hello world

neo/idlib/math/Pluecker.cpp

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+/*
+===========================================================================
+
+Doom 3 GPL Source Code
+Copyright (C) 1999-2011 id Software LLC, a ZeniMax Media company. 
+
+This file is part of the Doom 3 GPL Source Code (?Doom 3 Source Code?).  
+
+Doom 3 Source Code is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+Doom 3 Source Code is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with Doom 3 Source Code.  If not, see <http://www.gnu.org/licenses/>.
+
+In addition, the Doom 3 Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 Source Code.  If not, please request a copy in writing from id Software at the address below.
+
+If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.
+
+===========================================================================
+*/
+
+#include "../precompiled.h"
+#pragma hdrstop
+
+idPluecker pluecker_origin( 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f );
+
+/*
+================
+idPluecker::FromPlanes
+
+  pluecker coordinate for the intersection of two planes
+================
+*/
+bool idPluecker::FromPlanes( const idPlane &p1, const idPlane &p2 ) {
+
+	p[0] = -( p1[2] * -p2[3] - p2[2] * -p1[3] );
+	p[1] = -( p2[1] * -p1[3] - p1[1] * -p2[3] );
+	p[2] = p1[1] * p2[2] - p2[1] * p1[2];
+
+	p[3] = -( p1[0] * -p2[3] - p2[0] * -p1[3] );
+	p[4] = p1[0] * p2[1] - p2[0] * p1[1];
+	p[5] = p1[0] * p2[2] - p2[0] * p1[2];
+
+	return ( p[2] != 0.0f || p[5] != 0.0f || p[4] != 0.0f );
+}
+
+/*
+================
+idPluecker::Distance3DSqr
+
+  calculates square of shortest distance between the two
+  3D lines represented by their pluecker coordinates
+================
+*/
+float idPluecker::Distance3DSqr( const idPluecker &a ) const {
+	float d, s;
+	idVec3 dir;
+
+	dir[0] = -a.p[5] *  p[4] -  a.p[4] * -p[5];
+	dir[1] =  a.p[4] *  p[2] -  a.p[2] *  p[4];
+	dir[2] =  a.p[2] * -p[5] - -a.p[5] *  p[2];
+	if ( dir[0] == 0.0f && dir[1] == 0.0f && dir[2] == 0.0f ) {
+		return -1.0f;	// FIXME: implement for parallel lines
+	}
+	d = a.p[4] * ( p[2]*dir[1] - -p[5]*dir[0]) +
+		a.p[5] * ( p[2]*dir[2] -  p[4]*dir[0]) +
+		a.p[2] * (-p[5]*dir[2] -  p[4]*dir[1]);
+	s = PermutedInnerProduct( a ) / d;
+	return ( dir * dir ) * ( s * s );
+}
+
+/*
+=============
+idPluecker::ToString
+=============
+*/
+const char *idPluecker::ToString( int precision ) const {
+	return idStr::FloatArrayToString( ToFloatPtr(), GetDimension(), precision );
+}