Struct AttributeChannel

pub struct AttributeChannel {
    pub name: String,
    pub values: Vec<Scalar>,
    pub width: usize,
    pub blend: Blend,
    pub corner_indices: Option<Vec<u32>>,
}

Per-vertex or per-corner values under a caller-chosen name.

Per-vertex (the default, corner_indices: None): one tuple per position.

Per-corner (corner_indices: Some): one index into values for every triangle corner, mirroring crate::NormalAttribute::indices. This is how source formats store texture coordinates: a box corner shared by three faces carries a different UV in each (#112). Positions stay shared, so the mesh’s adjacency and closure do not depend on attribute seams.

Invariants are checked by crate::TriMesh::validate_structure rather than enforced at construction, matching how this crate treats dirty imported data: representable, then validated at a trust boundary.

Fields

name: String

Caller-chosen identifier, unique within a mesh.

values: Vec<Scalar>

Scalar tuples, width entries each: one per vertex, or the pool the corner indices point into.

width: usize

Number of scalars per vertex. 2 for a UV, 1 for an id.

blend: Blend

How values may be combined when a vertex is created.

corner_indices: Option<Vec<u32>>

Optional per-corner tuple indices, one per entry of the mesh’s indices. None means the channel is per-vertex.

A triangle whose three entries are all Self::UNMAPPED carries no value – real files texture only some faces. A triangle mixing mapped and unmapped corners is invalid: it would have a value at some corners and nothing to interpolate towards at the others.

Implementations

impl AttributeChannel

pub const UNMAPPED: u32 = 4_294_967_295u32

Corner-index marker for a triangle that carries no value.

pub fn new( name: impl Into<String>, values: Vec<Scalar>, width: usize, blend: Blend, ) -> Self

Build a per-vertex channel from flat values.

pub fn corner_indexed( name: impl Into<String>, values: Vec<Scalar>, width: usize, blend: Blend, corner_indices: Vec<u32>, ) -> Self

Build a per-corner channel: corner_indices[c] selects the tuple for triangle corner c, or is Self::UNMAPPED.

pub fn is_corner_indexed(&self) -> bool

Whether values are addressed per triangle corner.

pub fn value_count(&self) -> usize

Number of tuples in values.

Returns 0 for a zero width rather than dividing by it, so a malformed channel is inspectable instead of panicking.

pub fn vertex_count(&self) -> usize

Number of vertices a per-vertex channel covers.

The same as Self::value_count; kept for per-vertex callers, where a tuple IS a vertex.

pub fn get(&self, vertex: usize) -> Option<&[Scalar]>

The tuple at a values index, or None when out of range.

For a per-vertex channel the index is a vertex. For a per-corner one it is an entry of corner_indices; use Self::at_corner to go from a mesh corner to its value.

pub fn at_corner( &self, mesh_indices: &[u32], corner: usize, ) -> Option<&[Scalar]>

The tuple at triangle corner corner of a mesh whose index buffer is mesh_indices, whichever way the channel is addressed.

None for an unmapped corner or any out-of-range index. That makes “no value here” a result the caller has to handle, never a zero.

Trait Implementations

impl Clone for AttributeChannel

fn clone(&self) -> AttributeChannel

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AttributeChannel

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for AttributeChannel

fn eq(&self, other: &AttributeChannel) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for AttributeChannel