From 8b2aa1b5301ab60368a03e36df4ff5216726e87d Mon Sep 17 00:00:00 2001
From: toma <toma@283d02a7-25f6-0310-bc7c-ecb5cbfe19da>
Date: Wed, 25 Nov 2009 17:56:58 +0000
Subject: Copy the KDE 3.5 branch to branches/trinity for new KDE 3.5 features.
 BUG:215923

git-svn-id: svn://anonsvn.kde.org/home/kde/branches/trinity/kdeartwork@1054174 283d02a7-25f6-0310-bc7c-ecb5cbfe19da
---
 kscreensaver/kdesavers/vec3.h | 214 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 214 insertions(+)
 create mode 100644 kscreensaver/kdesavers/vec3.h

(limited to 'kscreensaver/kdesavers/vec3.h')

diff --git a/kscreensaver/kdesavers/vec3.h b/kscreensaver/kdesavers/vec3.h
new file mode 100644
index 00000000..62aeb8ed
--- /dev/null
+++ b/kscreensaver/kdesavers/vec3.h
@@ -0,0 +1,214 @@
+//============================================================================
+//
+// 3-dim real vector class
+// $Id$
+// Copyright (C) 2004 Georg Drenkhahn
+//
+// This file is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License version 2 as published by the
+// Free Software Foundation.
+//
+//============================================================================
+
+#ifndef VEC3_H
+#define VEC3_H
+
+#include <valarray>
+
+/** @brief 3-dimensional real vector
+ *
+ * Implements regular 3 dimensional (space) vectors including the common inner
+ * scalar product (2 norm) and the cross product.  @a T may be any integer or
+ * float data type which is an acceptable template argument of std::valarray. */
+template<typename T>
+class vec3 : public std::valarray<T>
+{
+  public:
+   /** Default constructor */
+   vec3();
+   /** Constructor with initial element values */
+   vec3(const T&, const T&, const T&);
+   /** Copy constructor */
+   vec3(const std::valarray<T>&);
+   /** Copy constructor */
+   vec3(const std::slice_array<T>&);
+
+   /** Normalize the vector to have a norm of 1.  @return Normalized vector if
+    * length is non-zero and otherwise the zero vector. */
+   vec3& normalize();
+
+   /** Rotate the vector (*this) in positive mathematical direction around the
+    * direction given by @a r.  The norm of @a r specifies the rotation angle in
+    * radians.
+    * @param r Rotation vector.
+    * @return Rotated vector. */
+   vec3& rotate(const vec3& r);
+
+   /*--- static funcions ---*/
+
+   /** @param a first vector
+    * @param b second vector
+    * @return Cosine of the angle between @a a and @a b.  If norm(@a a)==0 or
+    * norm(@a b)==0 the global variable errno is set to EDOM and NAN (or
+    * std::numeric_limits<T>::quiet_NaN()) is returned. */
+   static T cos_angle(const vec3& a, const vec3& b);
+
+   /** @brief Returns the angle between vectors @c a and @a b but with respect
+    * to a preferred rotation direction @a c.
+    *
+    * @param a First vector for angle.  Must be | @a a |>0 otherwises NAN is
+    * returned.
+    * @param b Second vector for angle.  Must be | @a b |>0 otherwises NAN is
+    * returned.
+    * @param c Indicates the rotation direction. @a c can be any vector which is
+    * not part of the plane spanned by @a a and @a b.  If | @a c | = 0 the
+    * smalest possible angle angle is returned.
+    * @return Angle in radians between 0 and 2*Pi or NAN if | @a a |=0 or | @a b
+    * |=0.
+    *
+    * For @a a not parallel to @a b and @a a not antiparallel to @a b the 2
+    * vectors @a a,@a b span a unique plane in the 3-dimensional space.  Let @b
+    * n<sub>1</sub> and @b n<sub>2</sub> be the two possible normal vectors for
+    * this plane with |@b n<sub>i</sub> |=1, i={1,2} and @b n<sub>1</sub> = -@b
+    * n<sub>2</sub> .
+    *
+    * Let further @a a and @a b enclose an angle alpha in [0,Pi], then there is
+    * one i in {1,2} so that (alpha*@b n<sub>i</sub> x @a a) * @a b = 0.  This
+    * means @a a rotated by the rotation vector alpha*@b n<sub>i</sub> is
