How do you split an array of an array of 3 numbers into an vec of arrays of 3 arrays of 3 numbers?

[mystic valley]

Pardon the tongue twister, but I'm trying to do what the title says in order to group an ordered vec of verticies([f32; 3]), into a vec of faces. I'm not sure how
to coerce .collect() into doing that. My current attempt at that is below.

use itertools::Itertools;
use glam::*;

pub fn main() {
    let vertices = [([0.0, 1.0, 2.0]), ([3.0, 4.0, 5.0]), ([0.0, 1.0, 2.0]), ([0.0, 1.0, 2.0]), ([0.0, 1.0, 2.0]), ([0.0, 1.0, 2.0])];
    let faces = slice.iter().collect::<Vec<[[f32; 3], 3]>>(); //<-- broken
}

[vague dew]

Are you looking for something like windows (https://doc.rust-lang.org/stable/std/slice/struct.Windows.html) ?

[frail pasture]

There's also chunks

[mystic valley]

chunks will cause run-time errors for my usecase. I want to get a compile time error if I'm trying to give a malformed input, I.E: if i feed 5 verticies and not 3, 6, etc... , faces should throw an error like "something something only accepts [[f32; 3]; 3]", when trying to collect into an iter.

[frail pasture]

const VERTICES: &[[f32; 3]] = &[
    ([0.0, 1.0, 2.0]),
    ([3.0, 4.0, 5.0]),
    ([0.0, 1.0, 2.0]),
    ([0.0, 1.0, 2.0]),
    ([0.0, 1.0, 2.0]),
    ([0.0, 1.0, 2.0]),
];
const _: () = {
    if VERTICES.len() % 3 != 0 {
        panic!("invalid number of vertices");
    }
};

[mystic valley]

that will cause runtime error, I'd like to use iter so that i get a compile time error instead.

[frail pasture]

It is a compile error. Try it.

[mystic valley]

oh i didn't know you could do that with const

[frail pasture]

I think it would be better to make a macro for this, though. Or just take an array of arrays of arrays in the first place.

[mystic valley]

actually wait, verticies are not going to be const, verticies are going to be part of a shape generator. I need the vec of array of 3 arrays of three numbers so I can generate normals for those shapes, and those shapes are variable.

[frail pasture]

how would that make a compile error then

[mystic valley]

verticies would be generated based on user input for like radius/diameter/number of sides, so they wouldnt be const

[frail pasture]

You can't make a compile error out of runtime data

[mystic valley]

The shapes themselves are created on a pre-selected list of shapes, i want to create a function which takes the verticees of arbitrary, but valid shapes, and get normals for those.

gtg, brb

[frail pasture]

Then just store them as [[[f32; 3]; 3]]