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use crate::bounding_volume::Aabb;
use crate::math::{Isometry, Point, Real, Vector};
use crate::partitioning::Qbvh;
use crate::shape::{FeatureId, Shape, Triangle, TrianglePseudoNormals, TypedSimdCompositeShape};
use std::fmt;
use crate::utils::HashablePartialEq;
#[cfg(feature = "dim3")]
use {crate::shape::Cuboid, crate::utils::SortedPair, na::Unit};
use {
crate::shape::composite_shape::SimdCompositeShape,
crate::utils::hashmap::{Entry, HashMap},
std::collections::HashSet,
};
#[cfg(feature = "dim2")]
use crate::transformation::ear_clipping::triangulate_ear_clipping;
use crate::query::details::NormalConstraints;
#[cfg(feature = "rkyv")]
use rkyv::{bytecheck, CheckBytes};
/// Indicated an inconsistency in the topology of a triangle mesh.
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum TopologyError {
/// Found a triangle with two or three identical vertices.
BadTriangle(u32),
/// At least two adjacent triangles have opposite orientations.
BadAdjacentTrianglesOrientation {
/// The first triangle, with an orientation opposite to the second triangle.
triangle1: u32,
/// The second triangle, with an orientation opposite to the first triangle.
triangle2: u32,
/// The edge shared between the two triangles.
edge: (u32, u32),
},
}
impl fmt::Display for TopologyError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Self::BadTriangle(fid) => {
f.pad(&format!("the triangle {fid} has at least two identical vertices."))
}
Self::BadAdjacentTrianglesOrientation {
triangle1,
triangle2,
edge,
} => f.pad(&format!("the triangles {triangle1} and {triangle2} sharing the edge {:?} have opposite orientations.", edge)),
}
}
}
impl std::error::Error for TopologyError {}
/// The set of pseudo-normals of a triangle mesh.
///
/// These pseudo-normals are used for the inside-outside test of a
/// point on the triangle, as described in the paper:
/// "Signed distance computation using the angle weighted pseudonormal", Baerentzen, et al.
/// DOI: 10.1109/TVCG.2005.49
#[derive(Default, Clone)]
#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
#[cfg_attr(
feature = "rkyv",
derive(rkyv::Archive, rkyv::Deserialize, rkyv::Serialize),
archive(check_bytes)
)]
#[repr(C)]
#[cfg(feature = "dim3")]
pub struct TriMeshPseudoNormals {
/// The pseudo-normals of the vertices.
pub vertices_pseudo_normal: Vec<Vector<Real>>,
/// The pseudo-normals of the edges.
pub edges_pseudo_normal: Vec<[Vector<Real>; 3]>,
}
/// The connected-components of a triangle mesh.
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
#[cfg_attr(
feature = "rkyv",
derive(rkyv::Archive, rkyv::Deserialize, rkyv::Serialize),
archive(check_bytes)
)]
#[repr(C)]
pub struct TriMeshConnectedComponents {
/// The `face_colors[i]` gives the connected-component index
/// of the i-th face.
pub face_colors: Vec<u32>,
/// The set of faces grouped by connected components.
pub grouped_faces: Vec<u32>,
/// The range of connected components. `self.grouped_faces[self.ranges[i]..self.ranges[i + 1]]`
/// contains the indices of all the faces part of the i-th connected component.
pub ranges: Vec<usize>,
}
impl TriMeshConnectedComponents {
/// The total number of connected components.
pub fn num_connected_components(&self) -> usize {
self.ranges.len() - 1
}
}
/// A vertex of a triangle-mesh’s half-edge topology.
#[derive(Clone, Copy, Debug)]
#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
#[cfg_attr(
feature = "rkyv",
derive(rkyv::Archive, rkyv::Deserialize, rkyv::Serialize, CheckBytes),
archive(as = "Self")
)]
#[repr(C)]
pub struct TopoVertex {
/// One of the half-edge with this vertex as endpoint.
pub half_edge: u32,
}
/// A face of a triangle-mesh’s half-edge topology.
#[derive(Clone, Copy, Debug)]
#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
#[cfg_attr(
feature = "rkyv",
derive(rkyv::Archive, rkyv::Deserialize, rkyv::Serialize, CheckBytes),
archive(as = "Self")
)]
#[repr(C)]
pub struct TopoFace {
/// The half-edge adjacent to this face, with a starting point equal
/// to the first point of this face.
pub half_edge: u32,
}
/// A half-edge of a triangle-mesh’s half-edge topology.
