Struct Mesh

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pub struct Mesh {
    pub vertices: Vec<Vec3>,
    pub indices: Vec<[usize; 3]>,
    pub normals: Option<Vec<Vec3>>,
    pub uvs: Option<Vec<Vec2>>,
}

Expand description

Indexed triangle mesh with optional per-vertex normals and UVs.

normals and uvs, when present, are parallel to vertices.

Fields§

§vertices: Vec<Vec3>§indices: Vec<[usize; 3]>§normals: Option<Vec<Vec3>>§uvs: Option<Vec<Vec2>>

Implementations§

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impl Mesh

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pub fn new( vertices: Vec<Vec3>, indices: Vec<[usize; 3]>, ) -> Result<Self, GeomError>

Builds a mesh, validating that every index is in range.

§Errors

Returns GeomError::InvalidArgument when a face references a vertex index >= vertices.len().

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pub fn triangle(&self, i: usize) -> Triangle

The i-th face as a Triangle.

§Panics

Panics when i >= self.indices.len().

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pub fn triangles(&self) -> impl Iterator<Item = Triangle> + '_

Iterator over all faces as triangles.

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pub fn to_triangles(&self) -> Vec<Triangle>

All faces collected as triangles.

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pub fn face_normals(&self) -> Vec<Vec3>

Unit normal of every face (zero vector for degenerate faces).

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pub fn compute_vertex_normals(&mut self)

Computes area-weighted per-vertex normals and stores them in self.normals.

Each face contributes its (unnormalized) cross product, whose magnitude is twice the face area, so large faces dominate.

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pub fn surface_area(&self) -> f64

Total surface area (sum of face areas).

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pub fn volume(&self) -> f64

Signed enclosed volume via the divergence theorem: V = Σ aᵢ · (bᵢ × cᵢ) / 6. Positive for a closed mesh with outward-facing (counterclockwise) triangles.

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pub fn centroid(&self) -> Vec3

Centroid of the enclosed volume (center of mass at uniform density), from the signed tetrahedron decomposition against the origin.

§Panics

Panics when the signed volume is zero.

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pub fn center_of_mass_surface(&self) -> Vec3

Area-weighted centroid of the surface (center of mass of a thin shell of uniform surface density).

§Panics

Panics when the total surface area is zero.

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pub fn inertia_tensor(&self, density: f64) -> Mat3

Inertia tensor about the center of mass of the enclosed solid at the given uniform density, by signed tetrahedron decomposition (equivalent to Mirtich’s polyhedral mass-property integrals).

Each face forms the tet (0, a, b, c); its second-moment (covariance) integral is det(J) · J C J^T where J = [a b c] and C is the canonical tetrahedron covariance (1/60 diagonal, 1/120 off-diagonal). Source: Mirtich, “Fast and Accurate Computation of Polyhedral Mass Properties”, JGT 1996.

§Panics

Panics when the signed volume is zero.

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pub fn principal_inertia(&self, density: f64) -> ([f64; 3], Mat3)

Principal moments of inertia (descending) and the rotation whose columns are the principal axes.

§Panics

Panics when the signed volume is zero.

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pub fn bounding_box(&self) -> Aabb

Axis-aligned bounding box of all vertices.

§Panics

Panics when the mesh has no vertices.

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pub fn bounding_sphere(&self) -> Sphere

Approximate minimal bounding sphere by Ritter’s two-pass algorithm (at most ~5% larger than optimal).

§Panics

Panics when the mesh has no vertices.

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pub fn transform(&mut self, m: &Mat4)

Applies a general 4x4 transform to vertices; normals are mapped by the normal matrix (inverse transpose) and renormalized.

§Panics

Panics (inside Mat4::normal_matrix) when the mesh has normals and the linear part of m is singular.

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pub fn translate(&mut self, offset: Vec3)

Translates every vertex by offset.

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pub fn scale(&mut self, factor: f64)

Uniformly scales every vertex about the origin.

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pub fn rotate(&mut self, q: &Quaternion)

Rotates vertices (and normals) about the origin.

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pub fn merge(&mut self, other: &Mesh)

Appends another mesh. Optional attributes are kept only when both meshes carry them.

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pub fn flip_normals(&mut self)

Reverses the winding of every face and negates stored normals.

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pub fn weld_vertices(&mut self, tol: f64) -> usize

Merges vertices closer than tol (grid hashing with neighbor search, so any pair within tol of a common representative merges). Faces left with a repeated index are removed; stored normals and UVs are dropped. Returns the number of vertices removed.

§Panics

Panics unless tol > 0 and finite.

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pub fn remove_unused_vertices(&mut self)

Removes vertices referenced by no face, compacting attributes.

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pub fn remove_degenerate_triangles(&mut self, area_tol: f64) -> usize

Removes faces with area below area_tol or with repeated indices; returns how many were removed.

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pub fn edges(&self) -> Vec<(usize, usize)>

Unique undirected edges as sorted (min, max) index pairs, lexicographically ordered.

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pub fn adjacency(&self) -> Vec<Vec<usize>>

Vertex-to-neighbor-vertices adjacency (each list sorted, deduplicated).

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pub fn face_adjacency(&self) -> Vec<[Option<usize>; 3]>

For each face, the neighboring face across each of its edges (v0,v1), (v1,v2), (v2,v0), or None on a boundary. When an edge is shared by more than two faces, an arbitrary neighbor is reported.

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pub fn build_bvh(&self) -> Bvh

Builds a BVH over the faces (indices refer to face order).

§Panics

Panics when the mesh has no faces.

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pub fn raycast(&self, r: &Ray, bvh: Option<&Bvh>) -> Option<(usize, RayHit)>

Nearest ray hit as (face index, hit). Pass a BVH built by Mesh::build_bvh to accelerate; None falls back to brute force.

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pub fn sample_surface(&self, n: usize, rng: &mut Rng) -> Vec<Vec3>

Draws n points uniformly over the surface: faces are chosen with probability proportional to area, positions by the square-root barycentric warp.

§Panics

Panics when the total surface area is zero.

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pub fn to_obj(&self) -> String

Serializes to Wavefront OBJ (1-indexed; vn/vt written when present, referenced with the same index as the position).

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pub fn from_obj(s: &str) -> Result<Self, GeomError>

Parses Wavefront OBJ. Faces with more than three corners are fan-triangulated. Normals and UVs are kept only when every face corner references the attribute with the same index as its position and the counts match; otherwise they are dropped. Negative (relative) indices are resolved against the counts seen so far.