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use crate::partitioning::{
BVTNodeId, BestFirstVisitStatus, BestFirstVisitor, DBVTNodeId, SimultaneousVisitor,
VisitStatus, Visitor, BVT, DBVT,
};
use na::RealField;
use std::cmp::Ordering;
use std::collections::BinaryHeap;
pub trait BVH<T, BV> {
type Node: Copy;
fn root(&self) -> Option<Self::Node>;
fn num_children(&self, node: Self::Node) -> usize;
fn child(&self, i: usize, node: Self::Node) -> Self::Node;
fn content(&self, node: Self::Node) -> (&BV, Option<&T>);
fn visit(&self, visitor: &mut impl Visitor<T, BV>) {
let mut stack = Vec::new();
if let Some(root) = self.root() {
stack.push(root);
while let Some(node) = stack.pop() {
let content = self.content(node);
match visitor.visit(content.0, content.1) {
VisitStatus::Continue => {
for i in 0..self.num_children(node) {
stack.push(self.child(i, node))
}
}
VisitStatus::ExitEarly => return,
VisitStatus::Stop => {}
}
}
}
}
fn visit_bvtt(&self, other: &impl BVH<T, BV>, visitor: &mut impl SimultaneousVisitor<T, BV>) {
let mut stack = Vec::new();
if let (Some(root1), Some(root2)) = (self.root(), other.root()) {
stack.push((root1, root2));
while let Some((node1, node2)) = stack.pop() {
let content1 = self.content(node1);
let content2 = other.content(node2);
match visitor.visit(content1.0, content1.1, content2.0, content2.1) {
VisitStatus::Continue => {
let nchild1 = self.num_children(node1);
let nchild2 = other.num_children(node2);
match (nchild1, nchild2) {
(0, 0) => {}
(0, _) => {
for j in 0..nchild2 {
let n2 = other.child(j, node2);
stack.push((node1, n2))
}
}
(_, 0) => {
for i in 0..nchild1 {
let n1 = self.child(i, node1);
stack.push((n1, node2))
}
}
(_, _) => {
for i in 0..nchild1 {
let n1 = self.child(i, node1);
for j in 0..nchild2 {
let n2 = other.child(j, node2);
stack.push((n1, n2))
}
}
}
}
}
VisitStatus::ExitEarly => return,
VisitStatus::Stop => {}
}
}
}
}
fn best_first_search<N, BFS>(&self, visitor: &mut BFS) -> Option<(Self::Node, BFS::Result)>
where
N: RealField + Copy,
BFS: BestFirstVisitor<N, T, BV>,
{
let mut queue: BinaryHeap<WeightedValue<N, Self::Node>> = BinaryHeap::new();
let mut best_cost = N::max_value().unwrap();
let mut best_result = None;
if let Some(root) = self.root() {
let (root_bv, root_data) = self.content(root);
match visitor.visit(best_cost, root_bv, root_data) {
BestFirstVisitStatus::Continue { cost, result } => {
if let Some(res) = result {
best_cost = cost;
best_result = Some((root, res));
}
queue.push(WeightedValue::new(root, -cost))
}
BestFirstVisitStatus::Stop => return None,
BestFirstVisitStatus::ExitEarly(result) => return result.map(|res| (root, res)),
}
while let Some(entry) = queue.pop() {
if -entry.cost >= best_cost {
break;
}
for i in 0..self.num_children(entry.value) {
let child = self.child(i, entry.value);
let (child_bv, child_data) = self.content(child);
match visitor.visit(best_cost, child_bv, child_data) {
BestFirstVisitStatus::Continue { cost, result } => {
if cost < best_cost {
if result.is_some() {
best_cost = cost;
best_result = result.map(|res| (child, res));
}
queue.push(WeightedValue::new(child, -cost))
}
}
BestFirstVisitStatus::ExitEarly(result) => {
return result.map(|res| (child, res)).or(best_result)
}
BestFirstVisitStatus::Stop => {}
}
}
}
}
best_result
}
}
#[derive(Copy, Clone)]
pub enum BVHImpl<'a, N: 'a + RealField + Copy, T: 'a, BV: 'a> {
BVT(&'a BVT<T, BV>),
DBVT(&'a DBVT<N, T, BV>),
}
pub enum BVHNodeId {
BVTNodeId(BVTNodeId),
DBVTNodeId(DBVTNodeId),
}
impl<'a, N: RealField + Copy, T, BV> BVHImpl<'a, N, T, BV> {
#[inline]
pub fn unwrap_bvt(self) -> &'a BVT<T, BV> {
match self {
BVHImpl::BVT(bvt) => bvt,
_ => panic!("This BVTImpl is not a BVT."),
}
}
#[inline]
pub fn unwrap_dbvt(self) -> &'a DBVT<N, T, BV> {
match self {
BVHImpl::DBVT(dbvt) => dbvt,
_ => panic!("This BVTImpl is not a DBVT."),
}
}
pub fn visit(self, visitor: &mut impl Visitor<T, BV>) {
match self {
BVHImpl::BVT(bvt) => bvt.visit(visitor),
BVHImpl::DBVT(dbvt) => dbvt.visit(visitor),
}
}
pub fn visit_bvtt(
self,
other: BVHImpl<N, T, BV>,
visitor: &mut impl SimultaneousVisitor<T, BV>,
) {
match other {
BVHImpl::BVT(bvh2) => self.visit_bvtt_dispatch(bvh2, visitor),
BVHImpl::DBVT(bvh2) => self.visit_bvtt_dispatch(bvh2, visitor),
}
}
fn visit_bvtt_dispatch(
self,
bvh2: &impl BVH<T, BV>,
visitor: &mut impl SimultaneousVisitor<T, BV>,
) {
match self {
BVHImpl::BVT(bvh1) => bvh1.visit_bvtt(bvh2, visitor),
BVHImpl::DBVT(bvh1) => bvh1.visit_bvtt(bvh2, visitor),
}
}
pub fn best_first_search<BFS>(self, visitor: &mut BFS) -> Option<(BVHNodeId, BFS::Result)>
where
BFS: BestFirstVisitor<N, T, BV>,
{
match self {
BVHImpl::BVT(bvt) => bvt
.best_first_search(visitor)
.map(|res| (BVHNodeId::BVTNodeId(res.0), res.1)),
BVHImpl::DBVT(dbvt) => dbvt
.best_first_search(visitor)
.map(|res| (BVHNodeId::DBVTNodeId(res.0), res.1)),
}
}
}
struct WeightedValue<N, T> {
pub value: T,
pub cost: N,
}
impl<N, T> WeightedValue<N, T> {
#[inline]
pub fn new(value: T, cost: N) -> WeightedValue<N, T> {
WeightedValue {
value: value,
cost: cost,
}
}
}
impl<N: PartialEq, T> PartialEq for WeightedValue<N, T> {
#[inline]
fn eq(&self, other: &WeightedValue<N, T>) -> bool {
self.cost.eq(&other.cost)
}
}
impl<N: PartialEq, T> Eq for WeightedValue<N, T> {}
impl<N: PartialOrd, T> PartialOrd for WeightedValue<N, T> {
#[inline]
fn partial_cmp(&self, other: &WeightedValue<N, T>) -> Option<Ordering> {
self.cost.partial_cmp(&other.cost)
}
}
impl<N: PartialOrd, T> Ord for WeightedValue<N, T> {
#[inline]
fn cmp(&self, other: &WeightedValue<N, T>) -> Ordering {
if self.cost < other.cost {
Ordering::Less
} else if self.cost > other.cost {
Ordering::Greater
} else {
Ordering::Equal
}
}
}