#[derive(Clone, Copy, Debug)]
#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
#[cfg_attr(
feature = "rkyv",
derive(rkyv::Archive, rkyv::Deserialize, rkyv::Serialize, CheckBytes),
archive(as = "Self")
)]
#[repr(C)]
pub struct TopoHalfEdge {
/// The next half-edge.
pub next: u32,
/// This half-edge twin on the adjacent triangle.
///
/// This is `u32::MAX` if there is no twin.
pub twin: u32,
/// The first vertex of this edge.
pub vertex: u32,
/// The face associated to this half-edge.
pub face: u32,
}
/// The half-edge topology information of a triangle mesh.
#[derive(Default, Clone)]
#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
#[cfg_attr(
feature = "rkyv",
derive(rkyv::Archive, rkyv::Deserialize, rkyv::Serialize),
archive(check_bytes)
)]
#[repr(C)]
pub struct TriMeshTopology {
/// The vertices of this half-edge representation.
pub vertices: Vec<TopoVertex>,
/// The faces of this half-edge representation.
pub faces: Vec<TopoFace>,
/// The half-edges of this half-edge representation.
pub half_edges: Vec<TopoHalfEdge>,
}
impl TriMeshTopology {
#[cfg(feature = "dim3")]
pub(crate) fn face_half_edges_ids(&self, fid: u32) -> [u32; 3] {
let first_half_edge = self.faces[fid as usize].half_edge;
let mut result = [first_half_edge; 3];
for k in 1..3 {
let half_edge = self.half_edges[result[k - 1] as usize];
result[k] = half_edge.next;
}
result
}
}
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
#[cfg_attr(
feature = "rkyv",
derive(rkyv::Archive, rkyv::Deserialize, rkyv::Serialize),
archive(as = "Self")
)]
#[repr(C)]
#[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
/// The status of the cell of an heightfield.
pub struct TriMeshFlags(u16);
bitflags::bitflags! {
impl TriMeshFlags: u16 {
/// If set, the half-edge topology of the trimesh will be computed if possible.
const HALF_EDGE_TOPOLOGY = 1;
/// If set, the half-edge topology and connected components of the trimesh will be computed if possible.
///
/// Because of the way it is currently implemented, connected components can only be computed on
/// a mesh where the half-edge topology computation succeeds. It will no longer be the case in the
/// future once we decouple the computations.
const CONNECTED_COMPONENTS = 1 << 1;
/// If set, any triangle that results in a failing half-hedge topology computation will be deleted.
const DELETE_BAD_TOPOLOGY_TRIANGLES = 1 << 2;
/// If set, the trimesh will be assumed to be oriented (with outward normals).
///
/// The pseudo-normals of its vertices and edges will be computed.
const ORIENTED = 1 << 3;
/// If set, the duplicate vertices of the trimesh will be merged.
///
/// Two vertices with the exact same coordinates will share the same entry on the
/// vertex buffer and the index buffer is adjusted accordingly.
const MERGE_DUPLICATE_VERTICES = 1 << 4;
/// If set, the triangles sharing two vertices with identical index values will be removed.
///
/// Because of the way it is currently implemented, this methods implies that duplicate
/// vertices will be merged. It will no longer be the case in the future once we decouple
/// the computations.
const DELETE_DEGENERATE_TRIANGLES = 1 << 5;
/// If set, two triangles sharing three vertices with identical index values (in any order)
/// will be removed.
///
/// Because of the way it is currently implemented, this methods implies that duplicate
/// vertices will be merged. It will no longer be the case in the future once we decouple
/// the computations.
const DELETE_DUPLICATE_TRIANGLES = 1 << 6;
/// If set, a special treatment will be applied to contact manifold calculation to eliminate
/// or fix contacts normals that could lead to incorrect bumps in physics simulation
/// (especially on flat surfaces).
