haskal
/
kicad
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
kicad/polygon/poly2tri/sweep/sweep.cc

1024 lines
27 KiB
C++
Raw Blame History

/*
* 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.
*/
#include <stdexcept>
#include "sweep.h"
#include "sweep_context.h"
#include "advancing_front.h"
#include "../common/utils.h"
namespace p2t {
// Triangulate simple polygon with holes
void Sweep::Triangulate( SweepContext& tcx )
{
tcx.InitTriangulation();
tcx.CreateAdvancingFront( nodes_ );
// Sweep points; build mesh
SweepPoints( tcx );
// Clean up
FinalizationPolygon( tcx );
}
void Sweep::SweepPoints( SweepContext& tcx )
{
for( int jj = 1; jj < tcx.point_count(); jj++ )
{
Point& point = *tcx.GetPoint( jj );
Node* node = &PointEvent( tcx, point );
for( unsigned int i = 0; i < point.edge_list.size(); i++ )
{
EdgeEvent( tcx, point.edge_list[i], node );
}
}
}
void Sweep::FinalizationPolygon( SweepContext& tcx )
{
// Get an Internal triangle to start with
Triangle* t = tcx.front()->head()->next->triangle;
Point* p = tcx.front()->head()->next->point;
while( !t->GetConstrainedEdgeCW( *p ) )
{
t = t->NeighborCCW( *p );
}
// Collect interior triangles constrained by edges
tcx.MeshClean( *t );
}
Node& Sweep::PointEvent( SweepContext& tcx, Point& point )
{
Node& node = tcx.LocateNode( point );
Node& new_node = NewFrontTriangle( tcx, point, node );
// Only need to check +epsilon since point never have smaller
// x value than node due to how we fetch nodes from the front
if( point.x <= node.point->x + EPSILON )
{
Fill( tcx, node );
}
// tcx.AddNode(new_node);
FillAdvancingFront( tcx, new_node );
return new_node;
}
void Sweep::EdgeEvent( SweepContext& tcx, Edge* edge, Node* node )
{
tcx.edge_event.constrained_edge = edge;
tcx.edge_event.right = (edge->p->x > edge->q->x);
if( IsEdgeSideOfTriangle( *node->triangle, *edge->p, *edge->q ) )
{
return;
}
// For now we will do all needed filling
// TODO: integrate with flip process might give some better performance
// but for now this avoid the issue with cases that needs both flips and fills
FillEdgeEvent( tcx, edge, node );
EdgeEvent( tcx, *edge->p, *edge->q, node->triangle, *edge->q );
}
void Sweep::EdgeEvent( SweepContext& tcx, Point& ep, Point& eq, Triangle* triangle, Point& point )
{
if( IsEdgeSideOfTriangle( *triangle, ep, eq ) )
{
return;
}
Point* p1 = triangle->PointCCW( point );
Orientation o1 = Orient2d( eq, *p1, ep );
if( o1 == COLLINEAR )
{
if( triangle->Contains( &eq, p1 ) )
{
triangle->MarkConstrainedEdge( &eq, p1 );
// We are modifying the constraint maybe it would be better to
// not change the given constraint and just keep a variable for the new constraint
tcx.edge_event.constrained_edge->q = p1;
triangle = &triangle->NeighborAcross( point );
EdgeEvent( tcx, ep, *p1, triangle, *p1 );
}
else
{
std::runtime_error( "EdgeEvent - collinear points not supported" );
assert( 0 );
}
return;
}
Point* p2 = triangle->PointCW( point );
Orientation o2 = Orient2d( eq, *p2, ep );
if( o2 == COLLINEAR )
{
if( triangle->Contains( &eq, p2 ) )
{
triangle->MarkConstrainedEdge( &eq, p2 );
// We are modifying the constraint maybe it would be better to
// not change the given constraint and just keep a variable for the new constraint
tcx.edge_event.constrained_edge->q = p2;
triangle = &triangle->NeighborAcross( point );
EdgeEvent( tcx, ep, *p2, triangle, *p2 );
}
else
{
std::runtime_error( "EdgeEvent - collinear points not supported" );
assert( 0 );
}
return;
}
if( o1 == o2 )
{
// Need to decide if we are rotating CW or CCW to get to a triangle
// that will cross edge
if( o1 == CW )
{
triangle = triangle->NeighborCCW( point );
}
else
{
triangle = triangle->NeighborCW( point );
}
EdgeEvent( tcx, ep, eq, triangle, point );
}
else
{
// This triangle crosses constraint so lets flippin start!
