pldist.c File Reference

Calculate distance from a point to a line. More...

#include <stdio.h>
#include <math.h>
#include "MathType.h"

Go to the source code of this file.

Macros
#define	CROSSPRODUCT(p1, p2, p3)
#define	DOTPRODUCT(v1, v2)   ((v1).x*(v2).x + (v1).y*(v2).y + (v1).z*(v2).z)

Functions
REAL	blPointLineDistance (REAL Px, REAL Py, REAL Pz, REAL P1x, REAL P1y, REAL P1z, REAL P2x, REAL P2y, REAL P2z, REAL *Rx, REAL *Ry, REAL *Rz, REAL *frac)

Detailed Description

Calculate distance from a point to a line.

Version

V1.1

Date

07.07.14

Copyright

(c) University of Reading / Dr. Andrew C. R. Martin 1999-2014

Author

Dr. Andrew C. R. Martin

Institute of Structural & Molecular Biology, University College London, Gower Street, London. WC1E 6BT.

andre.nosp@m.w@bi.nosp@m.oinf..nosp@m.org..nosp@m.uk andre.nosp@m.w.ma.nosp@m.rtin@.nosp@m.ucl..nosp@m.ac.uk

This code is NOT IN THE PUBLIC DOMAIN, but it may be copied according to the conditions laid out in the accompanying file COPYING.DOC.

The code may be modified as required, but any modifications must be documented so that the person responsible can be identified.

The code may not be sold commercially or included as part of a commercial product except as described in the file COPYING.DOC.

Description:

Usage:

Revision History:

• V1.1 07.07.14 Use bl prefix for functions By: CTP

Definition in file pldist.c.

Macro Definition Documentation

#define CROSSPRODUCT	(		p1,
			p2,
			p3
	)

Value:

(p3).x = (p1).y*(p2).z - (p1).z*(p2).y; \
        (p3).y = (p1).z*(p2).x - (p1).x*(p2).z; \
        (p3).z = (p1).x*(p2).y - (p1).y*(p2).x

Definition at line 73 of file pldist.c.

#define DOTPRODUCT	(		v1,
			v2
	)		((v1).x*(v2).x + (v1).y*(v2).y + (v1).z*(v2).z)

Definition at line 77 of file pldist.c.

Function Documentation

REAL blPointLineDistance	(	REAL	Px,
		REAL	Py,
		REAL	Pz,
		REAL	P1x,
		REAL	P1y,
		REAL	P1z,
		REAL	P2x,
		REAL	P2y,
		REAL	P2z,
		REAL *	Rx,
		REAL *	Ry,
		REAL *	Rz,
		REAL *	frac
	)

Parameters

[in]	Px	Point x coordinate
[in]	Py	Point y coordinate
[in]	Pz	Point z coordinate
[in]	P1x	Line start x coordinate
[in]	P1y	Line start y coordinate
[in]	P1z	Line start z coordinate
[in]	P2x	Line end x coordinate
[in]	P2y	Line end y coordinate
[in]	P2z	Line end z coordinate
[out]	*Rx	Nearest point on line x coordinate
[out]	*Ry	Nearest point on line y coordinate
[out]	*Rz	Nearest point on line z coordinate
[out]	*frac	Fraction along P1-P2 of R

Returns

Distance from P to R

Calculates the shortest distance from a point P to a line between points P1 and P2. This value is returned.

If the Rx,Ry,Rz pointers are all non-NULL, then the point on the line nearest to P is output.

If the frac pointer is non-NULL then the fraction of R along the P1-P2 vector is output. Thus: R==P1 ==> frac=0 R==P2 ==> frac=1 Thus if (0<=frac<=1) then the point R is within the line segment P1-P2

• 16.11.99 Original By: ACRM
• 07.07.14 Use bl prefix for functions By: CTP

Definition at line 126 of file pldist.c.