2020-11-16 14:47:43 +08:00
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/*
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* Poly2Tri Copyright (c) 2009-2018, Poly2Tri Contributors
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* https://github.com/jhasse/poly2tri
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* * Neither the name of Poly2Tri nor the names of its contributors may be
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* used to endorse or promote products derived from this software without specific
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* prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "sweep.h"
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#include "sweep_context.h"
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#include "advancing_front.h"
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#include "../common/utils.h"
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#include <cassert>
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#include <stdexcept>
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namespace p2t {
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// Triangulate simple polygon with holes
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void Sweep::Triangulate(SweepContext& tcx)
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{
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tcx.InitTriangulation();
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tcx.CreateAdvancingFront();
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// Sweep points; build mesh
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SweepPoints(tcx);
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// Clean up
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FinalizationPolygon(tcx);
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}
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void Sweep::SweepPoints(SweepContext& tcx)
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{
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for (size_t i = 1; i < tcx.point_count(); i++) {
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Point& point = *tcx.GetPoint(i);
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Node* node = &PointEvent(tcx, point);
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2022-04-29 15:36:16 +08:00
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for (auto& j : point.edge_list) {
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EdgeEvent(tcx, j, node);
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2020-11-16 14:47:43 +08:00
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}
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}
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}
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void Sweep::FinalizationPolygon(SweepContext& tcx)
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{
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// Get an Internal triangle to start with
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Triangle* t = tcx.front()->head()->next->triangle;
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Point* p = tcx.front()->head()->next->point;
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2021-06-01 11:47:19 +08:00
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while (t && !t->GetConstrainedEdgeCW(*p)) {
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2020-11-16 14:47:43 +08:00
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t = t->NeighborCCW(*p);
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}
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// Collect interior triangles constrained by edges
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2021-06-01 11:47:19 +08:00
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if (t) {
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tcx.MeshClean(*t);
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}
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2020-11-16 14:47:43 +08:00
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}
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Node& Sweep::PointEvent(SweepContext& tcx, Point& point)
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{
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2021-06-01 11:47:19 +08:00
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Node* node_ptr = tcx.LocateNode(point);
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if (!node_ptr || !node_ptr->point || !node_ptr->next || !node_ptr->next->point)
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{
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throw std::runtime_error("PointEvent - null node");
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}
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Node& node = *node_ptr;
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2020-11-16 14:47:43 +08:00
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Node& new_node = NewFrontTriangle(tcx, point, node);
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// Only need to check +epsilon since point never have smaller
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// x value than node due to how we fetch nodes from the front
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if (point.x <= node.point->x + EPSILON) {
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Fill(tcx, node);
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}
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//tcx.AddNode(new_node);
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FillAdvancingFront(tcx, new_node);
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return new_node;
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}
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void Sweep::EdgeEvent(SweepContext& tcx, Edge* edge, Node* node)
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{
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tcx.edge_event.constrained_edge = edge;
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tcx.edge_event.right = (edge->p->x > edge->q->x);
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if (IsEdgeSideOfTriangle(*node->triangle, *edge->p, *edge->q)) {
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return;
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}
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// For now we will do all needed filling
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// TODO: integrate with flip process might give some better performance
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// but for now this avoid the issue with cases that needs both flips and fills
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FillEdgeEvent(tcx, edge, node);
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EdgeEvent(tcx, *edge->p, *edge->q, node->triangle, *edge->q);
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}
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void Sweep::EdgeEvent(SweepContext& tcx, Point& ep, Point& eq, Triangle* triangle, Point& point)
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{
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if (triangle == nullptr) {
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throw std::runtime_error("EdgeEvent - null triangle");
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}
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2020-11-16 14:47:43 +08:00
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if (IsEdgeSideOfTriangle(*triangle, ep, eq)) {
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return;
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}
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Point* p1 = triangle->PointCCW(point);
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Orientation o1 = Orient2d(eq, *p1, ep);
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if (o1 == COLLINEAR) {
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2021-06-01 11:47:19 +08:00
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if (triangle->Contains(&eq, p1)) {
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triangle->MarkConstrainedEdge(&eq, p1);
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2020-11-16 14:47:43 +08:00
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// We are modifying the constraint maybe it would be better to
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// not change the given constraint and just keep a variable for the new constraint
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tcx.edge_event.constrained_edge->q = p1;
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2021-06-01 11:47:19 +08:00
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triangle = triangle->NeighborAcross(point);
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EdgeEvent(tcx, ep, *p1, triangle, *p1);
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2020-11-16 14:47:43 +08:00
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} else {
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throw std::runtime_error("EdgeEvent - collinear points not supported");
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}
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return;
