Bevy Mesh to Geo Polygon conversion

gistfile1.txt

This is surely incorrect, and possibly terrible. Do not use!

```
use bevy::prelude::Mesh;

use geo_types::{Coordinate, LineString, Polygon};

pub fn mesh_to_clipper_polygon(mesh: &Mesh) -> Option<Polygon> {
    let vertex_count = mesh.count_vertices();
    if let Some(positions) = mesh.attribute(Mesh::ATTRIBUTE_POSITION) {
        let mut path: Vec<Coordinate> = Vec::with_capacity(vertex_count);

        if let Some(fl3s) = positions.as_float3() {
            for fl3 in fl3s {
                path.push(Coordinate {
                    x: fl3[0] as f64,
                    y: fl3[1] as f64,
                });
            }
        }

        let poly = Polygon::new(LineString(path), vec![]);

        Some(poly)
    } else {
        None
    }
}

pub fn clipper_polygon_to_mesh(polygon: &Polygon) -> Mesh {
    let coords = &polygon.exterior().0;

    let mut mesh = Mesh::new(bevy::render::mesh::PrimitiveTopology::LineStrip);
    let mut positions = Vec::with_capacity(coords.len());
    let mut normals = Vec::with_capacity(coords.len());
    for coord in coords {
        positions.push([coord.x as f32, coord.y as f32, 0.]);
        normals.push([0.0, 0.0, 1.0]);
    }
    mesh.insert_attribute(Mesh::ATTRIBUTE_POSITION, positions);
    mesh.insert_attribute(Mesh::ATTRIBUTE_NORMAL, normals);

    mesh
}
```