///
/// This is achieved by taking into account adjacent triangle normals when computing contact
/// points for a given triangle.
const FIX_INTERNAL_EDGES = 1 << 7 | Self::ORIENTED.bits() | Self::MERGE_DUPLICATE_VERTICES.bits();
}
}
#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
#[cfg_attr(
feature = "rkyv",
derive(rkyv::Archive, rkyv::Deserialize, rkyv::Serialize),
archive(check_bytes)
)]
#[repr(C)]
#[derive(Clone)]
/// A triangle mesh.
pub struct TriMesh {
qbvh: Qbvh<u32>,
vertices: Vec<Point<Real>>,
indices: Vec<[u32; 3]>,
#[cfg(feature = "dim3")]
pub(crate) pseudo_normals: Option<TriMeshPseudoNormals>,
topology: Option<TriMeshTopology>,
connected_components: Option<TriMeshConnectedComponents>,
flags: TriMeshFlags,
}
impl fmt::Debug for TriMesh {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "GenericTriMesh")
}
}
impl TriMesh {
/// Creates a new triangle mesh from a vertex buffer and an index buffer.
pub fn new(vertices: Vec<Point<Real>>, indices: Vec<[u32; 3]>) -> Self {
Self::with_flags(vertices, indices, TriMeshFlags::empty())
}
/// Creates a new triangle mesh from a vertex buffer and an index buffer, and flags controlling optional properties.
pub fn with_flags(
vertices: Vec<Point<Real>>,
indices: Vec<[u32; 3]>,
flags: TriMeshFlags,
) -> Self {
assert!(
!indices.is_empty(),
"A triangle mesh must contain at least one triangle."
);
let mut result = Self {
qbvh: Qbvh::new(),
vertices,
indices,
#[cfg(feature = "dim3")]
pseudo_normals: None,
topology: None,
connected_components: None,
flags: TriMeshFlags::empty(),
};
let _ = result.set_flags(flags);
if result.qbvh.raw_nodes().is_empty() {
// The Qbvh hasn’t been computed by `.set_flags`.
result.rebuild_qbvh();
}
result
}
/// Sets the flags of this triangle mesh, controlling its optional associated data.
pub fn set_flags(&mut self, flags: TriMeshFlags) -> Result<(), TopologyError> {
let mut result = Ok(());
let prev_indices_len = self.indices.len();
if !flags.contains(TriMeshFlags::HALF_EDGE_TOPOLOGY) {
self.topology = None;
}
#[cfg(feature = "dim3")]
if !flags.contains(TriMeshFlags::ORIENTED) {
self.pseudo_normals = None;
}
if !flags.contains(TriMeshFlags::CONNECTED_COMPONENTS) {
self.connected_components = None;
}
let difference = flags & !self.flags;
if difference.intersects(
TriMeshFlags::MERGE_DUPLICATE_VERTICES
| TriMeshFlags::DELETE_DEGENERATE_TRIANGLES
| TriMeshFlags::DELETE_DUPLICATE_TRIANGLES,
) {
self.merge_duplicate_vertices(
flags.contains(TriMeshFlags::DELETE_DEGENERATE_TRIANGLES),
flags.contains(TriMeshFlags::DELETE_DUPLICATE_TRIANGLES),
)
}
if difference.intersects(
TriMeshFlags::HALF_EDGE_TOPOLOGY
| TriMeshFlags::CONNECTED_COMPONENTS
| TriMeshFlags::DELETE_BAD_TOPOLOGY_TRIANGLES,
) {
result = self.compute_topology(
flags.contains(TriMeshFlags::CONNECTED_COMPONENTS),
flags.contains(TriMeshFlags::DELETE_BAD_TOPOLOGY_TRIANGLES),
);
}
#[cfg(feature = "dim3")]
if difference.contains(TriMeshFlags::ORIENTED) {
self.compute_pseudo_normals();
}
if prev_indices_len != self.indices.len() {
self.rebuild_qbvh();
}
self.flags = flags;
result
}
/// Transforms in-place the vertices of this triangle mesh.
pub fn transform_vertices(&mut self, transform: &Isometry<Real>) {
self.vertices
.iter_mut()
.for_each(|pt| *pt = transform * *pt);
self.rebuild_qbvh();
// The pseudo-normals must be rotated too.