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}
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Point* p2 = triangle->PointCW(point);
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Orientation o2 = Orient2d(eq, *p2, ep);
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if (o2 == COLLINEAR) {
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2021-06-01 11:47:19 +08:00
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if (triangle->Contains(&eq, p2)) {
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triangle->MarkConstrainedEdge(&eq, p2);
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2020-11-16 14:47:43 +08:00
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// We are modifying the constraint maybe it would be better to
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// not change the given constraint and just keep a variable for the new constraint
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tcx.edge_event.constrained_edge->q = p2;
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2021-06-01 11:47:19 +08:00
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triangle = triangle->NeighborAcross(point);
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EdgeEvent(tcx, ep, *p2, triangle, *p2);
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2020-11-16 14:47:43 +08:00
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} else {
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throw std::runtime_error("EdgeEvent - collinear points not supported");
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}
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return;
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}
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if (o1 == o2) {
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// Need to decide if we are rotating CW or CCW to get to a triangle
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// that will cross edge
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if (o1 == CW) {
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triangle = triangle->NeighborCCW(point);
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2021-06-01 11:47:19 +08:00
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} else {
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2020-11-16 14:47:43 +08:00
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triangle = triangle->NeighborCW(point);
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}
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EdgeEvent(tcx, ep, eq, triangle, point);
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} else {
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// This triangle crosses constraint so lets flippin start!
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2021-06-01 11:47:19 +08:00
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assert(triangle);
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2020-11-16 14:47:43 +08:00
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FlipEdgeEvent(tcx, ep, eq, triangle, point);
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}
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}
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bool Sweep::IsEdgeSideOfTriangle(Triangle& triangle, Point& ep, Point& eq)
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{
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const int index = triangle.EdgeIndex(&ep, &eq);
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if (index != -1) {
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triangle.MarkConstrainedEdge(index);
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Triangle* t = triangle.GetNeighbor(index);
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if (t) {
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t->MarkConstrainedEdge(&ep, &eq);
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}
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return true;
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}
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return false;
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}
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Node& Sweep::NewFrontTriangle(SweepContext& tcx, Point& point, Node& node)
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{
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Triangle* triangle = new Triangle(point, *node.point, *node.next->point);
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triangle->MarkNeighbor(*node.triangle);
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tcx.AddToMap(triangle);
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Node* new_node = new Node(point);
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nodes_.push_back(new_node);
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new_node->next = node.next;
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new_node->prev = &node;
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node.next->prev = new_node;
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node.next = new_node;
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if (!Legalize(tcx, *triangle)) {
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tcx.MapTriangleToNodes(*triangle);
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}
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return *new_node;
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}
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void Sweep::Fill(SweepContext& tcx, Node& node)
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{
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Triangle* triangle = new Triangle(*node.prev->point, *node.point, *node.next->point);
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// TODO: should copy the constrained_edge value from neighbor triangles
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// for now constrained_edge values are copied during the legalize
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triangle->MarkNeighbor(*node.prev->triangle);
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triangle->MarkNeighbor(*node.triangle);
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tcx.AddToMap(triangle);
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// Update the advancing front
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node.prev->next = node.next;
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node.next->prev = node.prev;
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// If it was legalized the triangle has already been mapped
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if (!Legalize(tcx, *triangle)) {
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tcx.MapTriangleToNodes(*triangle);
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}
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}
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void Sweep::FillAdvancingFront(SweepContext& tcx, Node& n)
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{
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// Fill right holes
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Node* node = n.next;
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2021-06-01 11:47:19 +08:00
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while (node && node->next) {
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2020-11-16 14:47:43 +08:00
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// if HoleAngle exceeds 90 degrees then break.
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if (LargeHole_DontFill(node)) break;
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Fill(tcx, *node);
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node = node->next;
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}
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// Fill left holes
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node = n.prev;
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2021-06-01 11:47:19 +08:00
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while (node && node->prev) {
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2020-11-16 14:47:43 +08:00
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// if HoleAngle exceeds 90 degrees then break.
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if (LargeHole_DontFill(node)) break;
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Fill(tcx, *node);
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node = node->prev;
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}
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// Fill right basins
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if (n.next && n.next->next) {
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const double angle = BasinAngle(n);
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if (angle < PI_3div4) {
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FillBasin(tcx, n);
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}
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}
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}
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// True if HoleAngle exceeds 90 degrees.
