use std::cmp::Reverse;
use std::collections::{BTreeSet, BinaryHeap};
use std::ops::Bound::{Excluded, Unbounded};
use crate::operations::{IntersectCrossingSegments, Orient};
use crate::oriented::Orientation;
use crate::relatable::Relation;
use crate::relating::event::is_event_right;
use crate::relating::utils::all_equal;
use crate::sweeping::traits::{EventsContainer, EventsQueue, SweepLine};
use crate::traits::{Elemental, Segmental};
use super::event::{
is_event_left, left_event_to_position, segment_id_to_left_event,
segment_id_to_right_event, Event,
};
use super::events_queue_key::EventsQueueKey;
use super::sweep_line_key::SweepLineKey;
pub(crate) struct Operation<Point> {
first_segments_count: usize,
#[allow(clippy::box_collection)]
endpoints: Box<Vec<Point>>,
events_queue_data: BinaryHeap<Reverse<EventsQueueKey<Point>>>,
have_interior_to_left: Vec<bool>,
#[allow(clippy::box_collection)]
opposites: Box<Vec<Event>>,
other_have_interior_to_left: Vec<bool>,
overlap_kinds: Vec<OverlapKind>,
segments_ids: Vec<usize>,
sweep_line_data: BTreeSet<SweepLineKey<Point>>,
}
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
enum EventKind {
CommonPolylineSegment,
CommonRegionEdge,
Inside,
Outside,
}
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
enum OverlapKind {
None,
SameOrientation,
DifferentOrientation,
}
struct RelationState {
boundaries_intersect: bool,
first_boundary_intersects_second_interior: bool,
first_is_subset: bool,
has_continuous_intersection: bool,
second_boundary_intersects_first_interior: bool,
second_is_subset: bool,
}
impl<Point> EventsContainer for Operation<Point> {
type Endpoint = Point;
type Event = Event;
fn get_event_end(&self, event: Self::Event) -> &Self::Endpoint {
&self.endpoints[self.to_opposite_event(event)]
}
fn get_event_start(&self, event: Self::Event) -> &Self::Endpoint {
&self.endpoints[event]
}
}
impl<Point: Ord> Operation<Point>
where
for<'a> &'a Point: Orient,
{
pub(super) fn from_segments_iterators<
First: Iterator<Item = Segment>,
Second: Iterator<Item = Segment>,
Segment: Segmental<Endpoint = Point>,
>(
(first_segments_count, first_segments): (usize, First),
(second_segments_count, second_segments): (usize, Second),
) -> Self {
let mut result =
Self::with_capacity(first_segments_count, second_segments_count);
result.extend(first_segments);
result.extend(second_segments);
result
}
}
impl<Point> Operation<Point> {
pub(super) fn into_relation<Scalar: PartialOrd>(
mut self,
first_is_subset: bool,
second_is_subset: bool,
min_max_x: &Scalar,
) -> Relation
where
Self: EventsQueue<Event = Event> + SweepLine<Event = Event>,
Point: Clone + PartialOrd,
for<'a> &'a Point: Elemental<Coordinate = &'a Scalar>
+ IntersectCrossingSegments<Output = Point>
+ Orient,
{
let mut state = RelationState {
boundaries_intersect: false,
first_boundary_intersects_second_interior: false,
first_is_subset,
second_boundary_intersects_first_interior: false,
second_is_subset,
has_continuous_intersection: false,
};
let event = unsafe { self.pop().unwrap_unchecked() };
let mut first_same_start_event = event;
let mut same_start_events = vec![event];
self.process_event(event);
loop {
if let Some(event) = self.pop() {
let start = self.get_event_start(event);
if start == self.get_event_start(first_same_start_event) {
same_start_events.push(event);
} else {
state.update(&same_start_events, &self);
same_start_events.clear();
if state.has_continuous_intersection
&& !state.first_is_subset
&& !state.second_is_subset
{
break;
}
if start.x() > min_max_x {
if self.is_event_from_first_operand(event) {
if state.first_is_subset {
state.first_is_subset = false;
}
} else if state.second_is_subset {
state.second_is_subset = false;
}
break;
}
first_same_start_event = event;
same_start_events.push(event);
}
self.process_event(event);
} else {
debug_assert!(!same_start_events.is_empty());
state.update(&same_start_events, &self);
same_start_events.clear();
break;
}
}
debug_assert!(same_start_events.is_empty());
if state.boundaries_intersect {
if state.first_is_subset {
if state.second_is_subset {
Relation::Equal