#[cfg(feature = "dim3")]
if let Some(pseudo_normals) = &mut self.pseudo_normals {
pseudo_normals
.vertices_pseudo_normal
.iter_mut()
.for_each(|n| *n = transform * *n);
pseudo_normals.edges_pseudo_normal.iter_mut().for_each(|n| {
n[0] = transform * n[0];
n[1] = transform * n[1];
n[2] = transform * n[2];
});
}
}
/// Returns a scaled version of this triangle mesh.
pub fn scaled(mut self, scale: &Vector<Real>) -> Self {
self.vertices
.iter_mut()
.for_each(|pt| pt.coords.component_mul_assign(scale));
#[cfg(feature = "dim3")]
if let Some(pn) = &mut self.pseudo_normals {
pn.vertices_pseudo_normal.iter_mut().for_each(|n| {
n.component_mul_assign(scale);
let _ = n.try_normalize_mut(0.0);
});
pn.edges_pseudo_normal.iter_mut().for_each(|n| {
n[0].component_mul_assign(scale);
n[1].component_mul_assign(scale);
n[2].component_mul_assign(scale);
let _ = n[0].try_normalize_mut(0.0);
let _ = n[1].try_normalize_mut(0.0);
let _ = n[2].try_normalize_mut(0.0);
});
}
Self {
qbvh: self.qbvh.scaled(scale),
vertices: self.vertices,
indices: self.indices,
#[cfg(feature = "dim3")]
pseudo_normals: self.pseudo_normals,
topology: self.topology,
connected_components: self.connected_components,
flags: self.flags,
}
}
/// Appends a second triangle mesh to this triangle mesh.
pub fn append(&mut self, rhs: &TriMesh) {
let base_id = self.vertices.len() as u32;
self.vertices.extend_from_slice(rhs.vertices());
self.indices.extend(
rhs.indices()
.iter()
.map(|idx| [idx[0] + base_id, idx[1] + base_id, idx[2] + base_id]),
);
let vertices = std::mem::take(&mut self.vertices);
let indices = std::mem::take(&mut self.indices);
*self = TriMesh::with_flags(vertices, indices, self.flags);
}
/// Create a `TriMesh` from a set of points assumed to describe a counter-clockwise non-convex polygon.
///
/// This operation may fail if the input polygon is invalid, e.g. it is non-simple or has zero surface area.
#[cfg(feature = "dim2")]
pub fn from_polygon(vertices: Vec<Point<Real>>) -> Option<Self> {
triangulate_ear_clipping(&vertices).map(|indices| Self::new(vertices, indices))
}
/// A flat view of the index buffer of this mesh.
pub fn flat_indices(&self) -> &[u32] {
unsafe {
let len = self.indices.len() * 3;
let data = self.indices.as_ptr() as *const u32;
std::slice::from_raw_parts(data, len)
}
}
fn rebuild_qbvh(&mut self) {
let data = self.indices.iter().enumerate().map(|(i, idx)| {
let aabb = Triangle::new(
self.vertices[idx[0] as usize],
self.vertices[idx[1] as usize],
self.vertices[idx[2] as usize],
)
.local_aabb();
(i as u32, aabb)
});
// NOTE: we apply no dilation factor because we won't
// update this tree dynamically.
self.qbvh.clear_and_rebuild(data, 0.0);
}
/// Reverse the orientation of the triangle mesh.
pub fn reverse(&mut self) {
self.indices.iter_mut().for_each(|idx| idx.swap(0, 1));
// NOTE: the Qbvh, and connected components are not changed by this operation.
// The pseudo-normals just have to be flipped.
// The topology must be recomputed.
#[cfg(feature = "dim3")]
if let Some(pseudo_normals) = &mut self.pseudo_normals {
for n in &mut pseudo_normals.vertices_pseudo_normal {
*n = -*n;
}
for n in pseudo_normals.edges_pseudo_normal.iter_mut() {
n[0] = -n[0];
n[1] = -n[1];
n[2] = -n[2];
}
}
if self.flags.contains(TriMeshFlags::HALF_EDGE_TOPOLOGY) {
// TODO: this could be done more efficiently.
let _ = self.compute_topology(false, false);
}
}
/// Merge all duplicate vertices and adjust the index buffer accordingly.
///
/// If `delete_degenerate_triangles` is set to true, any triangle with two
/// identical vertices will be removed.