FlipEdgeEvent( tcx, ep, eq, triangle, point );
}
}
bool Sweep::IsEdgeSideOfTriangle( Triangle& triangle, Point& ep, Point& eq )
{
int index = triangle.EdgeIndex( &ep, &eq );
if( index != -1 )
{
triangle.MarkConstrainedEdge( index );
Triangle* t = triangle.GetNeighbor( index );
if( t )
{
t->MarkConstrainedEdge( &ep, &eq );
}
return true;
}
return false;
}
Node& Sweep::NewFrontTriangle( SweepContext& tcx, Point& point, Node& node )
{
Triangle* triangle = new Triangle( point, *node.point, *node.next->point );
triangle->MarkNeighbor( *node.triangle );
tcx.AddToMap( triangle );
Node* new_node = new Node( point );
nodes_.push_back( new_node );
new_node->next = node.next;
new_node->prev = &node;
node.next->prev = new_node;
node.next = new_node;
if( !Legalize( tcx, *triangle ) )
{
tcx.MapTriangleToNodes( *triangle );
}
return *new_node;
}
void Sweep::Fill( SweepContext& tcx, Node& node )
{
Triangle* triangle = new Triangle( *node.prev->point, *node.point, *node.next->point );
// TODO: should copy the constrained_edge value from neighbor triangles
// for now constrained_edge values are copied during the legalize
triangle->MarkNeighbor( *node.prev->triangle );
triangle->MarkNeighbor( *node.triangle );
tcx.AddToMap( triangle );
// Update the advancing front
node.prev->next = node.next;
node.next->prev = node.prev;
// If it was legalized the triangle has already been mapped
if( !Legalize( tcx, *triangle ) )
{
tcx.MapTriangleToNodes( *triangle );
}
}
void Sweep::FillAdvancingFront( SweepContext& tcx, Node& n )
{
// Fill right holes
Node* node = n.next;
while( node->next )
{
// if HoleAngle exceeds 90 degrees then break.
if( LargeHole_DontFill( node ) )
break;
Fill( tcx, *node );
node = node->next;
}
// Fill left holes
node = n.prev;
while( node->prev )
{
// if HoleAngle exceeds 90 degrees then break.
if( LargeHole_DontFill( node ) )
break;
Fill( tcx, *node );
node = node->prev;
}
// Fill right basins
if( n.next && n.next->next )
{
double angle = BasinAngle( n );
if( angle < PI_3div4 )
{
FillBasin( tcx, n );
}
}
}
// True if HoleAngle exceeds 90 degrees.
bool Sweep::LargeHole_DontFill( Node* node )
{
Node* nextNode = node->next;
Node* prevNode = node->prev;
if( !AngleExceeds90Degrees( node->point, nextNode->point, prevNode->point ) )
return false;
// Check additional points on front.
Node* next2Node = nextNode->next;
// "..Plus.." because only want angles on same side as point being added.
if( (next2Node != NULL)
&& !AngleExceedsPlus90DegreesOrIsNegative( node->point, next2Node->point,
prevNode->point ) )
return false;
Node* prev2Node = prevNode->prev;
// "..Plus.." because only want angles on same side as point being added.
if( (prev2Node != NULL)
&& !AngleExceedsPlus90DegreesOrIsNegative( node->point, nextNode->point,
prev2Node->point ) )
return false;
return true;
}
bool Sweep::AngleExceeds90Degrees( Point* origin, Point* pa, Point* pb )
{
double angle = Angle( *origin, *pa, *pb );
bool exceeds90Degrees = ( (angle > PI_div2) || (angle < -PI_div2) );
return exceeds90Degrees;
}
bool Sweep::AngleExceedsPlus90DegreesOrIsNegative( Point* origin, Point* pa, Point* pb )
{
double angle = Angle( *origin, *pa, *pb );
bool exceedsPlus90DegreesOrIsNegative = (angle > PI_div2) || (angle < 0);
return exceedsPlus90DegreesOrIsNegative;
}
double Sweep::Angle( Point& origin, Point& pa, Point& pb )
{
/* Complex plane
* ab = cosA +i*sinA
* ab = (ax + ay*i)(bx + by*i) = (ax*bx + ay*by) + i(ax*by-ay*bx)
* atan2(y,x) computes the principal value of the argument function
* applied to the complex number x+iy
* Where x = ax*bx + ay*by
* y = ax*by - ay*bx
*/
double px = origin.x;
double py = origin.y;
double ax = pa.x - px;
double ay = pa.y - py;
double bx = pb.x - px;
double by = pb.y - py;
double x = ax * by - ay * bx;
double y = ax * bx + ay * by;
double angle = atan2( x, y );
return angle;
}
