helpful and hope that it's not removed. Wouldn't the angles need to be negated if the rotations were following the right-hand rule?

from glam-rs.

Wouldn't the angles need to be negated if the rotations were following the right-hand rule?

I don't think so, only for a function like from_rotation_ypr which bakes in a notion of coordinate systems (see #79). If you look at the images on https://www.evl.uic.edu/ralph/508S98/coordinates.html rotating unit +Z +90 degrees around +Y will result in unit +X. This is true for both left-handed and right-handed systems. While conceptually in the left-handed system positive rotation is clockwise and in the right-handed system positive rotation is counter-clockwise, mathematically they are the same.

I think that is what @emilk was getting at.

Code wise:

use glam::{Mat3, Vec3};
// rotate +z 90 degrees around y giving +x
let m = Mat3::from_rotation_y(90.0_f32.to_radians());
let v = m * Vec3::unit_z();
assert!(v.abs_diff_eq(Vec3::unit_x(), core::f32::EPSILON));

from glam-rs.