netgen/libsrc/geom2d/csg2d.hpp

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2020-08-19 19:46:32 +05:00
#ifndef NETGEN_CSG2D_HPP_INCLUDED
#define NETGEN_CSG2D_HPP_INCLUDED
#include "geometry2d.hpp"
namespace netgen
{
using namespace ngcore;
using netgen::Point;
using netgen::Vec;
inline double Area(const Point<2>& P, const Point<2>& Q, const Point<2>& R)
{
return (Q[0]-P[0]) * (R[1]-P[1]) - (Q[1]-P[1]) * (R[0]-P[0]);
}
enum IntersectionType
{ // types of intersection (detected in the first phase)
NO_INTERSECTION = 0,
X_INTERSECTION,
T_INTERSECTION_Q,
T_INTERSECTION_P,
V_INTERSECTION,
X_OVERLAP,
T_OVERLAP_Q,
T_OVERLAP_P,
V_OVERLAP
};
enum IntersectionLabel
{ // for the classification of intersection vertices in the second phase
NONE,
CROSSING,
BOUNCING,
LEFT_ON,
RIGHT_ON,
ON_ON,
ON_LEFT,
ON_RIGHT,
DELAYED_CROSSING,
DELAYED_BOUNCING
};
enum EntryExitLabel
{ // for marking intersection vertices as "entry" or "exit"
EXIT,
ENTRY,
NEITHER
};
enum IteratorType
{
SOURCE,
INTERSECTION,
CROSSING_INTERSECTION,
ALL
};
using Spline = SplineSeg3<2>;
struct Vertex : Point<2>
{
Vertex (Point<2> p) : Point<2>(p) {}
Vertex * prev = nullptr;
Vertex * next = nullptr;
unique_ptr<Vertex> pnext = nullptr;
Vertex * neighbour = nullptr; // same vertex in other polygon (at intersections)
double lam = -1.0;
bool is_intersection = false;
bool is_source = false;
IntersectionLabel label = NONE; // type of intersection vertex
EntryExitLabel enex = NEITHER; // entry/exit "flag"
string bc = "";
// In case the edge this - next is curved, store the spline information here
optional<Spline> spline = nullopt;
Vertex * Insert(Point<2> p, double lam = -1.0);
void Link( Vertex * v )
{
neighbour = v;
v->neighbour = this;
is_intersection = true;
v->is_intersection = true;
}
};
struct VertexIterator
{
struct iterator
{
iterator(Vertex* root, IteratorType IterType) :
root(root), V(NULL), iterType(IterType)
{
if (root == NULL)
return;
if (nextVertex() == NULL) // no (source/intersection) vertex found
root = V = NULL; // -> mark iterator as "end"
}
const iterator& operator++()
{
nextVertex();
return *this;
}
Vertex* operator*()
{
return V;
}
bool operator!=(const iterator& other) const
{
return (root != other.root) || (V != other.V);
}
private:
Vertex* root;
Vertex* V;
IteratorType iterType;
//
// find the next vertex
// if iterType is ALL, then it is just the next vertex
// if iterType is SOURCE, then it is the next source vertex
// if iterType is INTERSECTION, then it is the next intersection vertex
// if iterType is CROSSING_INTERSECTION, then it is the next intersection vertex with CROSSING label
//
Vertex* nextVertex()
{
bool nextFound = false;
if (V == NULL)
{ // find first (source/intersection) vertex
V = root;
switch(iterType)
{
case ALL:
nextFound = true;
break;
case SOURCE:
if (V->is_source)
nextFound = true;
break;
case INTERSECTION:
if (V->is_intersection)
nextFound = true;
break;
case CROSSING_INTERSECTION:
if (V->is_intersection && (V->label == CROSSING))
nextFound = true;
break;
}
}
while (!nextFound)
{ // find next (source/intersection) vertex
switch(iterType)
{
case ALL:
V = V->next;
break;
case SOURCE:
do {
V = V->next;
} while (!V->is_source && V != root);
break;
case INTERSECTION:
do {
V = V->next;
} while (!V->is_intersection && V != root);
break;
case CROSSING_INTERSECTION:
do {
V = V->next;
} while ( ( !V->is_intersection || (V->label != CROSSING) ) && V != root);
break;
}
if (V == root)
{ // back at the root vertex?
