YetAnotherCoupler: src/core/intersection.c File Reference

#include <stdlib.h>
#include <math.h>
#include <stdio.h>
#include "utils_core.h"
#include "geometry.h"

Include dependency graph for intersection.c:

Enumerations
enum	{ p_on_a = 1 , q_on_a = 2 , p_on_b = 4 , q_on_b = 8 , circles_are_identical = 16 }

enum	{ no_intersection = 0 , a_between_cd = 1 , b_between_cd = 2 , c_between_ab = 4 , d_between_ab = 8 }

Functions
static int	gcxgc (double const norm_vector_a[3], double const norm_vector_b[3], double p[3], double q[3])

static int	loncxlatc (double const gc_norm_vector[3], double const z, double p[3], double q[3])

static int	gcxlatc (double const gc_norm_vector[3], double const z, double p[3], double q[3])

static int	loncxlonc (double const norm_vector_a[3], double const norm_vector_b[3], double p[3], double q[3])

static int	pxgc (double const vec[3], double const norm_vector[3], double p[3], double q[3])

static int	pxlatc (double const vec[3], double z, double p[3], double q[3])

static int	pxp (double const vec_a[3], double const vec_b[3], double p[3], double q[3])

int	yac_circle_intersect (struct yac_circle a, struct yac_circle b, double p[3], double q[3])

static int	vector_is_between (double const a[], double const b[], double const p[], double sq_len_diff_ab)

static int	vector_is_between_lat (double const a[], double const b[], double const p[])

static void	compute_edge_middle_point_vec (enum yac_edge_type edge_type, double const a[3], double const b[3], double middle[3])

static int	yac_identical_circles_vec (enum yac_edge_type edge_type, double const a[3], double const b[3], double const c[3], double const d[3], double p[3], double q[3], int intersection_type)

static int	yac_identical_gcxgc_vec (double const a[3], double const b[3], double const c[3], double const d[3], double p[3], double q[3])

static int	yac_check_pq_gcxgc (double const a[3], double const b[3], double const c[3], double const d[3], double const p[3], double const q[3])

static void	compute_norm_vector (double const a[3], double const b[3], double norm_vector[3])

static int	yac_gcxgc_vec (double const a[3], double const b[3], double const c[3], double const d[3], double p[3], double q[3])

static int	yac_latcxlatc_vec (double const a[3], double const b[3], double const c[3], double const d[3], double p[3], double q[3])
	compute the intersection point two circles of latitude

static void	compute_lon_norm_vector (double const a[3], double const b[3], double norm_vector[3])

static int	yac_loncxlonc_vec (double const a[3], double const b[3], double const c[3], double const d[3], double p[3], double q[3])
	compute the intersection point two circles of longitude

static int	yac_check_pq_gcxlatc (double const a[3], double const b[3], double const c[3], double const d[3], double const p[3], double const q[3])

static int	yac_loncxlatc_vec (double const a[3], double const b[3], double const c[3], double const d[3], double p[3], double q[3])
	compute the intersection point of a meridian and a parallel

static int	yac_gcxlatc_vec (double const a[3], double const b[3], double const c[3], double const d[3], double p[3], double q[3])
	compute the intersection of a great circle with the parallel

static int	yac_pxp_vec (double const a[3], double const b[3], double p[3], double q[3])

static int	yac_pxgc_vec (double const point[3], double const a[3], double const b[3], double p[3], double q[3])

static int	yac_pxlat_vec (double const point[3], double const a[3], double const b[3], double p[3], double q[3])

static int	adjust_ret_value (int ret_value)

int	yac_intersect_vec (enum yac_edge_type edge_type_a, double const a[3], double const b[3], enum yac_edge_type edge_type_b, double const c[3], double const d[3], double p[3], double q[3])

int	yac_point_on_edge (double p[3], double const a[3], double const b[3], enum yac_circle_type circle_type)

Variables
static double const	tol = 1.0e-12

Enumeration Type Documentation

◆ anonymous enum

anonymous enum

Enumerator
p_on_a
q_on_a
p_on_b
q_on_b
circles_are_identical

Definition at line 15 of file intersection.c.