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bool Sweep::LargeHole_DontFill(const Node* node) const {
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const Node* nextNode = node->next;
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const Node* prevNode = node->prev;
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if (!AngleExceeds90Degrees(node->point, nextNode->point, prevNode->point))
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return false;
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// Check additional points on front.
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const Node* next2Node = nextNode->next;
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// "..Plus.." because only want angles on same side as point being added.
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if ((next2Node != nullptr) && !AngleExceedsPlus90DegreesOrIsNegative(node->point, next2Node->point, prevNode->point))
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return false;
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const Node* prev2Node = prevNode->prev;
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// "..Plus.." because only want angles on same side as point being added.
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if ((prev2Node != nullptr) && !AngleExceedsPlus90DegreesOrIsNegative(node->point, nextNode->point, prev2Node->point))
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return false;
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return true;
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}
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bool Sweep::AngleExceeds90Degrees(const Point* origin, const Point* pa, const Point* pb) const {
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const double angle = Angle(origin, pa, pb);
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return ((angle > PI_div2) || (angle < -PI_div2));
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}
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bool Sweep::AngleExceedsPlus90DegreesOrIsNegative(const Point* origin, const Point* pa, const Point* pb) const {
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const double angle = Angle(origin, pa, pb);
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return (angle > PI_div2) || (angle < 0);
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}
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double Sweep::Angle(const Point* origin, const Point* pa, const Point* pb) const {
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/* Complex plane
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* ab = cosA +i*sinA
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* ab = (ax + ay*i)(bx + by*i) = (ax*bx + ay*by) + i(ax*by-ay*bx)
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* atan2(y,x) computes the principal value of the argument function
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* applied to the complex number x+iy
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* Where x = ax*bx + ay*by
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* y = ax*by - ay*bx
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*/
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const double px = origin->x;
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const double py = origin->y;
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const double ax = pa->x - px;
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2020-11-16 14:47:43 +08:00
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const double ay = pa->y - py;
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const double bx = pb->x - px;
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const double by = pb->y - py;
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const double x = ax * by - ay * bx;
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const double y = ax * bx + ay * by;
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return atan2(x, y);
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}
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double Sweep::BasinAngle(const Node& node) const
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{
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const double ax = node.point->x - node.next->next->point->x;
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const double ay = node.point->y - node.next->next->point->y;
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return atan2(ay, ax);
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}
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double Sweep::HoleAngle(const Node& node) const
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{
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/* Complex plane
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* ab = cosA +i*sinA
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* ab = (ax + ay*i)(bx + by*i) = (ax*bx + ay*by) + i(ax*by-ay*bx)
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* atan2(y,x) computes the principal value of the argument function
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* applied to the complex number x+iy
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* Where x = ax*bx + ay*by
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* y = ax*by - ay*bx
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*/
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const double ax = node.next->point->x - node.point->x;
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const double ay = node.next->point->y - node.point->y;
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const double bx = node.prev->point->x - node.point->x;
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const double by = node.prev->point->y - node.point->y;
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return atan2(ax * by - ay * bx, ax * bx + ay * by);
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}
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bool Sweep::Legalize(SweepContext& tcx, Triangle& t)
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{
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// To legalize a triangle we start by finding if any of the three edges
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// violate the Delaunay condition
|
|
|
|
for (int i = 0; i < 3; i++) {
|
|
|
|
if (t.delaunay_edge[i])
|
|
|
|
continue;
|
|
|
|
|
|
|
|
Triangle* ot = t.GetNeighbor(i);
|
|
|
|
|
|
|
|
if (ot) {
|
|
|
|
Point* p = t.GetPoint(i);
|
|
|
|
Point* op = ot->OppositePoint(t, *p);
|
|
|
|
int oi = ot->Index(op);
|
|
|
|
|
|
|
|
// If this is a Constrained Edge or a Delaunay Edge(only during recursive legalization)
|
|
|
|
// then we should not try to legalize
|
|
|
|
if (ot->constrained_edge[oi] || ot->delaunay_edge[oi]) {
|
|
|
|
t.constrained_edge[i] = ot->constrained_edge[oi];
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
bool inside = Incircle(*p, *t.PointCCW(*p), *t.PointCW(*p), *op);
|
|
|
|
|
|
|
|
if (inside) {
|
|
|
|
// Lets mark this shared edge as Delaunay
|
|
|
|
t.delaunay_edge[i] = true;
|
|
|
|
ot->delaunay_edge[oi] = true;
|
|
|
|
|
|
|
|
// Lets rotate shared edge one vertex CW to legalize it
|
|
|
|
RotateTrianglePair(t, *p, *ot, *op);
|
|
|
|
|
|
|
|
// We now got one valid Delaunay Edge shared by two triangles
|
|
|
|
// This gives us 4 new edges to check for Delaunay
|
|
|
|
|
|
|
|
// Make sure that triangle to node mapping is done only one time for a specific triangle
|
|
|
|
bool not_legalized = !Legalize(tcx, t);
|
|
|
|
if (not_legalized) {
|
|
|
|
tcx.MapTriangleToNodes(t);
|
|
|
|
}
|
|
|
|
|
|
|
|
not_legalized = !Legalize(tcx, *ot);
|
|
|
|
if (not_legalized)
|
|
|
|
tcx.MapTriangleToNodes(*ot);
|
|
|
|
|
|
|
|
// Reset the Delaunay edges, since they only are valid Delaunay edges
|
|
|
|
// until we add a new triangle or point.