///
/// This is typically used to recover a vertex buffer from which we can deduce
/// adjacency information. between triangles by observing how the vertices are
/// shared by triangles based on the index buffer.
fn merge_duplicate_vertices(
&mut self,
delete_degenerate_triangles: bool,
delete_duplicate_triangles: bool,
) {
let mut vtx_to_id = HashMap::default();
let mut new_vertices = Vec::with_capacity(self.vertices.len());
let mut new_indices = Vec::with_capacity(self.indices.len());
let mut triangle_set = HashSet::new();
fn resolve_coord_id(
coord: &Point<Real>,
vtx_to_id: &mut HashMap<HashablePartialEq<Point<Real>>, u32>,
new_vertices: &mut Vec<Point<Real>>,
) -> u32 {
let key = HashablePartialEq::new(*coord);
let id = match vtx_to_id.entry(key) {
Entry::Occupied(entry) => entry.into_mut(),
Entry::Vacant(entry) => entry.insert(new_vertices.len() as u32),
};
if *id == new_vertices.len() as u32 {
new_vertices.push(*coord);
}
*id
}
for t in self.indices.iter() {
let va = resolve_coord_id(
&self.vertices[t[0] as usize],
&mut vtx_to_id,
&mut new_vertices,
);
let vb = resolve_coord_id(
&self.vertices[t[1] as usize],
&mut vtx_to_id,
&mut new_vertices,
);
let vc = resolve_coord_id(
&self.vertices[t[2] as usize],
&mut vtx_to_id,
&mut new_vertices,
);
let is_degenerate = va == vb || va == vc || vb == vc;
if !is_degenerate || !delete_degenerate_triangles {
if delete_duplicate_triangles {
let (c, b, a) = crate::utils::sort3(&va, &vb, &vc);
if triangle_set.insert((*a, *b, *c)) {
new_indices.push([va, vb, vc])
}
} else {
new_indices.push([va, vb, vc]);
}
}
}
new_vertices.shrink_to_fit();
self.vertices = new_vertices;
self.indices = new_indices;
// Vertices and indices changed: the pseudo-normals are no longer valid.
#[cfg(feature = "dim3")]
if self.pseudo_normals.is_some() {
self.compute_pseudo_normals();
}
// Vertices and indices changed: the topology no longer valid.
#[cfg(feature = "dim3")]
if self.topology.is_some() {
let _ = self.compute_topology(self.connected_components.is_some(), false);
}
}
#[cfg(feature = "dim3")]
/// Computes the pseudo-normals used for solid point-projection.
///
/// This computes the pseudo-normals needed by the point containment test described in
/// "Signed distance computation using the angle weighted pseudonormal", Baerentzen, et al.
/// DOI: 10.1109/TVCG.2005.49
///
/// For the point-containment test to properly detect the inside of the trimesh (i.e. to return
/// `proj.is_inside = true`), the trimesh must:
/// - Be manifold (closed, no t-junctions, etc.)
/// - Be oriented with outward normals.
///
/// If the the trimesh is correctly oriented, but is manifold everywhere except at its boundaries,
/// then the computed pseudo-normals will provide correct point-containment test results except
/// for points closest to the boundary of the mesh.
///
/// It may be useful to call `self.remove_duplicate_vertices()` before this method, in order to fix the
/// index buffer if some of the vertices of this trimesh are duplicated.
fn compute_pseudo_normals(&mut self) {
let mut vertices_pseudo_normal = vec![Vector::zeros(); self.vertices().len()];
let mut edges_pseudo_normal = HashMap::default();
let mut edges_multiplicity = HashMap::default();
for idx in self.indices() {
let vtx = self.vertices();
let tri = Triangle::new(
vtx[idx[0] as usize],
vtx[idx[1] as usize],
vtx[idx[2] as usize],
);
if let Some(n) = tri.normal() {
let ang1 = (tri.b - tri.a).angle(&(tri.c - tri.a));
let ang2 = (tri.a - tri.b).angle(&(tri.c - tri.b));
let ang3 = (tri.b - tri.c).angle(&(tri.a - tri.c));
vertices_pseudo_normal[idx[0] as usize] += *n * ang1;
vertices_pseudo_normal[idx[1] as usize] += *n * ang2;
vertices_pseudo_normal[idx[2] as usize] += *n * ang3;
let edges = [
SortedPair::new(idx[0], idx[1]),
SortedPair::new(idx[0], idx[2]),
SortedPair::new(idx[1], idx[2]),
];
for edge in &edges {
let edge_n = edges_pseudo_normal
.entry(*edge)
.or_insert_with(Vector::zeros);
*edge_n += *n; // NOTE: there is no need to multiply by the incident angle since it is always equal to PI for all the edges.
