circutil.c File Reference

#include <math.h>

Include dependency graph for circutil.c:

Functions
int	pmCircleInit (PM_CIRCLE *circle, PM_CARTESIAN start, PM_CARTESIAN end, PM_CARTESIAN center, PM_CARTESIAN normal, int turn)
int	pmCirclePoint (PM_CIRCLE circle, double angle, PM_CARTESIAN point)

Function Documentation

int pmCircleInit	(	PM_CIRCLE *	circle,
		PM_CARTESIAN	start,
		PM_CARTESIAN	end,
		PM_CARTESIAN	center,
		PM_CARTESIAN	normal,
		int	turn
	)

Definition at line 20 of file circutil.c.

00024 {
00025   double dot;
00026   PM_CARTESIAN rEnd;
00027 
00028   if (0 == circle)
00029     {
00030       return -1;
00031     }
00032 
00033   /* load and normalize required descriptions */
00034   circle->start = start;
00035   circle->end = end;
00036   circle->center = center;
00037   pmCartNorm(normal, &circle->normal);
00038   circle->turn = turn;          /* 0 = 0..360, 1 = 360..720,
00039                                    -1 = 0..-360, -2 = -360..-720, etc. */
00040 
00041   /* radius */
00042   pmCartCartDisp(start, center, &circle->radius);
00043 
00044   /* vector in plane of circle from center to start, magnitude radius */
00045   pmCartCartSub(start, center, &circle->rTan);
00046 
00047   /* vector in plane of circle perpendicular to uTan, magnitude radius */
00048   pmCartCartCross(circle->normal, circle->rTan, &circle->rPerp);
00049 
00050   /* do rHelix, rEnd */
00051   pmCartCartSub(end, center, &circle->rHelix);
00052   pmCartPlaneProj(circle->rHelix, circle->normal, &rEnd);
00053   pmCartMag(rEnd, &circle->spiral);
00054   circle->spiral -= circle->radius;
00055   pmCartCartSub(circle->rHelix, rEnd, &circle->rHelix);
00056   pmCartNorm(rEnd, &rEnd);
00057   pmCartScalMult(rEnd, circle->radius, &rEnd);
00058 
00059   /* angle */
00060   pmCartCartDot(start, rEnd, &dot);
00061   dot = dot / (circle->radius * circle->radius);
00062   circle->angle = acos(dot);
00063   if (turn > 0)
00064     {
00065       circle->angle += turn * 2.0 * PM_PI;
00066     }
00067   else if (turn < 0)
00068     {
00069       circle->angle = - circle->angle - (turn + 1) * 2.0 * PM_PI;
00070     }
00071 
00072   return pmErrno = 0;
00073 }

int pmCirclePoint	(	PM_CIRCLE *	circle,
		double	angle,
		PM_CARTESIAN *	point
	)

Definition at line 80 of file circutil.c.

00081 {
00082   PM_CARTESIAN par, perp;
00083   double scale;
00084 
00085   /* compute components rel to center */
00086   pmCartScalMult(circle->rTan, cos(angle), &par);
00087   pmCartScalMult(circle->rPerp, sin(angle), &perp);
00088 
00089   /* add to get radius vector rel to center */
00090   pmCartCartAdd(par, perp, point);
00091 
00092   /* get scale for spiral, helix interpolation */
00093   scale = angle / circle->angle;
00094 
00095   /* add scaled vector in radial dir for spiral */
00096   pmCartNorm(*point, &par);
00097   pmCartScalMult(par, scale * circle->spiral, &par);
00098   pmCartCartAdd(*point, par, point);
00099 
00100   /* add scaled vector in helix dir */
00101   pmCartScalMult(circle->rHelix, scale, &perp);
00102   pmCartCartAdd(*point, perp, point);
00103 
00104   return pmErrno = 0;
00105 }

Generated on Sun Dec 2 15:56:58 2001 for rcslib by

circutil.c File Reference

Functions

Function Documentation