} else if state.first_boundary_intersects_second_interior {
Relation::Enclosed
} else {
Relation::Component
}
} else if state.second_is_subset {
if state.second_boundary_intersects_first_interior {
Relation::Encloses
} else {
Relation::Composite
}
} else if state.has_continuous_intersection {
Relation::Overlap
} else {
Relation::Touch
}
} else if state.second_is_subset {
Relation::Cover
} else if state.first_is_subset {
Relation::Within
} else if state.has_continuous_intersection {
Relation::Overlap
} else {
Relation::Disjoint
}
}
}
impl<Point> Operation<Point> {
fn compute_left_event_fields(
&mut self,
event: Event,
maybe_below_event: Option<Event>,
) where
for<'a> &'a Point: Elemental,
for<'a> <&'a Point as Elemental>::Coordinate: PartialEq,
{
if let Some(below_event) = maybe_below_event {
self.other_have_interior_to_left[left_event_to_position(event)] = {
if self.is_left_event_from_first_operand(event)
== self.is_left_event_from_first_operand(below_event)
{
self.other_have_interior_to_left
[left_event_to_position(below_event)]
} else {
self.have_interior_to_left
[self.left_event_to_segment_id(below_event)]
}
};
}
}
fn get_endpoints(&self) -> &Vec<Point> {
&self.endpoints
}
fn get_opposites(&self) -> &Vec<Event> {
&self.opposites
}
fn classify_event(&self, event: Event) -> EventKind {
let left_event_position =
left_event_to_position(self.to_left_event(event));
match self.overlap_kinds[left_event_position] {
OverlapKind::None => {
if self.other_have_interior_to_left[left_event_position] {
EventKind::Inside
} else {
EventKind::Outside
}
}
OverlapKind::DifferentOrientation => {
EventKind::CommonPolylineSegment
}
OverlapKind::SameOrientation => EventKind::CommonRegionEdge,
}
}
fn has_edges_cross(&self, same_start_events: &[Event]) -> bool {
let mut flags = [None, None];
for &event in same_start_events {
let left_event = self.to_left_event(event);
let left_event_position = left_event_to_position(left_event);
if self.overlap_kinds[left_event_position] == OverlapKind::None {
let flag_index =
if self.is_left_event_from_first_operand(left_event) {
1usize
} else {
0usize
};
let event_is_inside =
self.other_have_interior_to_left[left_event_position];
if let Some(previous_event_is_inside) = flags[flag_index] {
if previous_event_is_inside != event_is_inside {
return true;
}
} else {
flags[flag_index] = Some(event_is_inside);
}
}
}
false
}
fn is_event_from_first_operand(&self, event: Event) -> bool {
self.is_left_event_from_first_operand(self.to_left_event(event))
}
fn is_left_event_from_first_operand(&self, event: Event) -> bool {
self.left_event_to_segment_id(event) < self.first_segments_count
}
fn left_event_to_segment_id(&self, event: Event) -> usize {
self.segments_ids[left_event_to_position(event)]
}
fn process_event(&mut self, event: Event)
where
Self: EventsQueue<Event = Event> + SweepLine<Event = Event>,
Point: Clone + PartialOrd,
for<'a> &'a Point:
Elemental + IntersectCrossingSegments<Output = Point> + Orient,
for<'a> <&'a Point as Elemental>::Coordinate: PartialEq,
{
if is_event_right(event) {
let opposite_event = self.to_opposite_event(event);
debug_assert!(is_event_left(opposite_event));
if let Some(equal_segment_event) =
<Self as SweepLine>::find(self, opposite_event)
{
let (maybe_above_event, maybe_below_event) = (
self.above(equal_segment_event),
self.below(equal_segment_event),
);
self.remove(equal_segment_event);
if let (Some(above_event), Some(below_event)) =
(maybe_above_event, maybe_below_event)
{
self.detect_intersection(below_event, above_event);
}
}
} else if self.insert(event) {
debug_assert!(is_event_left(event));
let maybe_below_event = self.below(event);
self.compute_left_event_fields(event, maybe_below_event);
if let Some(above_event) = self.above(event) {
if self.detect_intersection(event, above_event) {
self.compute_left_event_fields(event, maybe_below_event);
self.compute_left_event_fields(above_event, Some(event));
}
}
if let Some(below_event) = maybe_below_event {
if self.detect_intersection(below_event, event) {
let below_below_event = self.below(below_event);
self.compute_left_event_fields(
below_event,
below_below_event,