|
|
|
|
// XXX: need to think about this. Can these edges be tried after we
|
|
|
|
// return to previous recursive level?
|
|
|
|
t.delaunay_edge[i] = false;
|
|
|
|
ot->delaunay_edge[oi] = false;
|
|
|
|
|
|
|
|
// If triangle have been legalized no need to check the other edges since
|
|
|
|
// the recursive legalization will handles those so we can end here.
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
|
|
|
|
bool Sweep::Incircle(const Point& pa, const Point& pb, const Point& pc, const Point& pd) const
|
|
|
|
{
|
|
|
|
const double adx = pa.x - pd.x;
|
|
|
|
const double ady = pa.y - pd.y;
|
|
|
|
const double bdx = pb.x - pd.x;
|
|
|
|
const double bdy = pb.y - pd.y;
|
|
|
|
|
|
|
|
const double adxbdy = adx * bdy;
|
|
|
|
const double bdxady = bdx * ady;
|
|
|
|
const double oabd = adxbdy - bdxady;
|
|
|
|
|
|
|
|
if (oabd <= 0)
|
|
|
|
return false;
|
|
|
|
|
|
|
|
const double cdx = pc.x - pd.x;
|
|
|
|
const double cdy = pc.y - pd.y;
|
|
|
|
|
|
|
|
const double cdxady = cdx * ady;
|
|
|
|
const double adxcdy = adx * cdy;
|
|
|
|
const double ocad = cdxady - adxcdy;
|
|
|
|
|
|
|
|
if (ocad <= 0)
|
|
|
|
return false;
|
|
|
|
|
|
|
|
const double bdxcdy = bdx * cdy;
|
|
|
|
const double cdxbdy = cdx * bdy;
|
|
|
|
|
|
|
|
const double alift = adx * adx + ady * ady;
|
|
|
|
const double blift = bdx * bdx + bdy * bdy;
|
|
|
|
const double clift = cdx * cdx + cdy * cdy;
|
|
|
|
|
|
|
|
const double det = alift * (bdxcdy - cdxbdy) + blift * ocad + clift * oabd;
|
|
|
|
|
|
|
|
return det > 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
void Sweep::RotateTrianglePair(Triangle& t, Point& p, Triangle& ot, Point& op) const
|
|
|
|
{
|
|
|
|
Triangle* n1, *n2, *n3, *n4;
|
|
|
|
n1 = t.NeighborCCW(p);
|
|
|
|
n2 = t.NeighborCW(p);
|
|
|
|
n3 = ot.NeighborCCW(op);
|
|
|
|
n4 = ot.NeighborCW(op);
|
|
|
|
|
|
|
|
bool ce1, ce2, ce3, ce4;
|
|
|
|
ce1 = t.GetConstrainedEdgeCCW(p);
|
|
|
|
ce2 = t.GetConstrainedEdgeCW(p);
|
|
|
|
ce3 = ot.GetConstrainedEdgeCCW(op);
|
|
|
|
ce4 = ot.GetConstrainedEdgeCW(op);
|
|
|
|
|
|
|
|
bool de1, de2, de3, de4;
|
|
|
|
de1 = t.GetDelunayEdgeCCW(p);
|
|
|
|
de2 = t.GetDelunayEdgeCW(p);
|
|
|
|
de3 = ot.GetDelunayEdgeCCW(op);
|
|
|
|
de4 = ot.GetDelunayEdgeCW(op);
|
|
|
|
|
|
|
|
t.Legalize(p, op);
|
|
|
|
ot.Legalize(op, p);
|
|
|
|
|
|
|
|
// Remap delaunay_edge
|
|
|
|
ot.SetDelunayEdgeCCW(p, de1);
|
|
|
|
t.SetDelunayEdgeCW(p, de2);
|
|
|
|
t.SetDelunayEdgeCCW(op, de3);
|
|
|
|
ot.SetDelunayEdgeCW(op, de4);
|
|
|
|
|
|
|
|
// Remap constrained_edge
|
|
|
|
ot.SetConstrainedEdgeCCW(p, ce1);
|
|
|
|
t.SetConstrainedEdgeCW(p, ce2);
|
|
|
|
t.SetConstrainedEdgeCCW(op, ce3);
|
|
|
|
ot.SetConstrainedEdgeCW(op, ce4);
|
|
|
|
|
|
|
|
// Remap neighbors
|
|
|
|
// XXX: might optimize the markNeighbor by keeping track of
|
|
|
|
// what side should be assigned to what neighbor after the
|
|
|
|
// rotation. Now mark neighbor does lots of testing to find
|
|
|
|
// the right side.
