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kicad/polygon/poly2tri/sweep/sweep.h

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/*
* Poly2Tri Copyright (c) 2009-2010, Poly2Tri Contributors
* http://code.google.com/p/poly2tri/
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* * Neither the name of Poly2Tri nor the names of its contributors may be
* used to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* Sweep-line, Constrained Delauney Triangulation (CDT) See: Domiter, V. and
* Zalik, B.(2008)'Sweep-line algorithm for constrained Delaunay triangulation',
* International Journal of Geographical Information Science
*
* "FlipScan" Constrained Edge Algorithm invented by Thomas Åhlén, thahlen@gmail.com
*/
#ifndef SWEEP_H
#define SWEEP_H
#include <vector>
namespace p2t {
class SweepContext;
struct Node;
struct Point;
struct Edge;
class Triangle;
class Sweep
{
public:
/**
* Triangulate
*
* @param tcx
*/
void Triangulate(SweepContext& tcx);
/**
* Destructor - clean up memory
*/
~Sweep();
private:
/**
* Start sweeping the Y-sorted point set from bottom to top
*
* @param tcx
*/
void SweepPoints(SweepContext& tcx);
/**
* Find closes node to the left of the new point and
* create a new triangle. If needed new holes and basins
* will be filled to.
*
* @param tcx
* @param point
* @return
*/
Node& PointEvent(SweepContext& tcx, Point& point);
/**
*
*
* @param tcx
* @param edge
* @param node
*/
void EdgeEvent(SweepContext& tcx, Edge* edge, Node* node);
void EdgeEvent(SweepContext& tcx, Point& ep, Point& eq, Triangle* triangle, Point& point);
/**
* Creates a new front triangle and legalize it
*
* @param tcx
* @param point
* @param node
* @return
*/
Node& NewFrontTriangle(SweepContext& tcx, Point& point, Node& node);
/**
* Adds a triangle to the advancing front to fill a hole.
* @param tcx
* @param node - middle node, that is the bottom of the hole
*/
void Fill(SweepContext& tcx, Node& node);
/**
* Returns true if triangle was legalized
*/
bool Legalize(SweepContext& tcx, Triangle& t);
/**
* <b>Requirement</b>:<br>
* 1. a,b and c form a triangle.<br>
* 2. a and d is know to be on opposite side of bc<br>
* <pre>
* a
* +
* / \
* / \
* b/ \c
* +-------+
* / d \
* / \
* </pre>
* <b>Fact</b>: d has to be in area B to have a chance to be inside the circle formed by
* a,b and c<br>
* d is outside B if orient2d(a,b,d) or orient2d(c,a,d) is CW<br>
* This preknowledge gives us a way to optimize the incircle test
* @param a - triangle point, opposite d
* @param b - triangle point
* @param c - triangle point
* @param d - point opposite a
* @return true if d is inside circle, false if on circle edge
*/
bool Incircle(Point& pa, Point& pb, Point& pc, Point& pd);
/**
* Rotates a triangle pair one vertex CW
*<pre>
* n2 n2
* P +-----+ P +-----+
* | t /| |\ t |
* | / | | \ |
* n1| / |n3 n1| \ |n3
* | / | after CW | \ |
* |/ oT | | oT \|
* +-----+ oP +-----+
* n4 n4
* </pre>
*/
void RotateTrianglePair(Triangle& t, Point& p, Triangle& ot, Point& op);
/**
* Fills holes in the Advancing Front
*
*
* @param tcx
* @param n
*/
void FillAdvancingFront(SweepContext& tcx, Node& n);
// Decision-making about when to Fill hole.
// Contributed by ToolmakerSteve2
bool LargeHole_DontFill(Node* node);
bool AngleExceeds90Degrees(Point* origin, Point* pa, Point* pb);
bool AngleExceedsPlus90DegreesOrIsNegative(Point* origin, Point* pa, Point* pb);
double Angle(Point& origin, Point& pa, Point& pb);
/**
*
* @param node - middle node
* @return the angle between 3 front nodes
*/
double HoleAngle(Node& node);
/**
* The basin angle is decided against the horizontal line [1,0]
*/
double BasinAngle(Node& node);
/**
* Fills a basin that has formed on the Advancing Front to the right
* of given node.<br>
* First we decide a left,bottom and right node that forms the
* boundaries of the basin. Then we do a reqursive fill.
*
* @param tcx
* @param node - starting node, this or next node will be left node
*/
void FillBasin(SweepContext& tcx, Node& node);
/**
* Recursive algorithm to fill a Basin with triangles
*
* @param tcx
* @param node - bottom_node
* @param cnt - counter used to alternate on even and odd numbers
*/
void FillBasinReq(SweepContext& tcx, Node* node);
bool IsShallow(SweepContext& tcx, Node& node);
bool IsEdgeSideOfTriangle(Triangle& triangle, Point& ep, Point& eq);
void FillEdgeEvent(SweepContext& tcx, Edge* edge, Node* node);
void FillRightAboveEdgeEvent(SweepContext& tcx, Edge* edge, Node* node);
void FillRightBelowEdgeEvent(SweepContext& tcx, Edge* edge, Node& node);
void FillRightConcaveEdgeEvent(SweepContext& tcx, Edge* edge, Node& node);
void FillRightConvexEdgeEvent(SweepContext& tcx, Edge* edge, Node& node);
void FillLeftAboveEdgeEvent(SweepContext& tcx, Edge* edge, Node* node);
void FillLeftBelowEdgeEvent(SweepContext& tcx, Edge* edge, Node& node);
void FillLeftConcaveEdgeEvent(SweepContext& tcx, Edge* edge, Node& node);
void FillLeftConvexEdgeEvent(SweepContext& tcx, Edge* edge, Node& node);
void FlipEdgeEvent(SweepContext& tcx, Point& ep, Point& eq, Triangle* t, Point& p);
/**
* After a flip we have two triangles and know that only one will still be
* intersecting the edge. So decide which to contiune with and legalize the other
*
* @param tcx
* @param o - should be the result of an orient2d( eq, op, ep )
* @param t - triangle 1
* @param ot - triangle 2
* @param p - a point shared by both triangles
* @param op - another point shared by both triangles
* @return returns the triangle still intersecting the edge
*/
Triangle& NextFlipTriangle(SweepContext& tcx, int o, Triangle& t, Triangle& ot, Point& p, Point& op);
/**
* When we need to traverse from one triangle to the next we need
* the point in current triangle that is the opposite point to the next
* triangle.
*
* @param ep
* @param eq
* @param ot
* @param op
* @return
*/
Point& NextFlipPoint(Point& ep, Point& eq, Triangle& ot, Point& op);
/**
* Scan part of the FlipScan algorithm<br>
* When a triangle pair isn't flippable we will scan for the next
* point that is inside the flip triangle scan area. When found
* we generate a new flipEdgeEvent
*
* @param tcx
* @param ep - last point on the edge we are traversing
* @param eq - first point on the edge we are traversing
* @param flipTriangle - the current triangle sharing the point eq with edge
* @param t
* @param p
*/
void FlipScanEdgeEvent(SweepContext& tcx, Point& ep, Point& eq, Triangle& flip_triangle, Triangle& t, Point& p);
void FinalizationPolygon(SweepContext& tcx);
std::vector<Node*> nodes_;
};
}
#endif
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