);
self.compute_left_event_fields(event, maybe_below_event);
}
}
}
}
fn to_events_queue_key(&self, event: Event) -> EventsQueueKey<Point> {
EventsQueueKey::new(
event,
self.is_event_from_first_operand(event),
self.get_endpoints(),
self.get_opposites(),
)
}
fn to_left_event(&self, event: Event) -> Event {
if is_event_left(event) {
event
} else {
self.to_opposite_event(event)
}
}
fn to_opposite_event(&self, event: Event) -> Event {
self.opposites[event]
}
fn to_sweep_line_key(&self, event: Event) -> SweepLineKey<Point> {
SweepLineKey::new(
event,
self.is_left_event_from_first_operand(event),
&self.endpoints,
&self.opposites,
)
}
}
impl<Point: Clone + PartialOrd> Operation<Point>
where
Self: EventsQueue<Event = Event> + SweepLine<Event = Event>,
for<'a> &'a Point: IntersectCrossingSegments<Output = Point> + Orient,
{
fn detect_intersection(
&mut self,
below_event: Event,
event: Event,
) -> bool {
debug_assert_ne!(below_event, event);
let event_start = self.get_event_start(event);
let event_end = self.get_event_end(event);
let below_event_start = self.get_event_start(below_event);
let below_event_end = self.get_event_end(below_event);
let event_start_orientation =
below_event_end.orient(below_event_start, event_start);
let event_end_orientation =
below_event_end.orient(below_event_start, event_end);
if event_start_orientation == event_end_orientation {
if event_start_orientation == Orientation::Collinear {
debug_assert_ne!(
self.is_left_event_from_first_operand(below_event),
self.is_left_event_from_first_operand(event)
);
if event_start == below_event_start {
if event_end != below_event_end {
let (max_end_event, min_end_event) =
if event_end < below_event_end {
(below_event, event)
} else {
(event, below_event)
};
let min_end =
self.get_event_end(min_end_event).clone();
let (min_end_to_start_event, min_end_to_max_end_event) =
self.divide(max_end_event, min_end);
self.push(min_end_to_start_event);
self.push(min_end_to_max_end_event);
}
let overlap_kind = if self.have_interior_to_left
[self.left_event_to_segment_id(event)]
== self.have_interior_to_left
[self.left_event_to_segment_id(below_event)]
{
OverlapKind::SameOrientation
} else {
OverlapKind::DifferentOrientation
};
self.overlap_kinds[left_event_to_position(below_event)] =
overlap_kind;
self.overlap_kinds[left_event_to_position(event)] =
overlap_kind;
return true;
} else if event_end == below_event_end {
let (max_start_event, min_start_event) =
if event_start < below_event_start {
(below_event, event)
} else {
(event, below_event)
};
let max_start =
self.get_event_start(max_start_event).clone();
let (max_start_to_min_start_event, max_start_to_end_event) =
self.divide(min_start_event, max_start);
self.push(max_start_to_min_start_event);
self.push(max_start_to_end_event);
} else if below_event_start < event_start
&& event_start < below_event_end
{
if event_end < below_event_end {
let event_start = event_start.clone();
let event_end = event_end.clone();
self.divide_event_by_mid_segment_event_endpoints(
below_event,
event,
event_start,
event_end,
);
} else {
let (max_start, min_end) =
(event_start.clone(), below_event_end.clone());
self.divide_overlapping_events(
below_event,
event,
max_start,
min_end,
);
}
} else if event_start < below_event_start
&& below_event_start < event_end
{
if below_event_end < event_end {
let below_event_start = below_event_start.clone();
let below_event_end = below_event_end.clone();
self.divide_event_by_mid_segment_event_endpoints(
event,
below_event,
below_event_start,
below_event_end,
);
} else {
let (max_start, min_end) =
(below_event_start.clone(), event_end.clone());
self.divide_overlapping_events(
event,
below_event,
max_start,
min_end,
);
}
}
}
} else if event_start_orientation == Orientation::Collinear {
if below_event_start < event_start && event_start < below_event_end
{
let point = event_start.clone();
self.divide_event_by_midpoint(below_event, point);
}
} else if event_end_orientation == Orientation::Collinear {
if below_event_start < event_end && event_end < below_event_end {
let point = event_end.clone();