|
|
|
|
t.ClearNeighbors();
|
|
|
|
ot.ClearNeighbors();
|
|
|
|
if (n1) ot.MarkNeighbor(*n1);
|
|
|
|
if (n2) t.MarkNeighbor(*n2);
|
|
|
|
if (n3) t.MarkNeighbor(*n3);
|
|
|
|
if (n4) ot.MarkNeighbor(*n4);
|
|
|
|
t.MarkNeighbor(ot);
|
|
|
|
}
|
|
|
|
|
|
|
|
void Sweep::FillBasin(SweepContext& tcx, Node& node)
|
|
|
|
{
|
|
|
|
if (Orient2d(*node.point, *node.next->point, *node.next->next->point) == CCW) {
|
|
|
|
tcx.basin.left_node = node.next->next;
|
|
|
|
} else {
|
|
|
|
tcx.basin.left_node = node.next;
|
|
|
|
}
|
|
|
|
|
|
|
|
// Find the bottom and right node
|
|
|
|
tcx.basin.bottom_node = tcx.basin.left_node;
|
|
|
|
while (tcx.basin.bottom_node->next
|
|
|
|
&& tcx.basin.bottom_node->point->y >= tcx.basin.bottom_node->next->point->y) {
|
|
|
|
tcx.basin.bottom_node = tcx.basin.bottom_node->next;
|
|
|
|
}
|
|
|
|
if (tcx.basin.bottom_node == tcx.basin.left_node) {
|
|
|
|
// No valid basin
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
tcx.basin.right_node = tcx.basin.bottom_node;
|
|
|
|
while (tcx.basin.right_node->next
|
|
|
|
&& tcx.basin.right_node->point->y < tcx.basin.right_node->next->point->y) {
|
|
|
|
tcx.basin.right_node = tcx.basin.right_node->next;
|
|
|
|
}
|
|
|
|
if (tcx.basin.right_node == tcx.basin.bottom_node) {
|
|
|
|
// No valid basins
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
tcx.basin.width = tcx.basin.right_node->point->x - tcx.basin.left_node->point->x;
|
|
|
|
tcx.basin.left_highest = tcx.basin.left_node->point->y > tcx.basin.right_node->point->y;
|
|
|
|
|
|
|
|
FillBasinReq(tcx, tcx.basin.bottom_node);
|
|
|
|
}
|
|
|
|
|
|
|
|
void Sweep::FillBasinReq(SweepContext& tcx, Node* node)
|
|
|
|
{
|
|
|
|
// if shallow stop filling
|
|
|
|
if (IsShallow(tcx, *node)) {
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
Fill(tcx, *node);
|
|
|
|
|
|
|
|
if (node->prev == tcx.basin.left_node && node->next == tcx.basin.right_node) {
|
|
|
|
return;
|
|
|
|
} else if (node->prev == tcx.basin.left_node) {
|
|
|
|
Orientation o = Orient2d(*node->point, *node->next->point, *node->next->next->point);
|
|
|
|
if (o == CW) {
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
node = node->next;
|
|
|
|
} else if (node->next == tcx.basin.right_node) {
|
|
|
|
Orientation o = Orient2d(*node->point, *node->prev->point, *node->prev->prev->point);
|
|
|
|
if (o == CCW) {
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
node = node->prev;
|
|
|
|
} else {
|
|
|
|
// Continue with the neighbor node with lowest Y value
|
|
|
|
if (node->prev->point->y < node->next->point->y) {
|
|
|
|
node = node->prev;
|
|
|
|
} else {
|
|
|
|
node = node->next;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
FillBasinReq(tcx, node);
|
|
|
|
}
|
|
|
|
|
|
|
|
bool Sweep::IsShallow(SweepContext& tcx, Node& node)
|
|
|
|
{
|
|
|
|
double height;
|
|
|
|
|
|
|
|
if (tcx.basin.left_highest) {
|
|
|
|
height = tcx.basin.left_node->point->y - node.point->y;
|
|
|
|
} else {
|
|
|
|
height = tcx.basin.right_node->point->y - node.point->y;
|
|
|
|
}
|
|
|
|
|
|
|
|
// if shallow stop filling
|
|
|
|
if (tcx.basin.width > height) {
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
|
|
|
|
void Sweep::FillEdgeEvent(SweepContext& tcx, Edge* edge, Node* node)
|
|
|
|
{
|
|
|
|
if (tcx.edge_event.right) {
|
|
|
|
FillRightAboveEdgeEvent(tcx, edge, node);
|
|
|
|
} else {
|
|
