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[Positioning] Point3D: fix angle() 

Use doubles instead of floats.
Handle the cases where points are equal.
This commit is contained in:
Matteo Cypriani 2011-07-18 13:35:02 +02:00
parent 33b027d472
commit f5a4f4fedc
1 changed files with 11 additions and 4 deletions
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15
owlps-positioning/src/point3d.cc
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@ -64,17 +64,24 @@ float Point3D::square_distance(const float _x,
/**
* A, B and C are three points, A being the current Point3D (*this).
* @return The angle BÂC.
* If the points are aligned, the angle returned is always 0° (and not
* 180°, even in the case where A is on BC).
* @returns The angle BÂC, in the interval [0, 180] degrees.
*/
double Point3D::angle(const Point3D &b, const Point3D &c) const
{
float
double
sq_ab = square_distance(b),
ab = sqrt(sq_ab),
sq_ac = square_distance(c),
ac = sqrt(sq_ac),
sq_bc = b.square_distance(c) ;
if (sq_ab == 0 || sq_ac == 0 || sq_bc == 0)
return 0 ;
double
ab = sqrt(sq_ab),
ac = sqrt(sq_ac) ;
double cos_bac = (sq_ab + sq_ac - sq_bc) / (2 * ab * ac) ;
double bac = acos(cos_bac) ;