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#![warn(missing_docs)]
use std::cmp;
#[derive(Debug)]
pub enum PlaneCut<T> {
Sibling(T),
Cut {
front: Vec<T>,
back: Vec<T>,
},
}
pub trait Plane: Sized + Clone {
fn cut(&self, Self) -> PlaneCut<Self>;
fn is_aligned(&self, &Self) -> bool;
}
fn add_side<T: Plane>(side: &mut Option<Box<BspNode<T>>>, mut planes: Vec<T>) {
if planes.len() != 0 {
if side.is_none() {
*side = Some(Box::new(BspNode::new()));
}
let mut node = side.as_mut().unwrap();
for p in planes.drain(..) {
node.insert(p)
}
}
}
#[derive(Clone, Debug)]
pub struct BspNode<T> {
values: Vec<T>,
front: Option<Box<BspNode<T>>>,
back: Option<Box<BspNode<T>>>,
}
impl<T> BspNode<T> {
pub fn new() -> Self {
BspNode {
values: Vec::new(),
front: None,
back: None,
}
}
pub fn is_leaf(&self) -> bool {
self.front.is_none() && self.back.is_none()
}
pub fn get_depth(&self) -> usize {
if self.values.is_empty() {
return 0
}
let df = match self.front {
Some(ref node) => node.get_depth(),
None => 0,
};
let db = match self.back {
Some(ref node) => node.get_depth(),
None => 0,
};
1 + cmp::max(df, db)
}
}
impl<T: Plane> BspNode<T> {
pub fn insert(&mut self, value: T) {
if self.values.is_empty() {
self.values.push(value);
return
}
match self.values[0].cut(value) {
PlaneCut::Sibling(value) => self.values.push(value),
PlaneCut::Cut { front, back } => {
add_side(&mut self.front, front);
add_side(&mut self.back, back);
}
}
}
pub fn order(&self, base: &T, out: &mut Vec<T>) {
let (former, latter) = match self.values.first() {
None => return,
Some(ref first) if base.is_aligned(first) => (&self.front, &self.back),
Some(_) => (&self.back, &self.front),
};
if let Some(ref node) = *former {
node.order(base, out);
}
out.extend_from_slice(&self.values);
if let Some(ref node) = *latter {
node.order(base, out);
}
}
}
#[cfg(test)]
mod tests {
extern crate rand;
use super::*;
use self::rand::Rng;
#[derive(Clone, Debug, PartialEq)]
struct Plane1D(i32, bool);
impl Plane for Plane1D {
fn cut(&self, plane: Self) -> PlaneCut<Self> {
if self.0 == plane.0 {
PlaneCut::Sibling(plane)
} else if (plane.0 > self.0) == self.1 {
PlaneCut::Cut {
front: vec![plane],
back: vec![],
}
} else {
PlaneCut::Cut {
front: vec![],
back: vec![plane],
}
}
}
fn is_aligned(&self, plane: &Self) -> bool {
self.1 == plane.1
}
}
#[test]
fn test_add_side() {
let mut node_opt = None;
let p0: Vec<Plane1D> = Vec::new();
add_side(&mut node_opt, p0);
assert!(node_opt.is_none());
let p1 = Plane1D(1, true);
add_side(&mut node_opt, vec![p1.clone()]);
assert_eq!(node_opt.as_ref().unwrap().values, vec![p1.clone()]);
assert!(node_opt.as_ref().unwrap().is_leaf());
let p23 = vec![Plane1D(0, false), Plane1D(2, false)];
add_side(&mut node_opt, p23);
let node = node_opt.unwrap();
assert_eq!(node.values, vec![p1.clone()]);
assert!(node.front.is_some() && node.back.is_some());
}
#[test]
fn test_insert_depth() {
let mut node = BspNode::new();
assert_eq!(node.get_depth(), 0);
node.insert(Plane1D(0, true));
assert_eq!(node.get_depth(), 1);
node.insert(Plane1D(6, true));
assert_eq!(node.get_depth(), 2);
node.insert(Plane1D(8, true));
assert_eq!(node.get_depth(), 3);
node.insert(Plane1D(6, true));
assert_eq!(node.get_depth(), 3);
node.insert(Plane1D(-5, false));
assert_eq!(node.get_depth(), 3);
}
#[test]
fn test_order() {
let mut rng = rand::thread_rng();
let mut node = BspNode::new();
let mut out = Vec::new();
node.order(&Plane1D(0, true), &mut out);
assert!(out.is_empty());
for _ in 0 .. 100 {
let plane = Plane1D(rng.gen(), rng.gen());
node.insert(plane);
}
node.order(&Plane1D(0, true), &mut out);
let mut out2 = out.clone();
out2.sort_by_key(|p| -p.0);
assert_eq!(out, out2);
}
}