|
|
FillLeftAboveEdgeEvent(tcx, edge, node);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void Sweep::FillRightAboveEdgeEvent(SweepContext& tcx, Edge* edge, Node* node)
|
|
|
|
{
|
|
|
|
while (node->next->point->x < edge->p->x) {
|
|
|
|
// Check if next node is below the edge
|
|
|
|
if (Orient2d(*edge->q, *node->next->point, *edge->p) == CCW) {
|
|
|
|
FillRightBelowEdgeEvent(tcx, edge, *node);
|
|
|
|
} else {
|
|
|
|
node = node->next;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void Sweep::FillRightBelowEdgeEvent(SweepContext& tcx, Edge* edge, Node& node)
|
|
|
|
{
|
|
|
|
if (node.point->x < edge->p->x) {
|
|
|
|
if (Orient2d(*node.point, *node.next->point, *node.next->next->point) == CCW) {
|
|
|
|
// Concave
|
|
|
|
FillRightConcaveEdgeEvent(tcx, edge, node);
|
2021-06-01 11:47:19 +08:00
|
|
|
} else {
|
2020-11-16 14:47:43 +08:00
|
|
|
// Convex
|
|
|
|
FillRightConvexEdgeEvent(tcx, edge, node);
|
|
|
|
// Retry this one
|
|
|
|
FillRightBelowEdgeEvent(tcx, edge, node);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void Sweep::FillRightConcaveEdgeEvent(SweepContext& tcx, Edge* edge, Node& node)
|
|
|
|
{
|
|
|
|
Fill(tcx, *node.next);
|
|
|
|
if (node.next->point != edge->p) {
|
|
|
|
// Next above or below edge?
|
|
|
|
if (Orient2d(*edge->q, *node.next->point, *edge->p) == CCW) {
|
|
|
|
// Below
|
|
|
|
if (Orient2d(*node.point, *node.next->point, *node.next->next->point) == CCW) {
|
|
|
|
// Next is concave
|
|
|
|
FillRightConcaveEdgeEvent(tcx, edge, node);
|
|
|
|
} else {
|
|
|
|
// Next is convex
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void Sweep::FillRightConvexEdgeEvent(SweepContext& tcx, Edge* edge, Node& node)
|
|
|
|
{
|
|
|
|
// Next concave or convex?
|
|
|
|
if (Orient2d(*node.next->point, *node.next->next->point, *node.next->next->next->point) == CCW) {
|
|
|
|
// Concave
|
|
|
|
FillRightConcaveEdgeEvent(tcx, edge, *node.next);
|
2021-06-01 11:47:19 +08:00
|
|
|
} else {
|
2020-11-16 14:47:43 +08:00
|
|
|
// Convex
|
|
|
|
// Next above or below edge?
|
|
|
|
if (Orient2d(*edge->q, *node.next->next->point, *edge->p) == CCW) {
|
|
|
|
// Below
|
|
|
|
FillRightConvexEdgeEvent(tcx, edge, *node.next);
|
2021-06-01 11:47:19 +08:00
|
|
|
} else {
|
2020-11-16 14:47:43 +08:00
|
|
|
// Above
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void Sweep::FillLeftAboveEdgeEvent(SweepContext& tcx, Edge* edge, Node* node)
|
|
|
|
{
|
|
|
|
while (node->prev->point->x > edge->p->x) {
|
|
|
|
// Check if next node is below the edge
|
|
|
|
if (Orient2d(*edge->q, *node->prev->point, *edge->p) == CW) {
|
|
|
|
FillLeftBelowEdgeEvent(tcx, edge, *node);
|
|
|
|
} else {
|
|
|
|
node = node->prev;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void Sweep::FillLeftBelowEdgeEvent(SweepContext& tcx, Edge* edge, Node& node)
|
|
|
|
{
|
|
|
|
if (node.point->x > edge->p->x) {
|
|
|
|
if (Orient2d(*node.point, *node.prev->point, *node.prev->prev->point) == CW) {
|
|
|
|
// Concave
|
|
|
|
FillLeftConcaveEdgeEvent(tcx, edge, node);
|
|
|
|
} else {
|
|
|
|
// Convex
|
|
|
|
FillLeftConvexEdgeEvent(tcx, edge, node);
|
|
|
|
// Retry this one
|
|
|
|
FillLeftBelowEdgeEvent(tcx, edge, node);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void Sweep::FillLeftConvexEdgeEvent(SweepContext& tcx, Edge* edge, Node& node)
|
|
|
|
{
|
|
|
|
// Next concave or convex?
