From 7a817031e7e1c52c51297f679a02b7b105ffc97d Mon Sep 17 00:00:00 2001
From: Jean-Francois Remacle <jean-francois.remacle@uclouvain.be>
Date: Wed, 14 Mar 2007 10:21:12 +0000
Subject: [PATCH] *** empty log message ***
---
Geo/gmshSurface.cpp | 22 +++++++---------------
1 file changed, 7 insertions(+), 15 deletions(-)
diff --git a/Geo/gmshSurface.cpp b/Geo/gmshSurface.cpp
index 55e7bbf147..09abb0d92f 100644
--- a/Geo/gmshSurface.cpp
+++ b/Geo/gmshSurface.cpp
@@ -1,4 +1,4 @@
-// $Id: gmshSurface.cpp,v 1.7 2007-03-02 14:36:38 geuzaine Exp $
+// $Id: gmshSurface.cpp,v 1.8 2007-03-14 10:21:12 remacle Exp $
//
// Copyright (C) 1997-2007 C. Geuzaine, J.-F. Remacle
//
@@ -70,22 +70,14 @@ gmshSurface * gmshPolarSphere::NewPolarSphere(int iSphere, double x, double y, d
allGmshSurfaces[iSphere] = sph;
return sph;
}
-
SPoint3 gmshPolarSphere::point (double parA, double parB) const
{
- /*double ra,phi;
- ra=hypot(parA,parB);
- phi=2*atan((parB/ra)/(1+parA/ra));
- double par1=-phi;
- double par2=M_PI-ra;
-
- //par2 += M_PI*.5;
- const double x = xc + r * sin(par2) * cos(par1);
- const double y = yc + r * sin(par2) * sin(par1);
- const double z = zc - r * cos(par2);
- // printf("%g %g - %g %g %g\n",par1,par2,x,y,z);*/
- double f=2*r/(parA*parA+parB*parB+4*r*r);
- return SPoint3(f*2*parA*r, f*2*parB*r, f*(parA*parA+parB*parB));
+ //stereographic projection from the south pole, origin of the axis at the center of the sphere
+ //parA=2rx/(r+z)
+ //parB=2ry/(r+z)
+ double rp2=parA*parA+parB*parB;
+ double z=r*(4*r*r-rp2)/(4*r*r+rp2);
+ return SPoint3((r+z)*parA/(2*r),(r+z)*parB/(2*r),z);
}
--
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