Merge pull request #3 from saurabhb17/master

secondary files

1 files changed, 129 insertions, 0 deletions

diff --git a/include/ttl/ttl_util.h b/include/ttl/ttl_util.h
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+/*
+ * 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_