root = V = NULL; // -> mark iterator as "end"
return(V);
}
switch(iterType)
{
case ALL:
nextFound = true;
break;
case SOURCE:
if (V->is_source)
nextFound = true;
break;
case INTERSECTION:
if (V->is_intersection)
nextFound = true;
break;
case CROSSING_INTERSECTION:
if (V->is_intersection && (V->label == CROSSING))
nextFound = true;
break;
}
}
return(V);
}
};
public:
VertexIterator() : root(NULL) {};
iterator begin() { return iterator(root, iterType); }
iterator end() { return iterator(NULL, iterType); }
Vertex* root;
IteratorType iterType;
};
struct Edge
{
Vertex * v0 = nullptr;
Vertex * v1 = nullptr;
Edge (Vertex* v, Vertex* w) : v0(v), v1(w) { };
};
struct EdgeIterator
{
struct iterator
{
iterator(Vertex* root, IteratorType IterType) :
root(root), one(NULL), two(NULL), iterType(IterType)
{
if (root == NULL)
return;
if (nextEdge() == NULL) // no source edge found
root = one = two = NULL; // -> mark iterator as "end"
}
const iterator& operator++() { nextEdge(); return *this; }
Edge operator*()
{
return Edge(one,two);
}
bool operator!=(const iterator& other) const
{
return (root != other.root) || (one != other.one) || (two != other.two);
}
private:
Vertex* root;
Vertex* one;
Vertex* two;
IteratorType iterType;
//
// find the next vertex, starting at curr
// if iterType is ALL, then it is just the next vertex
// if iterType is SOURCE, then it is the next source vertex
//
Vertex* nextVertex(Vertex* curr)
{
if (curr == NULL)
return(NULL);
switch(iterType)
{
case ALL:
curr = curr->next;
break;
case SOURCE:
do {
curr = curr->next;
} while (!curr->is_source);
break;
default:
;
}
return(curr);
}
//
// find the next edge
//
Vertex* nextEdge()
{
if (root == NULL) // empty polygon?
return (NULL);
if (one == NULL)
{ // find one (source) vertex
one = root; // note: root is always a (source) vertex
two = nextVertex(one);
if (two == one) // just one (source) vertex
return(NULL); // -> no (source) edges
return(one);
}
if (two == root)
{ // back at the root vertex?
root = one = two = NULL; // -> mark iterator as "end"
return(NULL);
}
one = two;
two = nextVertex(one);
return (one);
}
};
public:
EdgeIterator() : root(NULL) {};
iterator begin() { return iterator(root, iterType); }
iterator end() { return iterator(NULL, iterType); }
Vertex* root;
IteratorType iterType;
};
inline int CalcSide( const Point<2> & p0, const Point<2> & p1, const Point<2> & r )
{
if ( (p0[1] < r[1]) != (p1[1] < r[1]) )
{
if (p0[0] >= r[0])
{
if (p1[0] > r[0])
return 2 * (p1[1] > p0[1]) - 1;
else
if ( (Area(p0,p1,r) > 0) == (p1[1] > p0[1]) )
return 2 * (p1[1] > p0[1]) - 1;
}
else
{
if (p1[0] > r[0])
if ( (Area(p0,p1,r) > 0) == (p1[1] > p0[1]) )
return 2 * (p1[1] > p0[1]) - 1;
}
}
return 0;
}
struct Polygon2d
{
unique_ptr<Vertex> first = nullptr;
Polygon2d() = default;
Polygon2d(const Polygon2d & p)
: first(nullptr)
{
for(auto v : p.Vertices(ALL))
AppendVertex(*v);
}
Polygon2d & operator=(const Polygon2d & p)
{
first = nullptr;
if(p.first)
for(const auto v : p.Vertices(ALL))
AppendVertex(*v);
return *this;
}
Vertex & AppendVertex(const Vertex & v)
{
auto & vnew = Append( static_cast<Point<2>>(v), true );
vnew.bc = v.bc;
if(v.spline)
vnew.spline = *v.spline;
return vnew;
}
Vertex & Append(Point<2> p, bool source = false)
{
Vertex * vnew;
if(first==nullptr)
{
first = make_unique<Vertex>(p);
first->next = first.get();
first->prev = first.get();
vnew = first.get();
}
else
{
vnew = first->prev->Insert(p);
}
vnew->is_source = source;
// cout << "size after " << Size() << endl;
return *vnew;
}
void Remove (Vertex* v)
{
v->prev->next = v->next;
v->next->prev = v->prev;
