add localFrame compression support

include/Utils/localFrame.h

+/*******************************************************************************
+* CGoGN: Combinatorial and Geometric modeling with Generic N-dimensional Maps  *
+* version 0.1                                                                  *
+* Copyright (C) 2009-2011, IGG Team, LSIIT, University of Strasbourg           *
+*                                                                              *
+* This library is free software; you can redistribute it and/or modify it      *
+* under the terms of the GNU Lesser General Public License as published by the *
+* Free Software Foundation; either version 2.1 of the License, or (at your     *
+* option) any later version.                                                   *
+*                                                                              *
+* This library 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 Lesser General Public License  *
+* for more details.                                                            *
+*                                                                              *
+* You should have received a copy of the GNU Lesser General Public License     *
+* along with this library; if not, write to the Free Software Foundation,      *
+* Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA.           *
+*                                                                              *
+* Web site: http://cgogn.u-strasbg.fr/                                         *
+* Contact information: cgogn@unistra.fr                                        *
+*                                                                              *
+*******************************************************************************/
+
+#ifndef LOCALFRAME_H_
+#define LOCALFRAME_H_
+
+namespace CGoGN {
+
+namespace Utils {
+
+/**
+ * Class for representing a direct local frame composed of 3 orthonormal vectors T (tangent), B (bitangent) and N (normal).
+ * This class can compress/decompress a local frame, switching from its explicit representation (3 vectors) to its compressed representation (1 vector).
+ * Usage :
+ *  VEC3 T,B,N ;							// current set of orthonormal vectors composing the direct frame.
+ *  LocalFrame<PFP::VEC3> lf(T,B,N) ; 				// Constructor from explicit expression.
+ *  if (lf.isOrthoNormalDirect())			// test if the frame is Orthogonal, Normalized and Direct
+ *   VEC3 compressed = lf.getCompressed() ;	// Extract compressed frame
+ *  LocalFrame<PFP::VEC3> decompressed(compressed) ;	// Constructor from implicit (compressed) expression.
+ *
+ * All formulae were provided by "Représentation compacte d'un repère local", june 14th, 2011 by K. Vanhoey
+ */
+template <typename PFP>
+class LocalFrame
+{
+	typedef typename PFP::REAL REAL ;
+	typedef typename PFP::VEC2 VEC2 ;
+	typedef typename PFP::VEC3 VEC3 ;
+
+private: // fields
+	/**
+	 * The three explicit vectors
+	 */
+	VEC3 m_T,m_B,m_N ;
+
+public: // methods
+	/**
+	 * Constructor from explicit data
+	 * @param T the tangent vector
+	 * @param B the bitangent vector
+	 * @param N the normal vector
+	 */
+	LocalFrame(const VEC3& T, const VEC3& B, const VEC3& N) ;
+	/**
+	 * Constructor from implicit (compressed representation)
+	 * @param compressedFrame an implicit (compressed) version of the local frame
+	 */
+	LocalFrame(const VEC3& compressedFrame) ;
+	~LocalFrame() {} ;
+
+	/**
+	 * Returns a compressed version of the current local frame
+	 */
+	VEC3 getCompressed() ;
+
+	/**
+	 * Tests if the frame is direct
+	 * @return true if the frame is direct
+	 */
+	bool isDirect() ;
+
+	/**
+	 * Tests if the frame is orthogonal
+	 * @return true if the frame is orthogonal
+	 */
+	bool isOrthogonal() ;
+
+	/**
+	 * Tests if the frame is normalized
+	 * @return true if the frame is normalized
+	 */
+	bool isNormalized() ;
+
+	/**
+	 * Tests if the frame is direct, normalized and orthogonal
+	 * @return true if the frame is direct, normalized and orthogonal
+	 */
+	bool isOrthoNormalDirect() ;
+
+	/**
+	 * @return current tangent vector
+	 */
+	VEC3& getT() { return m_T ; }
+	const VEC3& getT() const { return m_T ; }
+
+	/**
+	 * @return current bitangent vector
+	 */
+	VEC3& getB() { return m_B ; }
+	const VEC3& getB() const { return m_B ; }
+
+	/**
+	 * @return current normal vector
+	 */
+	VEC3& getN() { return m_N ; }
+	const VEC3& getN() const { return m_N ; }
+
+	friend std::ostream& operator<< (std::ostream &out, const LocalFrame& lf) {
+		out << "T : " << lf.m_T << std::endl ;
+		out << "B : " << lf.m_B << std::endl ;
+		out << "N : " << lf.m_N << std::endl ;
+		return out ;
+	} ;
+
+private : // methods
+	VEC2 carthToSpherical(const VEC3& carth) const ;
+	VEC3 sphericalToCarth(const VEC2& sph) const ;
+} ;
+
+} // Utils
+
+} // CGoGN
+
+#include "localFrame.hpp"
+
+#endif /* LOCALFRAME_H_ */