let edge_mult = edges_multiplicity.entry(*edge).or_insert(0);
*edge_mult += 1;
}
}
}
let edges_pseudo_normal = self
.indices()
.iter()
.map(|idx| {
let e0 = SortedPair::new(idx[0], idx[1]);
let e1 = SortedPair::new(idx[1], idx[2]);
let e2 = SortedPair::new(idx[2], idx[0]);
let default = Vector::zeros();
[
edges_pseudo_normal.get(&e0).copied().unwrap_or(default),
edges_pseudo_normal.get(&e1).copied().unwrap_or(default),
edges_pseudo_normal.get(&e2).copied().unwrap_or(default),
]
})
.collect();
self.pseudo_normals = Some(TriMeshPseudoNormals {
vertices_pseudo_normal,
edges_pseudo_normal,
})
}
fn delete_bad_topology_triangles(&mut self) {
let mut half_edge_set = HashSet::new();
let mut deleted_any = false;
// First, create three half-edges for each face.
self.indices.retain(|idx| {
if idx[0] == idx[1] || idx[0] == idx[2] || idx[1] == idx[2] {
deleted_any = true;
return false;
}
for k in 0..3 {
let edge_key = (idx[k as usize], idx[(k as usize + 1) % 3]);
if half_edge_set.contains(&edge_key) {
deleted_any = true;
return false;
}
}
for k in 0..3 {
let edge_key = (idx[k as usize], idx[(k as usize + 1) % 3]);
let _ = half_edge_set.insert(edge_key);
}
true
});
}
/// Computes half-edge topological information for this triangle mesh, based on its index buffer only.
///
/// This computes the half-edge representation of this triangle mesh’s topology. This is useful for advanced
/// geometric operations like trimesh-trimesh intersection geometry computation.
///
/// It may be useful to call `self.merge_duplicate_vertices(true, true)` before this method, in order to fix the
/// index buffer if some of the vertices of this trimesh are duplicated.
///
/// # Return
/// Returns `true` if the computation succeeded. Returns `false` if this mesh can’t have an half-edge representation
/// because at least three faces share the same edge.
fn compute_topology(
&mut self,
compute_connected_components: bool,
delete_bad_triangles: bool,
) -> Result<(), TopologyError> {
if delete_bad_triangles {
self.delete_bad_topology_triangles();
}
let mut topology = TriMeshTopology::default();
let mut half_edge_map = HashMap::default();
topology.vertices.resize(
self.vertices.len(),
TopoVertex {
half_edge: u32::MAX,
},
);
// First, create three half-edges for each face.
for (fid, idx) in self.indices.iter().enumerate() {
let half_edge_base_id = topology.half_edges.len() as u32;
if idx[0] == idx[1] || idx[0] == idx[2] || idx[1] == idx[2] {
return Err(TopologyError::BadTriangle(fid as u32));
}
for k in 0u32..3 {
let half_edge = TopoHalfEdge {
next: half_edge_base_id + (k + 1) % 3,
// We don’t know which one it is yet.
// If the twin doesn’t exist, we use `u32::MAX` as
// it’s (invalid) index. This value can be relied on
// by other algorithms.
twin: u32::MAX,
vertex: idx[k as usize],
face: fid as u32,
};
topology.half_edges.push(half_edge);
let edge_key = (idx[k as usize], idx[(k as usize + 1) % 3]);
if let Some(existing) = half_edge_map.insert(edge_key, half_edge_base_id + k) {
// If the same edge already exists (with the same vertex order) then
// we have two triangles sharing the same but with opposite incompatible orientations.
return Err(TopologyError::BadAdjacentTrianglesOrientation {
edge: edge_key,
triangle1: topology.half_edges[existing as usize].face,
triangle2: fid as u32,
});
}
topology.vertices[idx[k as usize] as usize].half_edge = half_edge_base_id + k;
}
topology.faces.push(TopoFace {
half_edge: half_edge_base_id,
})
}
// Second, identify twins.
for (key, he1) in &half_edge_map {
if key.0 < key.1 {
// Test, to avoid checking the same pair twice.
if let Some(he2) = half_edge_map.get(&(key.1, key.0)) {
topology.half_edges[*he1 as usize].twin = *he2;
topology.half_edges[*he2 as usize].twin = *he1;
}
}
}
self.topology = Some(topology);
if compute_connected_components {
self.compute_connected_components();
}
Ok(())
}
// NOTE: we can only compute connected components if the topology
// has been computed too. So instead of making this method
// public, the `.compute_topology` method has a boolean to
// compute the connected components too.