◆ anonymous enum

anonymous enum

Enumerator
no_intersection
a_between_cd
b_between_cd
c_between_ab
d_between_ab

Definition at line 23 of file intersection.c.

Function Documentation

◆ adjust_ret_value()

static int adjust_ret_value ( int ret_value )

inlinestatic

Definition at line 780 of file intersection.c.

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◆ compute_edge_middle_point_vec()

static void compute_edge_middle_point_vec	(	enum yac_edge_type	edge_type,
		double const	a[3],
		double const	b[3],
		double	middle[3]
	)

static

Definition at line 374 of file intersection.c.

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◆ compute_lon_norm_vector()

static void compute_lon_norm_vector	(	double const	a[3],
		double const	b[3],
		double	norm_vector[3]
	)

static

Definition at line 586 of file intersection.c.

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◆ compute_norm_vector()

static void compute_norm_vector	(	double const	a[3],
		double const	b[3],
		double	norm_vector[3]
	)

static

Definition at line 499 of file intersection.c.

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◆ gcxgc()

static int gcxgc	(	double const	norm_vector_a[3],
		double const	norm_vector_b[3],
		double	p[3],
		double	q[3]
	)

static

computes the intersection of two great circles

Parameters

[in]	norm_vector_a	norm vector of circle a
[in]	norm_vector_b	norm vector of circle b
[out]	p	first intersection point
[out]	q	second intersection point

Returns: -1 if the two circles are identical; 2 otherwise

Definition at line 39 of file intersection.c.

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◆ gcxlatc()

static int gcxlatc	(	double const	gc_norm_vector[3],
		double const	z,
		double	p[3],
		double	q[3]
	)

static

Definition at line 94 of file intersection.c.

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◆ loncxlatc()

static int loncxlatc	(	double const	gc_norm_vector[3],
		double const	z,
		double	p[3],
		double	q[3]
	)

static

Definition at line 71 of file intersection.c.

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◆ loncxlonc()

static int loncxlonc	(	double const	norm_vector_a[3],
		double const	norm_vector_b[3],
		double	p[3],
		double	q[3]
	)

static

Definition at line 194 of file intersection.c.

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◆ pxgc()

static int pxgc	(	double const	vec[3],
		double const	norm_vector[3],
		double	p[3],
		double	q[3]
	)

static

Definition at line 222 of file intersection.c.

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◆ pxlatc()

static int pxlatc	(	double const	vec[3],
		double	z,
		double	p[3],
		double	q[3]
	)

static

Definition at line 244 of file intersection.c.

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◆ pxp()

static int pxp	(	double const	vec_a[3],
		double const	vec_b[3],
		double	p[3],
		double	q[3]
	)

static

Definition at line 256 of file intersection.c.

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◆ vector_is_between()

static int vector_is_between	(	double const	a[],
		double const	b[],
		double const	p[],
		double	sq_len_diff_ab
	)

inlinestatic

determines whether vector p is between vectors a and b (it is assumed, that a, b, and p are in the same plane)

Definition at line 319 of file intersection.c.

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◆ vector_is_between_lat()

static int vector_is_between_lat	(	double const	a[],
		double const	b[],
		double const	p[]
	)

static

Definition at line 336 of file intersection.c.

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◆ yac_check_pq_gcxgc()

static int yac_check_pq_gcxgc	(	double const	a[3],
		double const	b[3],
		double const	c[3],
		double const	d[3],
		double const	p[3],
		double const	q[3]
	)

static

Definition at line 485 of file intersection.c.

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◆ yac_check_pq_gcxlatc()

static int yac_check_pq_gcxlatc	(	double const	a[3],
		double const	b[3],
		double const	c[3],
		double const	d[3],
		double const	p[3],
		double const	q[3]
	)

static

Definition at line 635 of file intersection.c.

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◆ yac_circle_intersect()

int yac_circle_intersect	(	struct yac_circle	a,
		struct yac_circle	b,
		double	p[3],
		double	q[3]
	)

Definition at line 270 of file intersection.c.

