--- /dev/null
+/* -*- 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
+ */
+
+#ifndef quaternion_basis_h
+#define quaternion_basis_h
+
+#include <cml/mathlib/checking.h>
+
+/* Functions for getting the basis vectors of a quaternion rotation. */
+
+namespace cml {
+
+/** Get the i'th basis vector of a quaternion rotation */
+template < class QuatT > vector< typename QuatT::value_type, fixed<3> >
+quaternion_get_basis_vector(const QuatT& q, size_t i)
+{
+ typedef QuatT quaternion_type;
+ typedef typename quaternion_type::value_type value_type;
+ typedef typename quaternion_type::order_type order_type;
+ typedef vector< value_type, fixed<3> > vector_type;
+
+ /* Checking */
+ detail::CheckQuat(q);
+ detail::CheckIndex3(i);
+
+ size_t j, k;
+ cyclic_permutation(i, i, j, k);
+
+ /* @todo: Clean this up. */
+ const size_t W = order_type::W;
+ const size_t I = order_type::X + i;
+ const size_t J = order_type::X + j;
+ const size_t K = order_type::X + k;
+
+ value_type j2 = q[J] + q[J];
+ value_type k2 = q[K] + q[K];
+
+ /* @todo: use set_permuted() for the following when available. */
+
+ vector_type result;
+ result[i] = value_type(1) - q[J] * j2 - q[K] * k2;
+ result[j] = q[I] * j2 + q[W] * k2;
+ result[k] = q[I] * k2 - q[W] * j2;
+ return result;
+}
+
+/** Get the x basis vector of a quaternion rotation */
+template < class QuatT > vector< typename QuatT::value_type, fixed<3> >
+quaternion_get_x_basis_vector(const QuatT& q) {
+ return quaternion_get_basis_vector(q,0);
+}
+
+/** Get the y basis vector of a quaternion rotation */
+template < class QuatT > vector< typename QuatT::value_type, fixed<3> >
+quaternion_get_y_basis_vector(const QuatT& q) {
+ return quaternion_get_basis_vector(q,1);
+}
+
+/** Get the z basis vector of a quaternion rotation */
+template < class QuatT > vector< typename QuatT::value_type, fixed<3> >
+quaternion_get_z_basis_vector(const QuatT& q) {
+ return quaternion_get_basis_vector(q,2);
+}
+
+/** Get the basis vectors of a quaternion rotation */
+template < class QuatT, typename E, class A > void
+quaternion_get_basis_vectors(
+ const QuatT& q,
+ vector<E,A>& x,
+ vector<E,A>& y,
+ vector<E,A>& z)
+{
+ x = quaternion_get_x_basis_vector(q);
+ y = quaternion_get_y_basis_vector(q);
+ z = quaternion_get_z_basis_vector(q);
+}
+
+} // namespace cml
+
+#endif