This class can triangulate a convex or concave polygon, even one with holes. More...
#include "triangulator.h"
Public Member Functions | |
void | add_hole_vertex (int index) |
Adds the next consecutive vertex of the current hole. More... | |
void | add_polygon_vertex (int index) |
Adds the next consecutive vertex of the polygon. More... | |
int | add_vertex (const LPoint2d &point) |
Adds a new vertex to the vertex pool. More... | |
int | add_vertex (double x, double y) |
Adds a new vertex to the vertex pool. More... | |
void | begin_hole () |
Finishes the previous hole, if any, and prepares to add a new hole. More... | |
void | clear () |
Removes all vertices and polygon specifications from the Triangulator, and prepares it to start over. More... | |
void | clear_polygon () |
Removes the current polygon definition (and its set of holes), but does not clear the vertex pool. More... | |
int | get_num_triangles () const |
Returns the number of triangles generated by the previous call to triangulate(). More... | |
int | get_num_vertices () const |
int | get_triangle_v0 (int n) const |
Returns vertex 0 of the nth triangle generated by the previous call to triangulate(). More... | |
int | get_triangle_v1 (int n) const |
Returns vertex 1 of the nth triangle generated by the previous call to triangulate(). More... | |
int | get_triangle_v2 (int n) const |
Returns vertex 2 of the nth triangle generated by the previous call to triangulate(). More... | |
const LPoint2d & | get_vertex (int n) const |
bool | is_left_winding () const |
Returns true if the polygon vertices are listed in counterclockwise order, or false if they appear to be listed in clockwise order. More... | |
void | triangulate () |
Does the work of triangulating the specified polygon. More... | |
Public Attributes | |
get_num_vertices | |
Returns the number of vertices in the pool. More... | |
get_vertex | |
Returns the nth vertex. More... | |
Friends | |
struct | segment_t |
class | Triangle |
This class can triangulate a convex or concave polygon, even one with holes.
It is adapted from an algorithm published as:
Narkhede A. and Manocha D., Fast polygon triangulation algorithm based on Seidel's Algorithm, UNC-CH, 1994.
http://www.cs.unc.edu/~dm/CODE/GEM/chapter.html
It works strictly on 2-d points. See Triangulator3 for 3-d points.
Definition at line 32 of file triangulator.h.
void Triangulator::add_hole_vertex | ( | int | index | ) |
Adds the next consecutive vertex of the current hole.
This vertex should index into the vertex pool established by repeated calls to add_vertex().
The vertices may be listed in either clockwise or counterclockwise order. Vertices should not be repeated.
Definition at line 83 of file triangulator.cxx.
void Triangulator::add_polygon_vertex | ( | int | index | ) |
Adds the next consecutive vertex of the polygon.
This vertex should index into the vertex pool established by repeated calls to add_vertex().
The vertices may be listed in either clockwise or counterclockwise order. Vertices should not be repeated. In particular, do not repeat the first vertex at the end.
Definition at line 63 of file triangulator.cxx.
int Triangulator::add_vertex | ( | const LPoint2d & | point | ) |
Adds a new vertex to the vertex pool.
Returns the vertex index number.
Definition at line 38 of file triangulator.cxx.
Referenced by add_vertex().
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inline |
Adds a new vertex to the vertex pool.
Returns the vertex index number.
Definition at line 18 of file triangulator.I.
References add_vertex().
void Triangulator::begin_hole | ( | ) |
Finishes the previous hole, if any, and prepares to add a new hole.
Definition at line 71 of file triangulator.cxx.
void Triangulator::clear | ( | ) |
Removes all vertices and polygon specifications from the Triangulator, and prepares it to start over.
Definition at line 29 of file triangulator.cxx.
References clear_polygon().
Referenced by Triangulator3::clear().
void Triangulator::clear_polygon | ( | ) |
Removes the current polygon definition (and its set of holes), but does not clear the vertex pool.
Definition at line 49 of file triangulator.cxx.
Referenced by clear().
int Triangulator::get_num_triangles | ( | ) | const |
Returns the number of triangles generated by the previous call to triangulate().
Definition at line 206 of file triangulator.cxx.
int Triangulator::get_triangle_v0 | ( | int | n | ) | const |
Returns vertex 0 of the nth triangle generated by the previous call to triangulate().
This is a zero-based index into the vertices added by repeated calls to add_vertex().
Definition at line 218 of file triangulator.cxx.
int Triangulator::get_triangle_v1 | ( | int | n | ) | const |
Returns vertex 1 of the nth triangle generated by the previous call to triangulate().
This is a zero-based index into the vertices added by repeated calls to add_vertex().
Definition at line 231 of file triangulator.cxx.
int Triangulator::get_triangle_v2 | ( | int | n | ) | const |
Returns vertex 2 of the nth triangle generated by the previous call to triangulate().
This is a zero-based index into the vertices added by repeated calls to add_vertex().
Definition at line 244 of file triangulator.cxx.
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inline |
Returns true if the polygon vertices are listed in counterclockwise order, or false if they appear to be listed in clockwise order.
Definition at line 47 of file triangulator.I.
void Triangulator::triangulate | ( | ) |
Does the work of triangulating the specified polygon.
After this call, you may retrieve the new triangles one at a time by iterating through get_triangle_v0/1/2().
Definition at line 94 of file triangulator.cxx.
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inline |
Returns the number of vertices in the pool.
Note that the Triangulator might append new vertices, in addition to those added by the user, if any of the polygon is self-intersecting, or if any of the holes intersect some part of the polygon edges.
Definition at line 42 of file triangulator.h.
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inline |
Returns the nth vertex.
Definition at line 42 of file triangulator.h.