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◆ yac_gcxgc_vec()

static int yac_gcxgc_vec	(	double const	a[3],
		double const	b[3],
		double const	c[3],
		double const	d[3],
		double	p[3],
		double	q[3]
	)

static

computes the intersection points of two great circles
based on http://www.geoclub.de/viewtopic.php?f=54&t=29689

Parameters

[in]	a	first point of edge a the is on a great circle
[in]	b	second point of edge a the is on a great circle
[in]	c	first point of edge b the is on a great circle
[in]	d	second point of edge b the is on a great circle
[out]	p	intersection point
[out]	q	intersection point

Returns: 0 if the intersection points are neither on edge a or b
-1 if an error occurred
1st bit will be set if p is on edge a
2nd bit will be set if q is on edge a
3rd bit will be set if p is on edge b
4th bit will be set if q is on edge b 5th bit will be set if both great circles are identically

Remarks: both edges need to have length of at least yac_angle_tol

Definition at line 535 of file intersection.c.

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◆ yac_gcxlatc_vec()

static int yac_gcxlatc_vec	(	double const	a[3],
		double const	b[3],
		double const	c[3],
		double const	d[3],
		double	p[3],
		double	q[3]
	)

static

compute the intersection of a great circle with the parallel

compute the intersection points of a great circle (defined by a and b) and a circle of latitude (defined by c and d) (both circles need to have a length of at least yac_angle_tol) if p and q are != NULL they contain the intersection points the return value is:

0 if the intersection points are neither between (a and b) or (c and d)
-1 if the two circles do not intersect or an error occurred
1st bit will be set if p is between a and b
2nd bit will be set if q is between a and b
3rd bit will be set if p is between c and d
4th bit will be set if q is between c and d
5th bit will be set if both circles are identically
Remarks
if -1 is returned neither p or q is set

if the two circles only have one intersection point, p and q will be identically, but only the p bits will be set

both edges need to have length of at least yac_angle_tol

Definition at line 708 of file intersection.c.

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◆ yac_identical_circles_vec()

static int yac_identical_circles_vec	(	enum yac_edge_type	edge_type,
		double const	a[3],
		double const	b[3],
		double const	c[3],
		double const	d[3],
		double	p[3],
		double	q[3],
		int	intersection_type
	)

static

Definition at line 396 of file intersection.c.

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◆ yac_identical_gcxgc_vec()

static int yac_identical_gcxgc_vec	(	double const	a[3],
		double const	b[3],
		double const	c[3],
		double const	d[3],
		double	p[3],
		double	q[3]
	)

static

Definition at line 468 of file intersection.c.

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◆ yac_intersect_vec()

int yac_intersect_vec	(	enum yac_edge_type	edge_type_a,
		double const	a[3],
		double const	b[3],
		enum yac_edge_type	edge_type_b,
		double const	c[3],
		double const	d[3],
		double	p[3],
		double	q[3]
	)

computes the intersection points of two edges

Parameters

[in]	edge_type_a	type of edge a
[in]	a	first point of edge a
[in]	b	second point of edge a
[in]	edge_type_b	type of edge b
[in]	c	first point of edge b
[in]	d	second point of edge b
[out]	p	first intersection point
[out]	q	second intersection point

Returns: 0 if the intersection points are neither on edge a or b
-1 if the two circles do not intersect
1st bit will be set if p is on edge a
2nd bit will be set if q is on edge a
3rd bit will be set if p is on edge b
4th bit will be set if q is on edge b
5th bit will be set if both circles are identically

Remarks: if -1 is returned neither p or q is set; if the two circles only have one intersection point, p and q will be identically, but only the p bits will be set

Definition at line 786 of file intersection.c.

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◆ yac_latcxlatc_vec()

static int yac_latcxlatc_vec	(	double const	a[3],
		double const	b[3],
		double const	c[3],
		double const	d[3],
		double	p[3],
		double	q[3]
	)

static

compute the intersection point two circles of latitude

compute the intersection points of two circle of latitude if p and q are != NULL they contain the intersection points the return value is:

0 if the intersection points are neither between (a and b) or (c and d)
-1 if an error occurred
1st bit will be set if p is between a and b
2nd bit will be set if q is between a and b
3rd bit will be set if p is between c and d
4th bit will be set if q is between c and d
5th bit will be set if both edges are on the same circle of latitude
Remarks
both edges need to have length of at least yac_angle_tol

Definition at line 570 of file intersection.c.

