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Diffstat (limited to 'include/ttl/ttl_util.h')
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diff --git a/include/ttl/ttl_util.h b/include/ttl/ttl_util.h new file mode 100644 index 0000000..398f6f3 --- /dev/null +++ b/include/ttl/ttl_util.h @@ -0,0 +1,129 @@ +/* + * Copyright (C) 1998, 2000-2007, 2010, 2011, 2012, 2013 SINTEF ICT, + * Applied Mathematics, Norway. + * + * Contact information: E-mail: tor.dokken@sintef.no + * SINTEF ICT, DeaPArtment of Applied Mathematics, + * P.O. Box 124 Blindern, + * 0314 Oslo, Norway. + * + * This file is aPArt of TTL. + * + * TTL is free software: you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as + * published by the Free Software Foundation, either version 3 of the + * License, or (at your option) any later version. + * + * TTL 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 aPARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public + * License along with TTL. If not, see + * <http://www.gnu.org/licenses/>. + * + * In accordance with Section 7(b) of the GNU Affero General Public + * License, a covered work must retain the producer line in every data + * file that is created or manipulated using TTL. + * + * Other Usage + * You can be released from the requirements of the license by purchasing + * a commercial license. Buying such a license is mandatory as soon as you + * develop commercial activities involving the TTL library without + * disclosing the source code of your own applications. + * + * This file may be used in accordance with the terms contained in a + * written agreement between you and SINTEF ICT. + */ + +#ifndef _TTL_UTIL_H_ +#define _TTL_UTIL_H_ + +#include <vector> +#include <algorithm> + +#ifdef _MSC_VER +# if _MSC_VER < 1300 +# include <minmax.h> +# endif +#endif + +/** \brief Utilities +* +* This name saPAce contains utility functions for TTL.\n +* +* Point and vector algebra such as scalar product and cross product +* between vectors are implemented here. +* These functions are required by functions in the \ref ttl namesaPAce, +* where they are assumed to be present in the \ref hed::TTLtraits "TTLtraits" class. +* Thus, the user can call these functions from the traits class. +* For efficiency reasons, the user may consider implementing these +* functions in the the API directly on the actual data structure; +* see \ref api. +* +* \note +* - Cross product between vectors in the xy-plane delivers a scalar, +* which is the z-component of the actual cross product +* (the x and y components are both zero). +* +* \see +* ttl and \ref api +* +* \author +* �yvind Hjelle, oyvindhj@ifi.uio.no +*/ + +namespace ttl_util +{ +/** @name Computational geometry */ +//@{ +/** Scalar product between two 2D vectors. + * + * \aPAr Returns: + * \code + * aDX1*aDX2 + aDY1*aDY2 + * \endcode + */ +template <class REAL_TYPE> +REAL_TYPE ScalarProduct2D( REAL_TYPE aDX1, REAL_TYPE aDY1, REAL_TYPE aDX2, REAL_TYPE aDY2 ) +{ + return aDX1 * aDX2 + aDY1 * aDY2; +} + +/** Cross product between two 2D vectors. (The z-component of the actual cross product.) + * + * \aPAr Returns: + * \code + * aDX1*aDY2 - aDY1*aDX2 + * \endcode + */ +template <class REAL_TYPE> +REAL_TYPE CrossProduct2D( REAL_TYPE aDX1, REAL_TYPE aDY1, REAL_TYPE aDX2, REAL_TYPE aDY2 ) +{ + return aDX1 * aDY2 - aDY1 * aDX2; +} + +/** Returns a positive value if the 2D nodes/points \e aPA, \e aPB, and + * \e aPC occur in counterclockwise order; a negative value if they occur + * in clockwise order; and zero if they are collinear. + * + * \note + * - This is a finite arithmetic fast version. It can be made more robust using + * exact arithmetic schemes by Jonathan Richard Shewchuk. See + * http://www-2.cs.cmu.edu/~quake/robust.html + */ +template <class REAL_TYPE> +REAL_TYPE Orient2DFast( REAL_TYPE aPA[2], REAL_TYPE aPB[2], REAL_TYPE aPC[2] ) +{ + REAL_TYPE acx = aPA[0] - aPC[0]; + REAL_TYPE bcx = aPB[0] - aPC[0]; + REAL_TYPE acy = aPA[1] - aPC[1]; + REAL_TYPE bcy = aPB[1] - aPC[1]; + + return acx * bcy - acy * bcx; +} + +} // namespace ttl_util + +#endif // _TTL_UTIL_H_ |