if(first.get() == v)
first = std::move(v->pnext);
else
v->prev->pnext = std::move(v->pnext);
}
bool IsInside( Point<2> r ) const
{
int w = 0;
for(auto e : Edges(ALL))
w += CalcSide(*e.v0, *e.v1, r);
return ( (w % 2) != 0 );
}
EdgeIterator Edges(IteratorType iterType) const
{
EdgeIterator it;
it.iterType = iterType;
it.root = first.get();
return it;
}
VertexIterator Vertices(IteratorType iterType, Vertex* first_ = nullptr) const
{
VertexIterator it;
it.iterType = iterType;
it.root = (first_ == nullptr) ? first.get() : first_;
return it;
}
//
// check, if all vertices have the ON_ON label
//
bool allOnOn()
{
for (Vertex* v : Vertices(ALL))
if (v->label != ON_ON)
return(false);
return(true);
}
//
// check, if the polygon does not contain any crossing intersection vertex
// or crossing intersection chain or (if we want to compute the union instead
// of the intersection) a bouncing vertex or a bouncing intersection chain
//
bool noCrossingVertex(bool union_case = false)
{
for (Vertex* v : Vertices(ALL))
if (v->is_intersection)
{
if ( (v->label == CROSSING) || (v->label == DELAYED_CROSSING) )
return(false);
if (union_case && ( (v->label == BOUNCING) || (v->label == DELAYED_BOUNCING) ) )
return(false);
}
return(true);
}
//
// return a non-intersection point
//
Point<2> getNonIntersectionPoint()
{
for (Vertex* v : Vertices(ALL))
if (!v->is_intersection)
return *v;
// no non-intersection vertex found -> find suitable edge midpoint
for (Vertex* v : Vertices(ALL))
// make sure that edge from V to V->next is not collinear with other polygon
if ( (v->next->neighbour != v->neighbour->prev) && (v->next->neighbour != v->neighbour->next) )
// return edge midpoint
return Center(*v, *v->next);
throw Exception("no point found");
}
//
// return and insert a non-intersection vertex
//
Vertex* getNonIntersectionVertex()
{
for (Vertex* v : Vertices(ALL))
if (!v->is_intersection)
return(v);
// no non-intersection vertex found -> generate and return temporary vertex
for (Vertex* v : Vertices(ALL))
// make sure that edge from V to V->next is not collinear with other polygon
if ( (v->next->neighbour != v->neighbour->prev) && (v->next->neighbour != v->neighbour->next) )
{
// add edge midpoint as temporary vertex
auto p = Center(*v, *v->next);
return v->Insert(p);
}
return(NULL);
}
void SetBC(string bc)
{
for(auto v : Vertices(ALL))
v->bc = bc;
}
size_t Size() const
{
if(first==nullptr) return 0;
size_t cnt = 0;
for(auto v : Vertices(ALL))
cnt++;
return cnt;
}
};
struct Solid2d
{
Array<Polygon2d> polys;
string name = "";
Solid2d() = default;
Solid2d(string name_) : name(name_) {}
Solid2d operator+(Solid2d & other);
Solid2d operator*(Solid2d & other);
Solid2d operator-(Solid2d other);
void Append( const Polygon2d & poly )
{
polys.Append(poly);
}
bool IsInside( Point<2> r ) const;
bool IsLeftInside( const Vertex & p0 );
bool IsRightInside( const Vertex & p0 );
void SetBC(string bc)
{
for(auto & p : polys)
for(auto v : p.Vertices(ALL))
v->bc = bc;
}
};
class CSG2d
{
public:
Array<Solid2d> solids;
void Add ( Solid2d s )
{
solids.Append(s);
}
shared_ptr<netgen::SplineGeometry2d> GenerateSplineGeometry();
};
Solid2d Circle(double x, double y, double r, string name="", string bc="");
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Solid2d Rectangle(double x0, double x1, double y0, double y1, string name, string bc);
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Solid2d AddIntersectionPoints ( Solid2d s1, Solid2d s2 );
Solid2d ClipSolids ( Solid2d s1, Solid2d s2, bool intersect=true );
}
#endif // NETGEN_CSG2D_HPP_INCLUDED