|
|
|
|
if (Orient2d(*node.prev->point, *node.prev->prev->point, *node.prev->prev->prev->point) == CW) {
|
|
|
|
// Concave
|
|
|
|
FillLeftConcaveEdgeEvent(tcx, edge, *node.prev);
|
2021-06-01 11:47:19 +08:00
|
|
|
} else {
|
2020-11-16 14:47:43 +08:00
|
|
|
// Convex
|
|
|
|
// Next above or below edge?
|
|
|
|
if (Orient2d(*edge->q, *node.prev->prev->point, *edge->p) == CW) {
|
|
|
|
// Below
|
|
|
|
FillLeftConvexEdgeEvent(tcx, edge, *node.prev);
|
2021-06-01 11:47:19 +08:00
|
|
|
} else {
|
2020-11-16 14:47:43 +08:00
|
|
|
// Above
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void Sweep::FillLeftConcaveEdgeEvent(SweepContext& tcx, Edge* edge, Node& node)
|
|
|
|
{
|
|
|
|
Fill(tcx, *node.prev);
|
|
|
|
if (node.prev->point != edge->p) {
|
|
|
|
// Next above or below edge?
|
|
|
|
if (Orient2d(*edge->q, *node.prev->point, *edge->p) == CW) {
|
|
|
|
// Below
|
|
|
|
if (Orient2d(*node.point, *node.prev->point, *node.prev->prev->point) == CW) {
|
|
|
|
// Next is concave
|
|
|
|
FillLeftConcaveEdgeEvent(tcx, edge, node);
|
2021-06-01 11:47:19 +08:00
|
|
|
} else {
|
2020-11-16 14:47:43 +08:00
|
|
|
// Next is convex
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void Sweep::FlipEdgeEvent(SweepContext& tcx, Point& ep, Point& eq, Triangle* t, Point& p)
|
|
|
|
{
|
2021-06-01 11:47:19 +08:00
|
|
|
assert(t);
|
|
|
|
Triangle* ot_ptr = t->NeighborAcross(p);
|
|
|
|
if (ot_ptr == nullptr)
|
|
|
|
{
|
|
|
|
throw std::runtime_error("FlipEdgeEvent - null neighbor across");
|
|
|
|
}
|
|
|
|
Triangle& ot = *ot_ptr;
|
2020-11-16 14:47:43 +08:00
|
|
|
Point& op = *ot.OppositePoint(*t, p);
|
|
|
|
|
|
|
|
if (InScanArea(p, *t->PointCCW(p), *t->PointCW(p), op)) {
|
|
|
|
// Lets rotate shared edge one vertex CW
|
|
|
|
RotateTrianglePair(*t, p, ot, op);
|
|
|
|
tcx.MapTriangleToNodes(*t);
|
|
|
|
tcx.MapTriangleToNodes(ot);
|
|
|
|
|
|
|
|
if (p == eq && op == ep) {
|
|
|
|
if (eq == *tcx.edge_event.constrained_edge->q && ep == *tcx.edge_event.constrained_edge->p) {
|
|
|
|
t->MarkConstrainedEdge(&ep, &eq);
|
|
|
|
ot.MarkConstrainedEdge(&ep, &eq);
|
|
|
|
Legalize(tcx, *t);
|
|
|
|
Legalize(tcx, ot);
|
|
|
|
} else {
|
|
|
|
// XXX: I think one of the triangles should be legalized here?