double Sweep::BasinAngle( Node& node )
{
double ax = node.point->x - node.next->next->point->x;
double ay = node.point->y - node.next->next->point->y;
return atan2( ay, ax );
}
double Sweep::HoleAngle( Node& node )
{
/* Complex plane
* ab = cosA +i*sinA
* ab = (ax + ay*i)(bx + by*i) = (ax*bx + ay*by) + i(ax*by-ay*bx)
* atan2(y,x) computes the principal value of the argument function
* applied to the complex number x+iy
* Where x = ax*bx + ay*by
* y = ax*by - ay*bx
*/
double ax = node.next->point->x - node.point->x;
double ay = node.next->point->y - node.point->y;
double bx = node.prev->point->x - node.point->x;
double by = node.prev->point->y - node.point->y;
return atan2( ax * by - ay * bx, ax * bx + ay * by );
}
bool Sweep::Legalize( SweepContext& tcx, Triangle& t )
{
// To legalize a triangle we start by finding if any of the three edges
// 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( Point& pa, Point& pb, Point& pc, Point& pd )
{
double adx = pa.x - pd.x;
double ady = pa.y - pd.y;
double bdx = pb.x - pd.x;
double bdy = pb.y - pd.y;
double adxbdy = adx * bdy;
double bdxady = bdx * ady;
double oabd = adxbdy - bdxady;
if( oabd <= 0 )
return false;
double cdx = pc.x - pd.x;
double cdy = pc.y - pd.y;
double cdxady = cdx * ady;
double adxcdy = adx * cdy;
double ocad = cdxady - adxcdy;
if( ocad <= 0 )
return false;
double bdxcdy = bdx * cdy;
double cdxbdy = cdx * bdy;
double alift = adx * adx + ady * ady;
double blift = bdx * bdx + bdy * bdy;
double clift = cdx * cdx + cdy * cdy;
double det = alift * (bdxcdy - cdxbdy) + blift * ocad + clift * oabd;
return det > 0;
}
void Sweep::RotateTrianglePair( Triangle& t, Point& p, Triangle& ot, Point& op )
{
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 );
}
else
{
// 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 );
}
else
{
// Convex
// Next above or below edge?
if( Orient2d( *edge->q, *node.next->next->point, *edge->p ) == CCW )
{
// Below
FillRightConvexEdgeEvent( tcx, edge, *node.next );
}
else
{
// 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 );
}
else
{
// Convex
// Next above or below edge?
if( Orient2d( *edge->q, *node.prev->prev->point, *edge->p ) == CW )
{
// Below
FillLeftConvexEdgeEvent( tcx, edge, *node.prev );
}
else
{
// 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 );
}
else
{
// Next is convex
}
}
}
}
void Sweep::FlipEdgeEvent( SweepContext& tcx, Point& ep, Point& eq, Triangle* t, Point& p )
{
Triangle& ot = t->NeighborAcross( p );
Point& op = *ot.OppositePoint( *t, p );
if( &ot == NULL )
{
// If we want to integrate the fillEdgeEvent do it here
// With current implementation we should never get here
// throw new RuntimeException( "[BUG:FIXME] FLIP failed due to missing triangle");
assert( 0 );
}
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 new RuntimeException("[Unsupported] Opposing point on constrained edge");
assert( 0 );
// Never executed, due tu assert( 0 ). Just to avoid compil warning
return ep;
}
void Sweep::FlipScanEdgeEvent( SweepContext& tcx, Point& ep, Point& eq, Triangle& flip_triangle,
Triangle& t, Point& p )
{
Triangle& ot = t.NeighborAcross( p );
Point& op = *ot.OppositePoint( t, p );
if( &t.NeighborAcross( p ) == NULL )
{
// If we want to integrate the fillEdgeEvent do it here
// With current implementation we should never get here
// throw new RuntimeException( "[BUG:FIXME] FLIP failed due to missing triangle");
assert( 0 );
}
if( InScanArea( eq, *flip_triangle.PointCCW( eq ), *flip_triangle.PointCW( eq ), op ) )
{
// 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.
}
else
{
Point& newP = NextFlipPoint( ep, eq, ot, op );
FlipScanEdgeEvent( tcx, ep, eq, flip_triangle, ot, newP );
}
}
Sweep::~Sweep()
{
// Clean up memory
for( unsigned i = 0; i < nodes_.size(); i++ )
{
delete nodes_[i];
}
}
}
Reference in New Issue View Git Blame Copy Permalink