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|
use crate::*;
// Make Edge-Vertex
pub struct Mev<'brand, 'arena, V> {
pub loop_: ptr!(Loop),
pub vertex: ptr!(Vertex),
pub data: V,
}
impl<'brand, 'arena, V> Mev<'brand, 'arena, V> {
pub fn new(loop_: ptr!(Loop), vertex: ptr!(Vertex), data: V) -> Self {
Self {
loop_,
vertex,
data,
}
}
}
#[derive(Debug, Error)]
pub enum MevError {
#[error("vertex is not part of loop")]
VertexLoopMismatch,
}
impl<'brand, 'arena, V> Operator<'brand, 'arena, V> for Mev<'brand, 'arena, V> {
type Inverse = Kev<'brand, 'arena, V>;
type Error = MevError;
type Check = ptr!(HalfEdge);
fn check(&self, dcel: &Dcel<'brand, 'arena, V>) -> Result<Self::Check, Self::Error> {
self.vertex
.find_outgoing(self.loop_, dcel)
.ok_or(MevError::VertexLoopMismatch)
}
fn apply(
self,
dcel: &mut Dcel<'brand, 'arena, V>,
) -> Result<Self::Inverse, OperatorErr<Self, Self::Error>> {
//
// o
// a / \ d
// < <
//
// < n <
// b | | c
// o
// a / \ d
// < <
let a = try_check!(self, dcel);
let d = a.prev(dcel);
let shell = self.loop_.face(dcel).shell(dcel);
let (edge, [b, c]) = Edge::create(shell, dcel);
let vertex = shell.add_new_vertex(self.data, dcel);
dcel.follow(d, c);
dcel.follow(c, b);
dcel.follow(b, a);
b.set_loop_(self.loop_, dcel);
c.set_loop_(self.loop_, dcel);
b.update_origin(*vertex, dcel);
c.update_origin(self.vertex, dcel);
Ok(Kev { edge, vertex })
}
}
pub struct Kev<'brand, 'arena, V> {
pub edge: own!(Edge),
pub vertex: own!(Vertex),
}
impl<'brand, 'arena, V> Kev<'brand, 'arena, V> {
pub fn new(edge: own!(Edge), vertex: own!(Vertex)) -> Self {
Self { edge, vertex }
}
}
#[derive(Debug, Error)]
pub enum KevError {
#[error("half edges don't go back and forth between new and old vertex")]
NotBackForth,
#[error("new vertex is not the turning point")]
EdgeVertexMismatch,
#[error("vertex has more than one outgoing edge")]
VertexNotSingleton,
}
impl<'brand, 'arena, V> Operator<'brand, 'arena, V> for Kev<'brand, 'arena, V> {
type Inverse = Mev<'brand, 'arena, V>;
type Error = KevError;
type Check = [ptr!(HalfEdge); 2];
fn check(&self, dcel: &Dcel<'brand, 'arena, V>) -> Result<Self::Check, Self::Error> {
use KevError::*;
let [mut b, mut c] = self.edge.lens(dcel).half_edges();
if b.next() == c {
[b, c] = [c, b];
}
or_err(c.next() == b, NotBackForth)?;
or_err(b.origin().eq(*self.vertex), EdgeVertexMismatch)?;
or_err(
self.vertex.iter_outgoing(dcel).count() == 1,
VertexNotSingleton,
)?;
Ok([b.item, c.item])
}
fn apply(
self,
dcel: &mut Dcel<'brand, 'arena, V>,
) -> Result<Self::Inverse, OperatorErr<Self, Self::Error>> {
let [b, c] = try_check!(self, dcel);
let a = b.next(dcel);
let d = c.prev(dcel);
dcel.follow(d, a);
let shell = a.loop_(dcel).face(dcel).shell(dcel);
shell.remove_edge(*self.edge, dcel);
shell.remove_vertex(*self.vertex, dcel);
self.edge.destroy(dcel);
let data = self.vertex.destroy(dcel);
Ok(Mev {
data,
vertex: a.origin(dcel),
loop_: a.loop_(dcel),
})
}
}
|
