This library aims to implement some useful geometry processing algorithms purely in rust. The performance of the library is the main pursuit, but I won't sacrifice readability with some complicated tricks for that reason.
As descried in Convex polyhedral meshing for robust solid modeling, We can repair any defective mesh into a watertight solid.
For a cube whose front face is eliminated and a sphere, as shown above, we want to combine them into a solid.
fn read_obj(name: &str) -> (Vec<f64>, Vec<usize>) {
let (models, _) =
tobj::load_obj(name, &tobj::LoadOptions::default()).expect("Failed to load obj file");
let model = &models[0];
let points = model
.mesh
.positions
.iter()
.map(|x| *x as f64)
.collect::<Vec<_>>();
let triangles = Vec::from_iter(model.mesh.indices.iter().map(|x| *x as usize));
(points, triangles)
}
fn test_cube_and_sphere() {
// read cube and sphere
let (cube_points, cube_tris) = read_obj("tests/data/cube.obj");
let (sphere_points, sphere_tris) = read_obj("tests/data/sphere.obj");
// merge cube and sphere into one mesh
let n_cube_points = cube_points.len() / 3;
// merge points
let points = Vec::from_iter(cube_points.into_iter().chain(sphere_points));
let tri_in_shells = Vec::from_iter(
// cube is the first shell
vec![0; cube_tris.len() / 3]
.into_iter()
// sphere is second shell
.chain(vec![1; sphere_tris.len() / 3]),
);
// merge triangles
let triangles = Vec::from_iter(
cube_tris
.into_iter()
.chain(sphere_tris.into_iter().map(|idx| idx + n_cube_points)),
);
let (new_points, new_triangles) =
make_mesh_for_triangles(&points, &triangles, &tri_in_shells);
write_obj(&new_points, &new_triangles, "123.obj");
}
}Finally, we get a watertight mesh.
You can try it online.
TODO..