self.divide_event_by_midpoint(below_event, point);
}
} else {
let below_event_start_orientation =
event_start.orient(event_end, below_event_start);
let below_event_end_orientation =
event_start.orient(event_end, below_event_end);
if below_event_start_orientation == Orientation::Collinear {
debug_assert_ne!(
below_event_end_orientation,
Orientation::Collinear
);
if event_start < below_event_start
&& below_event_start < event_end
{
let point = below_event_start.clone();
self.divide_event_by_midpoint(event, point);
}
} else if below_event_end_orientation == Orientation::Collinear {
if event_start < below_event_end && below_event_end < event_end
{
let point = below_event_end.clone();
self.divide_event_by_midpoint(event, point);
}
} else if below_event_start_orientation
!= below_event_end_orientation
{
let cross_point =
IntersectCrossingSegments::intersect_crossing_segments(
event_start,
event_end,
below_event_start,
below_event_end,
);
self.divide_event_by_midpoint(
below_event,
cross_point.clone(),
);
self.divide_event_by_midpoint(event, cross_point);
}
}
false
}
fn divide_overlapping_events(
&mut self,
min_start_event: Event,
max_start_event: Event,
max_start: Point,
min_end: Point,
) {
self.divide_event_by_midpoint(max_start_event, min_end);
self.divide_event_by_midpoint(min_start_event, max_start);
}
fn divide_event_by_mid_segment_event_endpoints(
&mut self,
event: Event,
mid_segment_event: Event,
mid_segment_event_start: Point,
mid_segment_event_end: Point,
) where
Point: PartialEq,
{
debug_assert!(mid_segment_event_start
.eq(self.get_event_start(mid_segment_event)));
debug_assert!(
mid_segment_event_end.eq(self.get_event_end(mid_segment_event))
);
debug_assert!(mid_segment_event_start.ne(self.get_event_start(event)));
debug_assert!(mid_segment_event_end.ne(self.get_event_end(event)));
self.divide_event_by_midpoint(event, mid_segment_event_end);
self.divide_event_by_midpoint(event, mid_segment_event_start);
}
fn divide_event_by_midpoint(&mut self, event: Event, point: Point) {
let (point_to_event_start_event, point_to_event_end_event) =
self.divide(event, point);
self.push(point_to_event_start_event);
self.push(point_to_event_end_event);
}
}
impl<Point: Clone> Operation<Point> {
fn divide(&mut self, event: Event, mid_point: Point) -> (Event, Event) {
debug_assert!(is_event_left(event));
let opposite_event = self.to_opposite_event(event);
let mid_point_to_event_end_event: Event = self.endpoints.len();
self.segments_ids.push(self.left_event_to_segment_id(event));
self.endpoints.push(mid_point.clone());
self.opposites.push(opposite_event);
self.opposites[opposite_event] = mid_point_to_event_end_event;
self.other_have_interior_to_left.push(false);
self.overlap_kinds.push(OverlapKind::None);
let mid_point_to_event_start_event: Event = self.endpoints.len();
self.endpoints.push(mid_point);
self.opposites.push(event);
self.opposites[event] = mid_point_to_event_start_event;
debug_assert_eq!(
self.is_left_event_from_first_operand(event),
self.is_event_from_first_operand(mid_point_to_event_start_event)
);
debug_assert_eq!(
self.is_left_event_from_first_operand(event),
self.is_left_event_from_first_operand(
mid_point_to_event_end_event
)
);
(mid_point_to_event_start_event, mid_point_to_event_end_event)
}
}
impl<Point: Ord> EventsQueue for Operation<Point>
where
for<'a> &'a Point: Orient,
{
type Event = Event;
fn peek(&mut self) -> Option<Self::Event> {
self.events_queue_data.peek().map(|key| key.0.event)
}
fn pop(&mut self) -> Option<Self::Event> {
self.events_queue_data.pop().map(|key| key.0.event)
}
fn push(&mut self, event: Self::Event) {
self.events_queue_data
.push(Reverse(self.to_events_queue_key(event)));
}
}
impl<Point> SweepLine for Operation<Point>
where
SweepLineKey<Point>: Ord,
{
type Event = Event;
fn above(&self, event: Self::Event) -> Option<Self::Event> {
self.sweep_line_data
.range((Excluded(&self.to_sweep_line_key(event)), Unbounded))
.next()
.map(|key| key.event)
}
fn below(&self, event: Self::Event) -> Option<Self::Event> {
self.sweep_line_data
.range((Unbounded, Excluded(&self.to_sweep_line_key(event))))
.last()
.map(|key| key.event)
