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Lib/Include/CML/quaternion/quaternion_functions.h

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+/* -*- C++ -*- ------------------------------------------------------------
+ 
+Copyright (c) 2007 Jesse Anders and Demian Nave http://cmldev.net/
+
+The Configurable Math Library (CML) is distributed under the terms of the
+Boost Software License, v1.0 (see cml/LICENSE for details).
+
+ *-----------------------------------------------------------------------*/
+/** @file
+ *  @brief Functions on quaternions.
+ *
+ * @todo The functions that return quaternions and vectors should be changed
+ * to return quaternion expression nodes, as should the corresponding
+ * class methods.
+ */
+
+#ifndef quaternion_functions_h
+#define quaternion_functions_h
+
+#include <cml/mathlib/checking.h> // For CheckQuat()
+#include <cml/mathlib/epsilon.h>
+#include <cml/util.h> // For acos_safe()
+
+namespace cml {
+
+/** Returns the real part of the quaternion. */
+template<typename E, class AT, class OT, class CT>
+inline typename quaternion<E,AT,OT,CT>::value_type
+real(const quaternion<E,AT,OT,CT>& q)
+{
+    return q.real();
+}
+
+/** Returns the real (scalar) part of the QuaternionXpr. */
+template<typename XprT>
+inline typename et::QuaternionXpr<XprT>::value_type
+real(const et::QuaternionXpr<XprT>& e)
+{
+    return e.real();
+}
+
+/** Returns the imaginary (vector) part of the quaternion. */
+template<typename E, class AT, class OT, class CT>
+inline typename quaternion<E,AT,OT,CT>::imaginary_type
+imaginary(const quaternion<E,AT,OT,CT>& q)
+{
+    return q.imaginary();
+}
+
+/** Returns the imaginary (vector) part of the QuaternionXpr. */
+template<typename XprT>
+//inline typename et::QuaternionXpr<XprT>::temporary_type
+inline typename et::QuaternionXpr<XprT>::imaginary_type
+imaginary(const et::QuaternionXpr<XprT>& e)
+{
+    return e.imaginary();
+}
+
+/** Cayley norm of a quaternion. */
+template<typename E, class AT, class OT, class CT>
+inline typename quaternion<E,AT,OT,CT>::value_type
+norm(const quaternion<E,AT,OT,CT>& arg)
+{
+    return arg.length_squared();
+}
+
+/** Cayley norm of a QuaternionXpr. */
+template<typename XprT>
+inline typename XprT::value_type
+norm(QUATXPR_ARG_TYPE arg)
+{
+    return arg.length_squared();
+}
+
+/** Squared length of a quaternion. */
+template<typename E, class AT, class OT, class CT>
+inline typename quaternion<E,AT,OT,CT>::value_type
+length_squared(const quaternion<E,AT,OT,CT>& arg)
+{
+    return arg.length_squared();
+}
+
+/** Squared length of a quaternion expr. */
+template<typename XprT>
+inline typename XprT::value_type
+length_squared(QUATXPR_ARG_TYPE arg)
+{
+    return arg.length_squared();
+}
+
+/** Length of a quaternion. */
+template<typename E, class AT, class OT, class CT>
+inline typename quaternion<E,AT,OT,CT>::value_type
+length(const quaternion<E,AT,OT,CT>& arg)
+{
+    return arg.length();
+}
+
+/** Length of a quaternion expr. */
+template<typename XprT>
+inline typename XprT::value_type
+length(QUATXPR_ARG_TYPE arg)
+{
+    return arg.length();
+}
+
+/** Normalize a quaternion.
+ *
+ * The input quaternion is not changed.
+ */
+template<typename E, class AT, class OT, class CT>
+inline quaternion<E,AT,OT,CT>
+normalize(const quaternion<E,AT,OT,CT>& arg)
+{
+    typename quaternion<E,AT,OT,CT>::temporary_type result(arg);
+    result.normalize();
+    return result;
+}
+
+/** Normalize a quaternion expr. */
+template<typename XprT>
+inline typename XprT::temporary_type
+normalize(QUATXPR_ARG_TYPE arg)
+{
+    return arg.normalize();
+}
+
+/** Set a quaternion to the multiplicative identity.
+ *
+ * The input quaternion is not changed.
+ */
+template<typename E, class AT, class OT, class CT>
+inline quaternion<E,AT,OT,CT>
+identity(const quaternion<E,AT,OT,CT>& arg)
+{
+    typename quaternion<E,AT,OT,CT>::temporary_type result(arg);
+    result.identity();
+    return result;
+}
+
+/** Log of a quaternion or quaternion expression.
+ */
+template < class QuatT >
+typename QuatT::temporary_type log(
+    const QuatT& q,
+    typename QuatT::value_type tolerance =
+        epsilon<typename QuatT::value_type>::placeholder())
+{
+    detail::CheckQuat(q);
+
+    return q.log();
+}
+
+/** Exponential function of a quaternion or quaternion expression.
+ */
+template < class QuatT >
+typename QuatT::temporary_type exp(
+    const QuatT& q,
+    typename QuatT::value_type tolerance =
+        epsilon<typename QuatT::value_type>::placeholder())
+{
+    detail::CheckQuat(q);
+
+    return q.exp();
+}
+
+} // namespace cml
+
+#endif
+
+// -------------------------------------------------------------------------
+// vim:ft=cpp