include/Utils/localFrame.hpp

+/*******************************************************************************
+* CGoGN: Combinatorial and Geometric modeling with Generic N-dimensional Maps  *
+* version 0.1                                                                  *
+* Copyright (C) 2009-2011, IGG Team, LSIIT, University of Strasbourg           *
+*                                                                              *
+* This library is free software; you can redistribute it and/or modify it      *
+* under the terms of the GNU Lesser General Public License as published by the *
+* Free Software Foundation; either version 2.1 of the License, or (at your     *
+* option) any later version.                                                   *
+*                                                                              *
+* This library 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 Lesser General Public License  *
+* for more details.                                                            *
+*                                                                              *
+* You should have received a copy of the GNU Lesser General Public License     *
+* along with this library; if not, write to the Free Software Foundation,      *
+* Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA.           *
+*                                                                              *
+* Web site: http://cgogn.u-strasbg.fr/                                         *
+* Contact information: cgogn@unistra.fr                                        *
+*                                                                              *
+*******************************************************************************/
+
+namespace CGoGN {
+
+
+namespace Utils {
+
+template<typename PFP>
+LocalFrame<PFP>::LocalFrame(const VEC3& T, const VEC3& B, const VEC3& N)
+{
+	m_T = T ;
+	m_B = B ;
+	m_N = N ;
+}
+
+template<typename PFP>
+LocalFrame<PFP>::LocalFrame(const VEC3& compressedFrame)
+{
+	VEC2 Nspher ;
+	VEC2 Tspher ;
+
+	REAL& thetaN = Nspher[0] ; // known
+	REAL& phiN = Nspher[1] ; // known
+	REAL& thetaT = Tspher[0] ; // known
+	REAL& phiT = Tspher[1] ; // to be decoded
+
+	// compute phiT
+	REAL Den,Nom ;
+	Den = sin(phiN)*(cos(thetaN)*cos(thetaT) + sin(thetaN)*sin(thetaT)) ; // Based on orthogonality
+	Nom = cos(phiN) ;
+	phiT = -atan(Nom/Den) ; // if A==0, atan returns Pi/2
+	if (phiT < 0.0)
+		phiT = M_PI + phiT ; // = Pi - |phiT|
+
+	// convert to carthesian
+	m_N = sphericalToCarth(Nspher) ;
+	m_T = sphericalToCarth(Tspher) ;
+
+	// compute B
+	m_B = m_N ^ m_T ;
+}
+
+template<typename PFP>
+typename PFP::VEC3 LocalFrame<PFP>::getCompressed()
+{
+	VEC3 res ;
+
+	REAL& thetaN = res[0] ;
+	REAL& phiN = res[1] ;
+	REAL& thetaT = res[2] ;
+
+	// convert to spherical coordinates
+	VEC2 Nspher = carthToSpherical(m_N) ;
+	VEC2 Tspher = carthToSpherical(m_T) ;
+
+	// extract the three scalars
+	thetaN = Nspher[0] ;
+	phiN = Nspher[1] ;
+	thetaT = Tspher[0] ;
+
+	return res ;
+}
+
+template<typename PFP>
+bool LocalFrame<PFP>::isDirect()
+{
+	VEC3 new_B = m_N ^ m_T ;		// direct
+	VEC3 diffs = new_B - m_B ;		// differences with existing B
+	REAL diffNorm = diffs.norm2() ;	// Norm of this differences vector
+
+	return (diffNorm < 1e-10) ;		// Verify that this difference is very small
+}
+
+template<typename PFP>
+bool LocalFrame<PFP>::isOrthogonal()
+{
+	return (abs(m_T * m_B) < 1e-10) && (abs(m_N * m_B) < 1e-10) && (abs(m_T * m_N) < 1e-10) ;
+}
+
+template<typename PFP>
+bool LocalFrame<PFP>::isNormalized()
+{
+	return 		(1-1e-10 < m_N.norm2() && m_N.norm2() < 1+1e-10)
+			&& 	(1-1e-10 < m_T.norm2() && m_T.norm2() < 1+1e-10)
+			&&	(1-1e-10 < m_B.norm2() && m_B.norm2() < 1+1e-10) ;
+}
+
+template<typename PFP>
+bool LocalFrame<PFP>::isOrthoNormalDirect()
+{
+	return isOrthogonal() && isNormalized() && isDirect() ;
+}
+
+template<typename PFP>
+typename PFP::VEC2 LocalFrame<PFP>::carthToSpherical (const VEC3& carth) const
+{
+	VEC2 res ;
+
+	const REAL& x = carth[0] ;
+	const REAL& y = carth[1] ;
+	const REAL& z = carth[2] ;
+
+	REAL& theta = res[0] ;
+	REAL& phi = res[1] ;
+
+	phi = acos(z) ;
+	const REAL sinphi = sin(phi) ;
+	if (sinphi == 0.0)
+		theta = 0.0 ;
+	else
+		theta = ((y > 0) ? 1 : -1) * acos(std::min(REAL(1.0),std::max(REAL(-1.0),x / sinphi))) ;
+
+	assert (-(M_PI+0.000001) <= theta && theta <= M_PI+0.000001) ;
+	assert (-0.000001 < phi && phi <= M_PI+0.000001) ;
+	assert (!isnan(theta) || !"carthToSpherical : Theta is NaN !") ;
+	assert (!isnan(phi) || !"carthToSpherical : Phi is NaN !") ;
+
+	return res ;
+}
+
+template<typename PFP>
+typename PFP::VEC3 LocalFrame<PFP>::sphericalToCarth (const VEC2& sph) const
+{
+	VEC3 res ;
+
+	const REAL& theta = sph[0] ;
+	const REAL& phi = sph[1] ;
+
+	REAL& x = res[0] ;
+	REAL& y = res[1] ;
+	REAL& z = res[2] ;
+
+	x = cos(theta)*sin(phi) ;
+	y = sin(theta)*sin(phi) ;
+	z = cos(phi) ;
+
+	assert(-1.000001 < x && x < 1.000001) ;
+	assert(-1.000001 < y && y < 1.000001) ;
+	assert(-1.000001 < z && z < 1.000001) ;
+
+	return res ;
+}
+
+} // Utils
+
+} // CGoGN