Noob steps

src/main.rs

@@ -1,3 +1,10 @@
+use bevy::{
+    prelude::{
+        App, Assets, Camera3dBundle, Color, Commands, DefaultPlugins, Mesh, PbrBundle, ResMut,
+        Resource, StandardMaterial, Transform, Vec3,
+    },
+    render::render_resource::PrimitiveTopology,
+};
 use nalgebra::base::{Matrix3, Vector3};
 use rand::{distributions::Uniform, prelude::Distribution, rngs::SmallRng, Rng, SeedableRng};
 use std::collections::HashSet;
@@ -52,11 +59,14 @@ impl Transformations {
     }
 }
 
+#[derive(Resource)]
 struct Walk {
     points: Vec<Point>,
     new_points: Vec<Point>,
     pivot_dist: Uniform<usize>,
     set: HashSet<Point>,
+    rng: SmallRng,
+    transformations: Transformations,
 }
 
 impl Walk {
@@ -71,22 +81,28 @@ impl Walk {
 
         let set = HashSet::with_capacity(n);
 
+        let rng = SmallRng::seed_from_u64(42);
+
+        let transformations = Transformations::new();
+
         Self {
             points,
             new_points,
             pivot_dist,
             set,
+            rng,
+            transformations,
         }
     }
 
-    pub fn pivot(&mut self, rng: &mut impl Rng, transformations: &Transformations) {
+    pub fn pivot(&mut self) {
         loop {
             self.set.clear();
             self.new_points.clear();
 
-            let m = transformations.rand(rng);
+            let m = self.transformations.rand(&mut self.rng);
 
-            let pivot_ind = self.pivot_dist.sample(rng);
+            let pivot_ind = self.pivot_dist.sample(&mut self.rng);
 
             let (s1, s2) = self.points.split_at_mut(pivot_ind + 1);
             let pivot = unsafe { s1.get_unchecked(pivot_ind) };
@@ -110,15 +126,49 @@ impl Walk {
     }
 }
 
-fn main() {
-    let transformations = Transformations::new();
-
-    let n = 1_000;
-
-    let seed = 42;
-    let mut rng = SmallRng::seed_from_u64(seed);
-
-    let mut walk = Walk::new(n);
-
-    walk.pivot(&mut rng, &transformations);
+fn setup(mut commands: Commands) {
+    commands.spawn(Camera3dBundle {
+        transform: Transform::from_xyz(80.0, 80.0, 80.0)
+            .looking_at(Vec3::new(0.0, 0.0, 0.0), Vec3::Y),
+        ..Default::default()
+    });
+}
+
+fn pivot(
+    mut commands: Commands,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<StandardMaterial>>,
+    mut walk: ResMut<Walk>,
+) {
+    let blue = materials.add(Color::BLUE.into());
+
+    let mut mesh = Mesh::new(PrimitiveTopology::LineStrip);
+    mesh.insert_attribute(
+        Mesh::ATTRIBUTE_POSITION,
+        walk.points
+            .iter()
+            .map(|p| Vec3::new(p.x as f32, p.y as f32, p.z as f32))
+            .collect::<Vec<_>>(),
+    );
+
+    commands.spawn(PbrBundle {
+        mesh: meshes.add(mesh),
+        material: blue,
+        ..Default::default()
+    });
+
+    walk.pivot();
+}
+
+fn main() {
+    let n = 250;
+
+    let walk = Walk::new(n);
+
+    App::new()
+        .add_plugins(DefaultPlugins)
+        .insert_resource(walk)
+        .add_startup_system(setup)
+        .add_system(pivot)
+        .run();
 }