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Add utility function to generate dodecahedron

This commit is contained in:
Matthew Gordon 2020-06-20 09:13:20 -04:00
parent e1c91919b8
commit 4464a9fae6
2 changed files with 133 additions and 0 deletions
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1
src/util/mod.rs
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@ -7,3 +7,4 @@ pub mod morton;
pub mod normalizer;
mod tile_iterator;
pub use tile_iterator::{Tile, TileIterator};
pub mod polyhedra;

132
src/util/polyhedra.rs Normal file
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@ -0,0 +1,132 @@
use itertools::izip;
use nalgebra::{convert, Point3, Vector3};
use crate::materials::Material;
use crate::raycasting::Triangle;
use crate::Real;
use std::sync::Arc;
pub fn triangulate_polygon<T: Real>(
vertices: &Vec<Point3<T>>,
normal: &Vector3<T>,
material: Arc<dyn Material<T>>,
) -> Vec<Triangle<T>> {
assert!(vertices.len() >= 3);
let hinge = vertices[0];
izip!(vertices.iter().skip(1), vertices.iter().skip(2))
.map(|(a, b)| Triangle {
vertices: [hinge, *a, *b],
normals: [*normal, *normal, *normal],
material: Arc::clone(&material),
})
.collect()
}
pub fn generate_dodecahedron<T: Real>(
centre: Point3<T>,
size: T,
material: Arc<dyn Material<T>>,
) -> Vec<Triangle<T>> {
let phi = convert((1.0 + (5.0_f64).sqrt()) / 2.0);
let phi_inv = T::one() / phi;
let one = T::one();
let zero = T::zero();
let faces = vec![
vec![
Vector3::new(phi_inv, zero, phi),
Vector3::new(-phi_inv, zero, phi),
Vector3::new(-one, -one, one),
Vector3::new(zero, -phi, phi_inv),
Vector3::new(one, -one, one),
],
vec![
Vector3::new(phi_inv, zero, phi),
Vector3::new(-phi_inv, zero, phi),
Vector3::new(-one, one, one),
Vector3::new(zero, phi, phi_inv),
Vector3::new(one, one, one),
],
vec![
Vector3::new(phi_inv, zero, phi),
Vector3::new(one, -one, one),
Vector3::new(phi, -phi_inv, zero),
Vector3::new(phi, phi_inv, zero),
Vector3::new(one, one, one),
],
vec![
Vector3::new(-phi_inv, zero, phi),
Vector3::new(-one, -one, one),
Vector3::new(-phi, -phi_inv, zero),
Vector3::new(-phi, phi_inv, zero),
Vector3::new(-one, one, one),
],
vec![
Vector3::new(-one, -one, one),
Vector3::new(-phi, -phi_inv, zero),
Vector3::new(-one, -one, -one),
Vector3::new(zero, -phi, -phi_inv),
Vector3::new(zero, -phi, phi_inv),
],
vec![
Vector3::new(zero, -phi, phi_inv),
Vector3::new(zero, -phi, -phi_inv),
Vector3::new(one, -one, -one),
Vector3::new(phi, -phi_inv, zero),
Vector3::new(one, -one, one),
],
vec![
Vector3::new(zero, phi, phi_inv),
Vector3::new(zero, phi, -phi_inv),
Vector3::new(-one, one, -one),
Vector3::new(-phi, phi_inv, zero),
Vector3::new(-one, one, one),
],
vec![
Vector3::new(one, one, one),
Vector3::new(phi, phi_inv, zero),
Vector3::new(one, one, -one),
Vector3::new(zero, phi, -phi_inv),
Vector3::new(zero, phi, phi_inv),
],
vec![
Vector3::new(one, -one, -one),
Vector3::new(zero, -phi, -phi_inv),
Vector3::new(-one, -one, -one),
Vector3::new(-phi_inv, zero, -phi),
Vector3::new(phi_inv, zero, -phi),
],
vec![
Vector3::new(one, one, -one),
Vector3::new(zero, phi, -phi_inv),
Vector3::new(-one, one, -one),
Vector3::new(-phi_inv, zero, -phi),
Vector3::new(phi_inv, zero, -phi),
],
vec![
Vector3::new(one, one, -one),
Vector3::new(phi, phi_inv, zero),
Vector3::new(phi, -phi_inv, zero),
Vector3::new(one, -one, -one),
Vector3::new(phi_inv, zero, -phi),
],
vec![
Vector3::new(-one, one, -one),
Vector3::new(-phi, phi_inv, zero),
Vector3::new(-phi, -phi_inv, zero),
Vector3::new(-one, -one, -one),
Vector3::new(-phi_inv, zero, -phi),
],
];
let scale = size * convert(3f64.sqrt() / 2.0);
faces
.iter()
.flat_map(|face| {
let normal = (face[1] - face[0]).cross(&(face[2] - face[1]));
let transformed_face = face.iter().map(|v| centre + v * scale).collect();
triangulate_polygon(&transformed_face, &normal, Arc::clone(&material))
})
.collect()
}