}
fn find(&self, event: Self::Event) -> Option<Self::Event> {
self.sweep_line_data
.get(&self.to_sweep_line_key(event))
.map(|key| key.event)
}
fn insert(&mut self, event: Self::Event) -> bool {
self.sweep_line_data.insert(self.to_sweep_line_key(event))
}
fn remove(&mut self, event: Self::Event) -> bool {
self.sweep_line_data.remove(&self.to_sweep_line_key(event))
}
}
impl<Point: Ord> Operation<Point>
where
for<'a> &'a Point: Orient,
{
fn extend<Segment>(&mut self, segments: impl Iterator<Item = Segment>)
where
Segment: Segmental<Endpoint = Point>,
{
let segment_id_offset = self.endpoints.len() / 2;
for (segment_index, segment) in segments.enumerate() {
let (mut start, mut end) = segment.endpoints();
debug_assert!(start != end);
let segment_id = segment_id_offset + segment_index;
let is_sorted_segment = start < end;
if !is_sorted_segment {
(start, end) = (end, start);
self.have_interior_to_left[segment_id] = false;
}
let left_event = segment_id_to_left_event(segment_id);
let right_event = segment_id_to_right_event(segment_id);
self.endpoints.push(start);
self.endpoints.push(end);
self.opposites.push(right_event);
self.opposites.push(left_event);
self.push(left_event);
self.push(right_event);
}
}
fn with_capacity(
first_segments_count: usize,
second_segments_count: usize,
) -> Self {
let segments_count = first_segments_count + second_segments_count;
let initial_events_count = 2 * segments_count;
Self {
first_segments_count,
endpoints: Box::new(Vec::with_capacity(initial_events_count)),
events_queue_data: BinaryHeap::with_capacity(initial_events_count),
have_interior_to_left: vec![true; segments_count],
opposites: Box::new(Vec::with_capacity(initial_events_count)),
other_have_interior_to_left: vec![false; segments_count],
overlap_kinds: vec![OverlapKind::None; segments_count],
segments_ids: (0..segments_count).collect(),
sweep_line_data: BTreeSet::new(),
}
}
}
impl RelationState {
fn update<Scalar>(
&mut self,
same_start_events: &[Event],
operation: &Operation<Scalar>,
) {
if all_equal(
same_start_events
.iter()
.map(|&event| operation.is_event_from_first_operand(event)),
) {
let event = same_start_events[0];
match operation.classify_event(event) {
EventKind::Inside => {
if !self.has_continuous_intersection {
self.has_continuous_intersection = true;
}
if operation.is_event_from_first_operand(event) {
if !self.first_boundary_intersects_second_interior {
self.first_boundary_intersects_second_interior =
true;
}
if self.second_is_subset {
self.second_is_subset = false;
}
} else {
if !self.second_boundary_intersects_first_interior {
self.second_boundary_intersects_first_interior =
true;
}
if self.first_is_subset {
self.first_is_subset = false;
}
}
}
EventKind::Outside => {
if operation.is_event_from_first_operand(event) {
if self.first_is_subset {
self.first_is_subset = false;
}
} else if self.second_is_subset {
self.second_is_subset = false;
}
}
_ => unreachable!(),
}
} else if operation.has_edges_cross(same_start_events) {
self.has_continuous_intersection = true;
self.first_is_subset = false;
self.second_is_subset = false;
} else {
if !self.boundaries_intersect {
self.boundaries_intersect = true;
}
for &event in same_start_events {
match operation.classify_event(event) {
EventKind::CommonRegionEdge => {
if !self.has_continuous_intersection {
self.has_continuous_intersection = true;
}
}
EventKind::Inside => {
if !self.has_continuous_intersection {
self.has_continuous_intersection = true;
}
if operation.is_event_from_first_operand(event) {
if !self.first_boundary_intersects_second_interior
{
self.first_boundary_intersects_second_interior = true;
}
if self.second_is_subset {
self.second_is_subset = false;
}
} else {
if !self.second_boundary_intersects_first_interior
{
self.second_boundary_intersects_first_interior = true;
}
if self.first_is_subset {
self.first_is_subset = false;
}
}
}
EventKind::Outside | EventKind::CommonPolylineSegment => {
if operation.is_event_from_first_operand(event) {
if self.first_is_subset {
self.first_is_subset = false;
}
} else if self.second_is_subset {
self.second_is_subset = false;
}
}
}
}
}
}
}