cyber_rider/src/planet.rs
2025-01-26 16:45:43 -08:00

146 lines
4 KiB
Rust

use avian3d::prelude::*;
use bevy::{
prelude::*,
render::{
mesh::{Indices, PrimitiveTopology},
render_asset::RenderAssetUsages,
},
};
use hexasphere::shapes::IcoSphere;
use noise::{HybridMulti, NoiseFn, SuperSimplex};
use rand::{Rng, SeedableRng};
pub const PLANET_RADIUS: f32 = 4_000.0;
pub const PLANET_HUE: f32 = 31.0;
pub const PLANET_SATURATION: f32 = 1.0;
#[derive(Component)]
pub struct CyberPlanet;
fn spawn_planet(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<StandardMaterial>>,
) {
let (mesh, shape) = gen_planet(PLANET_RADIUS);
let pcollide = (
shape,
Friction {
static_coefficient: 0.8,
dynamic_coefficient: 0.5,
combine_rule: CoefficientCombine::Average,
},
Restitution::new(0.8),
);
commands
.spawn((
Mesh3d(meshes.add(mesh)),
MeshMaterial3d(materials.add(Color::WHITE)),
Transform::default(),
Visibility::Visible,
))
.insert((
RigidBody::Static,
pcollide,
CyberPlanet,
CollisionLayers::new(LayerMask::ALL, LayerMask::ALL),
CollisionMargin(0.2),
));
}
pub struct CyberPlanetPlugin;
impl Plugin for CyberPlanetPlugin {
fn build(&self, app: &mut App) {
app.add_systems(Startup, spawn_planet);
}
}
//---------------------------------------------------------------------
// utils
//---------------------------------------------------------------------
fn gen_planet(radius: f32) -> (Mesh, Collider) {
// straight-up stolen from Bevy's impl of Mesh from Icosphere, so I can do the
// displacement before normals are calculated.
let generated = IcoSphere::new(79, |point| {
let inclination = point.y.acos();
let azimuth = point.z.atan2(point.x);
let norm_inclination = inclination / std::f32::consts::PI;
let norm_azimuth = 0.5 - (azimuth / std::f32::consts::TAU);
[norm_azimuth, norm_inclination]
});
let noise = HybridMulti::<SuperSimplex>::default();
let (mut min, mut max) = (f32::MAX, f32::MIN);
let noisy_points = generated
.raw_points()
.iter()
.map(|&p| {
let disp = (noise.get(p.as_dvec3().into()) * 0.03f64) as f32;
let pt = p + (p.normalize() * disp);
pt.into()
})
.collect::<Vec<[f32; 3]>>();
let points = noisy_points
.iter()
.map(|&p| (Vec3::from_slice(&p) * radius).into())
.collect::<Vec<[f32; 3]>>();
for p in &points {
let v = Vec3::new(p[0], p[1], p[2]);
let v = v.length();
min = v.min(min);
max = v.max(max);
}
let indices = generated.get_all_indices();
let mut idxs = Vec::new();
for idx in indices.chunks_exact(3) {
idxs.push([idx[0], idx[1], idx[2]]);
}
let indices = Indices::U32(indices);
let collider = Collider::trimesh(points.iter().map(|p| Vec3::from_slice(p)).collect(), idxs);
let mut mesh = Mesh::new(
PrimitiveTopology::TriangleList,
RenderAssetUsages::default(),
);
mesh.insert_indices(indices);
mesh.insert_attribute(Mesh::ATTRIBUTE_POSITION, points);
//mesh.insert_attribute(Mesh::ATTRIBUTE_UV_0, uvs);
mesh.duplicate_vertices();
mesh.compute_flat_normals();
let tri_list = mesh
.attribute(Mesh::ATTRIBUTE_POSITION)
.unwrap()
.as_float3()
.unwrap();
let mut rng = rand::rngs::StdRng::seed_from_u64(57);
let mut colors = Vec::new();
for _triangle in tri_list.chunks_exact(3) {
let l = 0.41;
let jitter = rng.gen_range(-0.0..=360.0f32);
let h = jitter;
let color = Color::hsl(h, PLANET_SATURATION, l)
.to_linear()
.to_f32_array();
for _ in 0..3 {
colors.push(color);
}
}
mesh.insert_attribute(Mesh::ATTRIBUTE_COLOR, colors);
(mesh, collider)
}