Crate subsphere

subsphere

Sphere tessellation toolkit

This crate provides a general, easy-to-use API for working with tessellated spheres, i.e. spheres whose surface is partitioned into polygonal cells. It includes implementations for a variety of such tessellations.

Features

• Implicit Representation: Instead of storing geometry data directly, the tessellations, and the elements within them, are represented implicitly. They are compact zero-allocation Copy types that can be used to generate geometry on the fly. This lets you work with massive tessellations using very little memory.

• Versatility: This crate allows you to explore a huge variety of tessellations, all sharing a common API. There’s a bunch of adjustable parameters and you’re free to mix-and-match topologies and projections to tune the tessellation to your needs.

• Spherical Geometry: In the world of subsphere, there is only one geometric space: the sphere. All objects follow the contours of the sphere, and all calculations correctly account for this.

Examples

Construct a tessellation by refining a base tessellation

let sphere = subsphere::icosphere()
    .subdivide_edge(NonZero::new(3).unwrap())
    .with_projector(subsphere::proj::Fuller)
    .truncate();

Construct a tessellation explicitly

let sphere = subsphere::HexSphere::from_kis(
    subsphere::TriSphere::new(
        subsphere::BaseTriSphere::Icosa,
        subsphere::proj::Fuller,
        NonZero::new(9).unwrap(),
        0,
    )
).unwrap();

Write a tessellation to an OBJ file

let mut obj = String::new();
for vert in sphere.vertices() {
    let pos = vert.pos();
    obj.push_str(&format!("v {} {} {}\n", pos[0], pos[1], pos[2]));
}
for face in sphere.faces() {
    let indices = face
        .vertices()
        .map(|vert| format!("{}", vert.index() + 1)) // OBJ indices are 1-based
        .collect::<Vec<_>>();
    obj.push_str(&format!("f {}\n", indices.join(" ")));
}
std::fs::write("sphere.obj", &obj).expect("failed to write to file");

Toggle neighboring faces when a face is clicked

// Setup
let mut is_active = vec![false; sphere.num_faces()];

// For each click
let click_face = sphere.face_at(click_point);
for side in click_face.sides() {
    let neighbor_index = side.twin().inside().index();
    is_active[neighbor_index] = !is_active[neighbor_index];
}

Re-exports

pub use basetri::BaseTriSphere;

pub use hex::HexSphere;

pub use tri::TriSphere;

Modules

basetri

Contains types related to BaseTriSphere.

hex

Contains types related to HexSphere.

prelude

Bundles the traits required to ergonomically work with tessellated spheres.

proj

Contains types related to projections.

tri

Contains types related to TriSphere.

util

Contains utility functions related to spheres, tessellations and projections.

Traits

Face

Represents a “face” on a Sphere of a certain type.

HalfEdge

Represents one “side” or direction of an edge on a Sphere.

Sphere

Partitions the surface of the unit sphere into a set of spherical polygons (Faces).

Vertex

Represents a vertex on a Sphere.

Functions

icosphere

Constructs a tessellation of the unit sphere by projecting an icosahedron onto it.

octasphere

Constructs a tessellation of the unit sphere by projecting an octahedron onto it.