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/*
* MySeg.h
* nlivarot
*
* Created by fred on Wed Nov 12 2003.
*
*/
#ifndef my_math_seg
#define my_math_seg
#include "MyMath.h"
// codes for the intersections computations
// pt = point
// seg = segment
// dmd = half line
// dr = infinite line
enum
{
inters_seg_seg, // intersection between 2 segments
inters_seg_dmd, // intersection between one segment (parameter no 1) and one half-line (parameter no 2)
inters_seg_dr, // ....
inters_dmd_dmd,
inters_dmd_dr,
inters_dr_dr,
inters_seg_pt, // "intersection" between segment and point= "does the segment contain the point?"
inters_dmd_pt,
inters_dr_pt,
inters_orseg_pt // don't use
};
// return codes for the intersection computations; build as a concatenation of
// _a = first parameter
// _b = second parameter
// _st = start of the segment/half-line (lines don't have starts)
// _en = end of thz segment (half-lines and lines don't have ends)
// _mi = inside of the segment/half-line/line
// _colinear = this flag is set if the intersection of the 2 parameter is more than a point
// the first 2 bits of the return code contain the position of the intersection on the first parameter (_st, _mi or _en)
// the next 2 bits of the return code contain the position of the intersection on the second parameter (_st, _mi or _en)
// the 5th bit is set if the parameters are colinear
enum
{
inters_a_st = 1,
inters_a_mi = 2,
inters_a_en = 3,
inters_b_st = 4,
inters_b_mi = 8,
inters_b_en = 12,
inters_colinear = 16
};
//
// a class to describe a segment: defined by its startpoint p and its direction d
// if the object is considered as a segment: p+xd, where x ranges from 0 to 1
// if the object is considered as an half-line, the length of the direction vector doesn't matter:
// p+xd, where x ranges from 0 to +infinity
// if the object is considered as a line: p+xd, where x ranges from -infinity to +infinity
//
class L_SEG
{
public:
vec2d p, d;
// constructors
L_SEG (vec2d & st, vec2d & dir):p (st), d (dir)
{
}; // by default, you give one startpoint and one direction
L_SEG (void)
{
};
~L_SEG (void)
{
};
// assignations
void Set (L_SEG * s)
{
p = s->p;
d = s->d;
};
void Set (L_SEG & s)
{
p = s.p;
d = s.d;
};
// 2 specific assignations:
// assignation where you give the startpoint and the direction (like in the constructor):
void SetSD (vec2d & st, vec2d & dir)
{
p = st;
d = dir;
};
// assignation where you give the startpoint and the endpoint:
void SetSE (vec2d & st, vec2d & en)
{
p = st;
d.x = en.x - st.x;
d.y = en.y - st.y;
};
// reverses the segment
void Rev (void)
{
p.x += d.x;
p.y += d.y;
d.x = -d.x;
d.y = -d.y;
};
// transitibve version: the reversed segment is stored in s
void Rev (L_SEG & s)
{
s.p.x = p.x + d.x;
s.p.y = p.y + d.y;
s.d.x = -d.x;
s.d.y = -d.y;
};
// distance of the point iv to the segment/half-line/line
// the mode parameter specifies how the caller instance should be handled:
// inters_seg_pt : segment
// inters_dmd_pt : half-line
// inters_dr_pt : line
void Distance (vec2d & iv, double &d, int mode = inters_dr_pt);
// distance between 2 segments
// mode parameter specifies how the segments have to be treated (just like above)
void Distance (L_SEG & is, double &d, int mode = inters_seg_seg);
// tests if the segment contains the point pos
// mode is as in the Distance function
int Contains (vec2d & pos, int mode);
// intersection between 2 lines/half-lines/segments
// mode specifies how the L_SEG instances have to be considered; codes at the beginning of this file
// the "at" parameter stores the intersection point, if it exists and is unique
static int Intersect (L_SEG & iu, L_SEG & iv, int mode);
static int Intersect (L_SEG & iu, L_SEG & iv, vec2d & at, int mode);
// specific version, when you can garantuee the colinearity case won't occur
static int IntersectGeneral (L_SEG & iu, L_SEG & iv, vec2d & at, int mode);
};
#endif
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