fn compute_connected_components(&mut self) {
let topo = self.topology.as_ref().unwrap();
let mut face_colors = vec![u32::MAX; topo.faces.len()];
let mut grouped_faces = Vec::new();
let mut ranges = vec![0];
let mut stack = vec![];
for i in 0..topo.faces.len() {
if face_colors[i] == u32::MAX {
let color = ranges.len() as u32 - 1;
face_colors[i] = color;
grouped_faces.push(i as u32);
stack.push(i as u32);
while let Some(tri_id) = stack.pop() {
let eid = topo.faces[tri_id as usize].half_edge;
let edge_a = &topo.half_edges[eid as usize];
let edge_b = &topo.half_edges[edge_a.next as usize];
let edge_c = &topo.half_edges[edge_b.next as usize];
let edges = [edge_a, edge_b, edge_c];
for edge in edges {
if let Some(twin) = topo.half_edges.get(edge.twin as usize) {
if face_colors[twin.face as usize] == u32::MAX {
face_colors[twin.face as usize] = color;
grouped_faces.push(twin.face);
stack.push(twin.face);
}
}
}
}
ranges.push(grouped_faces.len());
}
}
self.connected_components = Some(TriMeshConnectedComponents {
face_colors,
grouped_faces,
ranges,
});
}
#[allow(dead_code)] // Useful for testing.
pub(crate) fn assert_half_edge_topology_is_valid(&self) {
let topo = self
.topology
.as_ref()
.expect("No topology information found.");
assert_eq!(self.vertices.len(), topo.vertices.len());
assert_eq!(self.indices.len(), topo.faces.len());
for (face_id, (face, idx)) in topo.faces.iter().zip(self.indices.iter()).enumerate() {
let he0 = topo.half_edges[face.half_edge as usize];
assert_eq!(he0.face, face_id as u32);
assert_eq!(he0.vertex, idx[0]);
let he1 = topo.half_edges[he0.next as usize];
assert_eq!(he1.face, face_id as u32);
assert_eq!(he1.vertex, idx[1]);
let he2 = topo.half_edges[he1.next as usize];
assert_eq!(he2.face, face_id as u32);
assert_eq!(he2.vertex, idx[2]);
assert_eq!(he2.next, face.half_edge);
}
for he in &topo.half_edges {
let idx = &self.indices[he.face as usize];
assert!(he.vertex == idx[0] || he.vertex == idx[1] || he.vertex == idx[2]);
}
}
/// An iterator through all the triangles of this mesh.
pub fn triangles(&self) -> impl ExactSizeIterator<Item = Triangle> + '_ {
self.indices.iter().map(move |ids| {
Triangle::new(
self.vertices[ids[0] as usize],
self.vertices[ids[1] as usize],
self.vertices[ids[2] as usize],
)
})
}
}
impl TriMesh {
/// The flags of this triangle mesh.
pub fn flags(&self) -> TriMeshFlags {
self.flags
}
/// Compute the axis-aligned bounding box of this triangle mesh.
pub fn aabb(&self, pos: &Isometry<Real>) -> Aabb {
self.qbvh.root_aabb().transform_by(pos)
}
/// Gets the local axis-aligned bounding box of this triangle mesh.
pub fn local_aabb(&self) -> &Aabb {
self.qbvh.root_aabb()
}
/// The acceleration structure used by this triangle-mesh.
pub fn qbvh(&self) -> &Qbvh<u32> {
&self.qbvh
}
/// The number of triangles forming this mesh.
pub fn num_triangles(&self) -> usize {
self.indices.len()
}
/// Does the given feature ID identify a backface of this trimesh?
pub fn is_backface(&self, feature: FeatureId) -> bool {
if let FeatureId::Face(i) = feature {
i >= self.indices.len() as u32
} else {
false
}
}
/// Get the `i`-th triangle of this mesh.
pub fn triangle(&self, i: u32) -> Triangle {
let idx = self.indices[i as usize];
Triangle::new(
self.vertices[idx[0] as usize],
self.vertices[idx[1] as usize],
self.vertices[idx[2] as usize],
)
}
/// Returns the pseudo-normals of one of this mesh’s triangles, if it was computed.