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
Orientation o = Orient2d(eq, op, ep);
|
|
|
|
t = &NextFlipTriangle(tcx, (int)o, *t, ot, p, op);
|
|
|
|
FlipEdgeEvent(tcx, ep, eq, t, p);
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
Point& newP = NextFlipPoint(ep, eq, ot, op);
|
|
|
|
FlipScanEdgeEvent(tcx, ep, eq, *t, ot, newP);
|
|
|
|
EdgeEvent(tcx, ep, eq, t, p);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
Triangle& Sweep::NextFlipTriangle(SweepContext& tcx, int o, Triangle& t, Triangle& ot, Point& p, Point& op)
|
|
|
|
{
|
|
|
|
if (o == CCW) {
|
|
|
|
// ot is not crossing edge after flip
|
|
|
|
int edge_index = ot.EdgeIndex(&p, &op);
|
|
|
|
ot.delaunay_edge[edge_index] = true;
|
|
|
|
Legalize(tcx, ot);
|
|
|
|
ot.ClearDelunayEdges();
|
|
|
|
return t;
|
|
|
|
}
|
|
|
|
|
|
|
|
// t is not crossing edge after flip
|
|
|
|
int edge_index = t.EdgeIndex(&p, &op);
|
|
|
|
|
|
|
|
t.delaunay_edge[edge_index] = true;
|
|
|
|
Legalize(tcx, t);
|
|
|
|
t.ClearDelunayEdges();
|
|
|
|
return ot;
|
|
|
|
}
|
|
|
|
|
|
|
|
Point& Sweep::NextFlipPoint(Point& ep, Point& eq, Triangle& ot, Point& op)
|
|
|
|
{
|
|
|
|
Orientation o2d = Orient2d(eq, op, ep);
|
|
|
|
if (o2d == CW) {
|
|
|
|
// Right
|
|
|
|
return *ot.PointCCW(op);
|
|
|
|
} else if (o2d == CCW) {
|
|
|
|
// Left
|
|
|
|
return *ot.PointCW(op);
|
|
|
|
}
|
|
|
|
throw std::runtime_error("[Unsupported] Opposing point on constrained edge");
|
|
|
|
}
|
|
|
|
|
|
|
|
void Sweep::FlipScanEdgeEvent(SweepContext& tcx, Point& ep, Point& eq, Triangle& flip_triangle,
|
|
|
|
Triangle& t, Point& p)
|
|
|
|
{
|
2021-06-01 11:47:19 +08:00
|
|
|
Triangle* ot_ptr = t.NeighborAcross(p);
|
|
|
|
if (ot_ptr == nullptr) {
|
|
|
|
throw std::runtime_error("FlipScanEdgeEvent - null neighbor across");
|
|
|
|
}
|
|
|
|
|
|
|
|
Point* op_ptr = ot_ptr->OppositePoint(t, p);
|
|
|
|
if (op_ptr == nullptr) {
|
|
|
|
throw std::runtime_error("FlipScanEdgeEvent - null opposing point");
|
|
|
|
}
|
2020-11-16 14:47:43 +08:00
|
|
|
|
2021-06-01 11:47:19 +08:00
|
|
|
Point* p1 = flip_triangle.PointCCW(eq);
|
|
|
|
Point* p2 = flip_triangle.PointCW(eq);
|
|
|
|
if (p1 == nullptr || p2 == nullptr) {
|
|
|
|
throw std::runtime_error("FlipScanEdgeEvent - null on either of points");
|
|
|
|
}
|
|
|
|
|
|
|
|
Triangle& ot = *ot_ptr;
|
|
|
|
Point& op = *op_ptr;
|
|
|
|
|
|
|
|
if (InScanArea(eq, *p1, *p2, op)) {
|
2020-11-16 14:47:43 +08:00
|
|
|
// flip with new edge op->eq
|
|
|
|
FlipEdgeEvent(tcx, eq, op, &ot, op);
|
|
|
|
// TODO: Actually I just figured out that it should be possible to
|
|
|
|
// improve this by getting the next ot and op before the the above
|
|
|
|
// flip and continue the flipScanEdgeEvent here
|
|
|
|
// set new ot and op here and loop back to inScanArea test
|
|
|
|
// also need to set a new flip_triangle first
|
|
|
|
// Turns out at first glance that this is somewhat complicated
|
|
|
|
// so it will have to wait.
|
2021-06-01 11:47:19 +08:00
|
|
|
} else {
|
2020-11-16 14:47:43 +08:00
|
|
|
Point& newP = NextFlipPoint(ep, eq, ot, op);
|
|
|
|
FlipScanEdgeEvent(tcx, ep, eq, flip_triangle, ot, newP);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
Sweep::~Sweep() {
|
|
|
|
|
|
|
|
// Clean up memory
|
2022-04-29 15:36:16 +08:00
|
|
|
for (auto& node : nodes_) {
|
|
|
|
delete node;
|
2020-11-16 14:47:43 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2021-06-01 11:47:19 +08:00
|
|
|
} // namespace p2t
|