+    * parallel to @a b.  One could also rotate @a a by (2*Pi-alpha)*(-@b
+    * n<sub>i</sub>) to acomplish the same transformation with
+    * ((2*Pi-alpha)*(-@b n<sub>i</sub>) x @a a) * @a b = 0
+    *
+    * The vector @a c defines the direction of the normal vector to take as
+    * reference.  If @a c * @b n<sub>i</sub> > 0 alpha is returned and otherwise
+    * 2*Pi-alpha.  If @a a parallel to @a b or @a a parallel to @a b the choice
+    * of @a c does not matter. */
+   static T angle(const vec3& a, const vec3& b, const vec3& c);
+
+   /*--- static inline funcions ---*/
+
+   /** Norm of argument vector.
+    * @param a vector.
+    * @return | @a a | */
+   static T norm(const vec3& a);
+
+   /** Angle between @a a and @a b.
+    * @param a fist vector.  Must be | @a a | > 0 otherwises NAN is returned.
+    * @param b second vector.  Must be | @a b | > 0 otherwises NAN is returned.
+    * @return Angle in radians between 0 and Pi or NAN if | @a a | = 0 or | @a b
+    * | = 0. */
+   static T angle(const vec3& a, const vec3& b);
+
+   /** Cross product of @a a and @a b.
+    * @param a fist vector.
+    * @param b second vector.
+    * @return Cross product of argument vectors @a a x @a b. */
+   static vec3 crossprod(const vec3& a, const vec3& b);
+
+   /** Normalized version of argument vector.
+    * @param a vector.
+    * @return @a a / | @a a | for | @a a | > 0 and otherwise the zero vector
+    * (=@a a).  In the latter case the global variable errno is set to EDOM. */
+   static vec3 normalized(vec3 a);
+};
+
+/*--- inline member functions ---*/
+
+template<typename T>
+inline vec3<T>::vec3()
+   : std::valarray<T>(3)
+{}
+
+template<typename T>
+inline vec3<T>::vec3(const T& a, const T& b, const T& c)
+   : std::valarray<T>(3)
+{
+   (*this)[0] = a;
+   (*this)[1] = b;
+   (*this)[2] = c;
+}
+
+template<typename T>
+inline vec3<T>::vec3(const std::valarray<T>& a)
+   : std::valarray<T>(a)
+{
+}
+
+template<typename T>
+inline vec3<T>::vec3(const std::slice_array<T>& a)
+   : std::valarray<T>(a)
+{
+}
+
+/*--- inline non-member operators ---*/
+
+/** @param a first vector summand
+ * @param b second vector summand
+ * @return Sum vector of vectors @a a and @a b. */
+template<typename T>
+inline vec3<T> operator+(vec3<T> a, const vec3<T>& b)
+{
+   a += b;   /* valarray<T>::operator+=(const valarray<T>&) */
+   return a;
+}
+
+/** @param a first vector multiplicant
+ * @param b second vector multiplicant
+ * @return Scalar product of vectors @a a and @a b. */
+template<typename T>
+inline T operator*(vec3<T> a, const vec3<T>& b)
+{
+   a *= b;   /* valarray<T>::operator*=(const T&) */
+   return a.sum();
+}
+
+/** @param a scalar multiplicant
+ * @param b vector operand
+ * @return Product vector of scalar @a a and vector @a b. */
+template<typename T>
+inline vec3<T> operator*(const T& a, vec3<T> b)
+{
+   b *= a;    /* valarray<T>::operator*=(const T&) */
+   return b;
+}
+
+/** @param a vector operand
+ * @param b scalar multiplicant
+ * @return Product vector of scalar @a b and vector @a a. */
+template<typename T>
+inline vec3<T> operator*(vec3<T> a, const T& b)
+{
+   return b*a; /* vec3<T>::operator*(const T&, vec3<T>) */
+}
+
+/*--- static inline funcions ---*/
+
+template<typename T>
+inline T vec3<T>::norm(const vec3<T>& a)
+{
+   return sqrt(a*a);
+}
+
+template<typename T>
+inline T vec3<T>::angle(const vec3<T>& a, const vec3<T>& b)
+{
+   // returns NAN if cos_angle() returns NAN (TODO: test this case)
+   return acos(cos_angle(a,b));
+}
+
+template<typename T>
+inline vec3<T> vec3<T>::crossprod(const vec3<T>& a, const vec3<T>& b)
+{
+   return vec3<T>(
+      a[1]*b[2] - a[2]*b[1],
+      a[2]*b[0] - a[0]*b[2],
+      a[0]*b[1] - a[1]*b[0]);
+}
+
+template<typename T>
+inline vec3<T> vec3<T>::normalized(vec3<T> a)
+{
+   return a.normalize();
+}
+
+#endif
-- 
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