NaNs when attempting to tessellate a polygon which contains the origin as a vertex twice #25
Description
Attempting to run the polygon described by the following vertices through Polygon::tessellate() results in the following LineString being passed to earcutr, resulting in a crash when attempting to unwrap a non-existent result inside earcutr.
[
Vertex {
pos: [
-0.38252272915132224,
-0.5349545416973491,
-2.3000000000000007,
],
normal: [
[
-0.8982972487551757,
0.05085137562241219,
0.4364357804719848,
],
],
},
Vertex {
pos: [
0.0,
0.0,
0.0,
],
normal: [
[
-0.8982972487551757,
0.05085137562241219,
0.4364357804719848,
],
],
},
Vertex {
pos: [
0.0,
0.0,
0.0,
],
normal: [
[
-0.8493784211997779,
0.4199339880208443,
0.3197057135946779,
],
],
},
Vertex {
pos: [
-0.41614886367848847,
-0.7886568930485289,
-2.2197613448986218,
],
normal: [
[
-0.8493784211997779,
0.4199339880208443,
0.3197057135946779,
],
],
},
]
LineString(
[
Coord {
x: NaN,
y: NaN,
},
Coord {
x: NaN,
y: NaN,
},
Coord {
x: NaN,
y: NaN,
},
Coord {
x: NaN,
y: NaN,
},
],
)Here's the relevant section of code:
/// Triangulate this polygon into a list of triangles, each triangle is [v0, v1, v2].
pub fn tessellate(&self) -> Vec<[Vertex; 3]> {
// If polygon has fewer than 3 vertices, nothing to tessellate
if self.vertices.len() < 3 {
return Vec::new();
}
println!("{:#?}", self.vertices);
let normal_3d = self.plane.normal.normalize();
let (u, v) = build_orthonormal_basis(normal_3d);
let origin_3d = self.vertices[0].pos;
// Flatten each vertex to 2D
let mut all_vertices_2d = Vec::with_capacity(self.vertices.len());
for vert in &self.vertices {
let offset = vert.pos.coords - origin_3d.coords;
let x = offset.dot(&u);
let y = offset.dot(&v);
all_vertices_2d.push(coord!{x: x, y: y});
}
println!("{:#?}", LineString::new(all_vertices_2d.clone()));
let triangulation = GeoPolygon::new(LineString::new(all_vertices_2d), Vec::new()).earcut_triangles_raw();
let triangle_indices = triangulation.triangle_indices;
let vertices = triangulation.vertices;