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◆ yac_loncxlatc_vec()

static int yac_loncxlatc_vec	(	double const	a[3],
		double const	b[3],
		double const	c[3],
		double const	d[3],
		double	p[3],
		double	q[3]
	)

static

compute the intersection point of a meridian and a parallel

compute the intersection points of a circle of longitude (defined by a and b) and a circle of latitude (defined by c and d) if p and q are != NULL they contain the intersection points the return value is:

0 if the intersection points are neither between (a and b) or (c and d)
-1 if an error occurred
1st bit will be set if p is between a and b
2nd bit will be set if q is between a and b
3rd bit will be set if p is between c and d
4th bit will be set if q is between c and d
Remarks
both edges need to have length of at least yac_angle_tol

Definition at line 666 of file intersection.c.

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◆ yac_loncxlonc_vec()

static int yac_loncxlonc_vec	(	double const	a[3],
		double const	b[3],
		double const	c[3],
		double const	d[3],
		double	p[3],
		double	q[3]
	)

static

compute the intersection point two circles of longitude

compute the intersection points of two circle of longitude if p and q are != NULL they contain the intersection points the return value is:

0 if the intersection points are neither between (a and b) or (c and d)
-1 if an error occurred
1st bit will be set if p is between a and b
2nd bit will be set if q is between a and b
3rd bit will be set if p is between c and d
4th bit will be set if q is between c and d
5th bit will be set if both edges are on the same circle of longitude
Remarks
both edges need to have length of at least yac_angle_tol

Definition at line 616 of file intersection.c.

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◆ yac_point_on_edge()

int yac_point_on_edge	(	double	p[3],
		double const	a[3],
		double const	b[3],
		enum yac_circle_type	circle_type
	)

Definition at line 883 of file intersection.c.

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◆ yac_pxgc_vec()

static int yac_pxgc_vec	(	double const	point[3],
		double const	a[3],
		double const	b[3],
		double	p[3],
		double	q[3]
	)

static

Definition at line 739 of file intersection.c.

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◆ yac_pxlat_vec()

static int yac_pxlat_vec	(	double const	point[3],
		double const	a[3],
		double const	b[3],
		double	p[3],
		double	q[3]
	)

static

Definition at line 763 of file intersection.c.

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◆ yac_pxp_vec()

static int yac_pxp_vec	(	double const	a[3],
		double const	b[3],
		double	p[3],
		double	q[3]
	)

static

Definition at line 733 of file intersection.c.

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Variable Documentation

◆ tol

double const tol = 1.0e-12

static

Definition at line 13 of file intersection.c.

Enumerations

Functions

Variables

Enumeration Type Documentation

◆ anonymous enum

◆ anonymous enum

Function Documentation

◆ adjust_ret_value()

◆ compute_edge_middle_point_vec()

◆ compute_lon_norm_vector()

◆ compute_norm_vector()

◆ gcxgc()

◆ gcxlatc()

◆ loncxlatc()

◆ loncxlonc()

◆ pxgc()

◆ pxlatc()

◆ pxp()

◆ vector_is_between()

◆ vector_is_between_lat()

◆ yac_check_pq_gcxgc()

◆ yac_check_pq_gcxlatc()

◆ yac_circle_intersect()

◆ yac_gcxgc_vec()

◆ yac_gcxlatc_vec()

◆ yac_identical_circles_vec()

◆ yac_identical_gcxgc_vec()

◆ yac_intersect_vec()

◆ yac_latcxlatc_vec()

◆ yac_loncxlatc_vec()

◆ yac_loncxlonc_vec()

◆ yac_point_on_edge()

◆ yac_pxgc_vec()

◆ yac_pxlat_vec()

◆ yac_pxp_vec()

Variable Documentation

◆ tol