79 lines
2.6 KiB
C
79 lines
2.6 KiB
C
/*
|
|
Header File of the Triangulation Library
|
|
|
|
This triangulation library is an implementation of a fast polygon
|
|
triangulation algorithm based on the paper ''A simple and fast
|
|
incremental randomized algorithm for computing trapezoidal
|
|
decompositions and for triangulating polygons'' by Raimund Seidel.
|
|
|
|
The algorithm handles simple polygons with holes. The input is
|
|
specified as contours. The outermost contour is anti-clockwise, while
|
|
all the inner contours must be clockwise. No point should be repeated
|
|
in the input.
|
|
|
|
The output is a list of triangles. Each triangle gives a pair
|
|
(i, j, k) where i, j, and k are indices of the vertices specified in
|
|
the input array. (The index numbering starts from 1, since the first
|
|
location v[0] in the input array of vertices is unused). The number of
|
|
output triangles produced for a polygon with n points is, (n - 2) + 2(nr of holes).
|
|
|
|
*/
|
|
|
|
#ifndef __interface_h
|
|
#define __interface_h
|
|
|
|
#define TRUE 1
|
|
#define FALSE 0
|
|
|
|
extern "C" int triangulate_polygon(int ncontours,
|
|
int cntr[],
|
|
double (*vertices)[2],
|
|
int (*triangles)[3]);
|
|
|
|
/*
|
|
Input specified as contours.
|
|
Outer contour must be anti-clockwise.
|
|
All inner contours must be clockwise.
|
|
|
|
Every contour is specified by giving all its points in order. No
|
|
point shoud be repeated. i.e. if the outer contour is a square,
|
|
only the four distinct endpoints shopudl be specified in order.
|
|
|
|
ncontours: nr of contours
|
|
cntr: An array describing the number of points in each
|
|
contour. Thus, cntr[i] = nr of points in the i'th contour.
|
|
vertices: Input array of vertices. Vertices for each contour
|
|
immediately follow those for previous one. Array location
|
|
vertices[0] must NOT be used (i.e. i/p starts from
|
|
vertices[1] instead. The output triangles are
|
|
specified w.r.t. the indices of these vertices.
|
|
|
|
triangles: Output array to hold triangles.
|
|
|
|
Enough space must be allocated for all the arrays before calling this routine
|
|
|
|
*/
|
|
|
|
|
|
extern "C" int is_point_inside_polygon(double * vertex);
|
|
/*
|
|
This function returns TRUE or FALSE depending upon whether the
|
|
vertex is inside the polygon or not. The polygon must already have
|
|
been triangulated before this routine is called.
|
|
This routine will always detect all the points belonging to the
|
|
set (polygon-area - polygon-boundary). The return value for points
|
|
on the boundary is not consistent!!!
|
|
|
|
*/
|
|
|
|
#define SEGSIZE_TRIANGULATION 10000
|
|
/*
|
|
max nr of segments.
|
|
Determines how many points can be specified as input.
|
|
If your datasets have large number of points,
|
|
increase this value (here and SEGSIZE in triangulat.h) accordingly.
|
|
|
|
*/
|
|
|
|
#endif
|