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gfx-rs / genmesh

A library of mesh generation utilities.
Apache License 2.0
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Adding Icosahedral Sphere #54

Closed Rhuagh closed 7 years ago

kvark commented 7 years ago

bors r+

bors[bot] commented 7 years ago

Build succeeded

kvark commented 7 years ago

Thanks! That should be in comments

On Sep 25, 2017, at 13:35, Simon Rönnberg notifications@github.com wrote:

@Rhuagh commented on this pull request.

In src/icosphere.rs:

+use std::collections::HashMap; + +use cgmath::{InnerSpace, Vector3}; + +use {Vertex, Triangle}; +use generators::{IndexedPolygon, SharedVertex}; + +/// Icosahedral sphere with radius 1, centered at (0., 0., 0.) +#[derive(Clone, Debug)] +pub struct IcoSphere {

  • i: usize,
  • vertices: Vec<[f32; 3]>,
  • faces: Vec<[usize; 3]>, +}

  • +const T: f32 = 0.85065080835204; An icosahedrons vertices can be defined as the corner points of three orthogonal golden rectangles, which means the sides of the rectangles have the golden ratio: (1 + sqrt(5)) / 2. If you take that directly though you won't get a unit sphere, so we need to normalize the points (0, ±1, ±ratio), which gives those 2 values. I precomputed those so it wouldn't be necessary runtime.

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