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