///
/// This returns `None` if the pseudo-normals of this triangle were not computed.
/// To have its pseudo-normals computed, be sure to set the [`TriMeshFlags`] so that
/// they contain the [`TriMeshFlags::FIX_INTERNAL_EDGES`] flag.
#[cfg(feature = "dim3")]
pub fn triangle_normal_constraints(&self, i: u32) -> Option<TrianglePseudoNormals> {
if self.flags.contains(TriMeshFlags::FIX_INTERNAL_EDGES) {
let triangle = self.triangle(i);
let pseudo_normals = self.pseudo_normals.as_ref()?;
let edges_pseudo_normals = pseudo_normals.edges_pseudo_normal[i as usize];
// TODO: could the pseudo-normal be pre-normalized instead of having to renormalize
// every time we need them?
Some(TrianglePseudoNormals {
face: triangle.normal()?,
edges: [
Unit::try_new(edges_pseudo_normals[0], 1.0e-6)?,
Unit::try_new(edges_pseudo_normals[1], 1.0e-6)?,
Unit::try_new(edges_pseudo_normals[2], 1.0e-6)?,
],
})
} else {
None
}
}
#[cfg(feature = "dim2")]
#[doc(hidden)]
pub fn triangle_normal_constraints(&self, _i: u32) -> Option<TrianglePseudoNormals> {
None
}
/// The vertex buffer of this mesh.
pub fn vertices(&self) -> &[Point<Real>] {
&self.vertices
}
/// The index buffer of this mesh.
pub fn indices(&self) -> &[[u32; 3]] {
&self.indices
}
/// Returns the topology information of this trimesh, if it has been computed.
pub fn topology(&self) -> Option<&TriMeshTopology> {
self.topology.as_ref()
}
/// Returns the connected-component information of this trimesh, if it has been computed.
pub fn connected_components(&self) -> Option<&TriMeshConnectedComponents> {
self.connected_components.as_ref()
}
/// The pseudo-normals of this triangle mesh, if they have been computed.
#[cfg(feature = "dim3")]
pub fn pseudo_normals(&self) -> Option<&TriMeshPseudoNormals> {
self.pseudo_normals.as_ref()
}
}
#[cfg(feature = "dim3")]
impl From<crate::shape::HeightField> for TriMesh {
fn from(heightfield: crate::shape::HeightField) -> Self {
let (vtx, idx) = heightfield.to_trimesh();
TriMesh::new(vtx, idx)
}
}
#[cfg(feature = "dim3")]
impl From<Cuboid> for TriMesh {
fn from(cuboid: Cuboid) -> Self {
let (vtx, idx) = cuboid.to_trimesh();
TriMesh::new(vtx, idx)
}
}
impl SimdCompositeShape for TriMesh {
fn map_part_at(
&self,
i: u32,
f: &mut dyn FnMut(Option<&Isometry<Real>>, &dyn Shape, Option<&dyn NormalConstraints>),
) {
let tri = self.triangle(i);
let normals = self.triangle_normal_constraints(i);
f(
None,
&tri,
normals.as_ref().map(|n| n as &dyn NormalConstraints),
)
}
fn qbvh(&self) -> &Qbvh<u32> {
&self.qbvh
}
}
impl TypedSimdCompositeShape for TriMesh {
type PartShape = Triangle;
type PartNormalConstraints = TrianglePseudoNormals;
type PartId = u32;
#[inline(always)]
fn map_typed_part_at(
&self,
i: u32,
mut f: impl FnMut(
Option<&Isometry<Real>>,
&Self::PartShape,
Option<&Self::PartNormalConstraints>,
),
) {
let tri = self.triangle(i);
let pseudo_normals = self.triangle_normal_constraints(i);
f(None, &tri, pseudo_normals.as_ref())
}
#[inline(always)]
fn map_untyped_part_at(
&self,
i: u32,
mut f: impl FnMut(Option<&Isometry<Real>>, &dyn Shape, Option<&dyn NormalConstraints>),
) {
let tri = self.triangle(i);
let pseudo_normals = self.triangle_normal_constraints(i);
f(
None,
&tri,
pseudo_normals.as_ref().map(|n| n as &dyn NormalConstraints),
)
}
fn typed_qbvh(&self) -> &Qbvh<u32> {
&self.qbvh
}
}