blender-archive/source/blender/blenlib/BLI_convexhull_2d.h

/* SPDX-License-Identifier: GPL-2.0-or-later */

#pragma once

/** \file
 * \ingroup bli
 */

#ifdef __cplusplus
extern "C" {
#endif

/**
 * A.M. Andrew's monotone chain 2D convex hull algorithm.
 *
 * \param points: An array of 2D points presorted by increasing x and y-coords.
 * \param n: The number of points in points.
 * \param r_points: An array of the convex hull vertex indices (max is n).
 * \returns the number of points in r_points.
 */
int BLI_convexhull_2d_sorted(const float (*points)[2], int n, int r_points[]);
/**
 * A.M. Andrew's monotone chain 2D convex hull algorithm.
 *
 * \param points: An array of 2D points.
 * \param n: The number of points in points.
 * \param r_points: An array of the convex hull vertex indices (max is n).
 * _must_ be allocated as `n * 2` because of how its used internally,
 * even though the final result will be no more than \a n in size.
 * \returns the number of points in r_points.
 */
int BLI_convexhull_2d(const float (*points)[2], int n, int r_points[]);

/**
 * \return The best angle for fitting the convex hull to an axis aligned bounding box.
 *
 * Intended to be used with #BLI_convexhull_2d
 *
 * \param points_hull: Ordered hull points
 * (result of #BLI_convexhull_2d mapped to a contiguous array).
 *
 * \note we could return the index of the best edge too if its needed.
 */
float BLI_convexhull_aabb_fit_hull_2d(const float (*points_hull)[2], unsigned int n);
/**
 * Wrap #BLI_convexhull_aabb_fit_hull_2d and do the convex hull calculation.
 *
 * \param points: arbitrary 2d points.
 */
float BLI_convexhull_aabb_fit_points_2d(const float (*points)[2], unsigned int n);

#ifdef __cplusplus
}
#endif