30 lines
994 B
Rust
30 lines
994 B
Rust
use bevy::{prelude::*, render::render_resource::PrimitiveTopology};
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use opensimplex_noise_rs::OpenSimplexNoise;
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use rand::Rng;
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pub fn planet() -> Mesh {
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let mut rng = rand::thread_rng();
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let simplex = OpenSimplexNoise::new(Some(rng.gen()));
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let mut mesh = Mesh::new(PrimitiveTopology::TriangleList);
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let perimeter: u32 = 1000;
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mesh.insert_attribute(
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Mesh::ATTRIBUTE_POSITION,
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(0..perimeter)
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.map(|i| {
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let mut r = simplex.eval_2d(i as f64 * 0.02, 0.) as f32 * 20.0 + 100.0;
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r += simplex.eval_2d(i as f64 * 0.05, 10.) as f32 * 10.0;
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r += simplex.eval_2d(i as f64 * 0.2, 10.) as f32 * 4.0;
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let a = std::f32::consts::TAU * i as f32 / perimeter as f32;
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[r * a.cos(), r * a.sin(), 0.]
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})
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.chain([[0., 0., 0.]].into_iter())
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.collect::<Vec<_>>(),
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);
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let mut triangles = Vec::new();
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for i in 0..perimeter {
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triangles.extend_from_slice(&[i, perimeter, (i + 1) % perimeter]);
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}
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mesh.set_indices(Some(bevy::render::mesh::Indices::U32(triangles)));
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mesh
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}
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