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libsst/Lib/Include/CML/quaternion/quaternion.h
2026-04-03 00:22:39 -05:00

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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
*
* @todo Return a VectorXpr adaptor from the imaginary() method of
* quaternion and the expression node types.
*
* @todo swap multiplication order based upon template param
*
* @todo change element order based upon template param
*/
#ifndef quaternion_h
#define quaternion_h
#include <cml/mathlib/epsilon.h>
#include <cml/quaternion/quaternion_expr.h>
#include <cml/quaternion/quaternion_dot.h>
#include <cml/util.h>
/* This is used below to create a more meaningful compile-time error when
* the quaternion class is not created with a fixed-size 4-vector:
*/
struct quaternion_requires_fixed_size_array_type_error;
namespace cml {
/** A configurable quaternion type.
*
* @note Quaternions with two different orders cannot be used in the same
* expression.
*/
template<
typename Element,
class ArrayType,
class Order,
class Cross
>
class quaternion
{
/* The ArrayType must be fixed<> or external<>: */
CML_STATIC_REQUIRE_M(
(same_type< ArrayType, fixed<> >::is_true
|| same_type< ArrayType, external<> >::is_true),
quaternion_requires_fixed_size_array_type_error);
public:
/* Shorthand for the array type generator: */
typedef ArrayType storage_type;
typedef typename ArrayType::template rebind<4>::other generator_type;
/* Vector representing the quaternion. Use the rebinding template to
* set the vector size:
*/
typedef vector<Element, generator_type> vector_type;
/* Vector temporary type: */
typedef typename vector_type::temporary_type vector_temporary;
/* Quaternion order: */
typedef Order order_type;
/* Quaternion multiplication order: */
typedef Cross cross_type;
/* Scalar type representing the scalar part: */
typedef typename vector_type::value_type value_type;
typedef typename vector_type::reference reference;
typedef typename vector_type::const_reference const_reference;
/* XXX Need to verify that this is a true scalar type. */
/* The quaternion type: */
typedef quaternion<Element,storage_type,order_type,cross_type>
quaternion_type;
/* For integration into the expression template code: */
typedef quaternion_type expr_type;
/* For integration into the expression template code: */
typedef quaternion<
Element, typename vector_temporary::storage_type,
order_type, cross_type> temporary_type;
/* For integration into the expression templates code: */
typedef quaternion_type& expr_reference;
typedef const quaternion_type& expr_const_reference;
/* For matching by storage type: */
typedef typename vector_type::memory_tag memory_tag;
/* For matching by size type: */
typedef typename vector_type::size_tag size_tag;
/* Get the imaginary part type: */
typedef typename vector_temporary::subvector_type imaginary_type;
/* For matching by result-type: */
typedef cml::et::quaternion_result_tag result_tag;
/* For matching by assignability: */
typedef cml::et::assignable_tag assignable_tag;
public:
/** Record result size as an enum. */
enum { array_size = 4 };
/** Localize the ordering as an enum. */
enum {
W = order_type::W,
X = order_type::X,
Y = order_type::Y,
Z = order_type::Z
};
public:
/** Return the scalar part. */
value_type real() const { return m_q[W]; }
/** Return the imaginary vector. */
imaginary_type imaginary() const {
/*
imaginary_type v;
v[0] = m_q[X]; v[1] = m_q[Y]; v[2] = m_q[Z];
return v;
*/
return imaginary_type(m_q[X], m_q[Y], m_q[Z]);
}
/** Return the vector representing the quaternion. */
const vector_type& as_vector() const {
return m_q;
}
/** Return the Cayley norm of the quaternion. */
value_type norm() const {
return length_squared();
}
/** Return square of the quaternion length. */
value_type length_squared() const {
return cml::dot(*this,*this);
}
/** Return the quaternion length. */
value_type length() const {
return std::sqrt(length_squared());
}
/** Normalize this quaternion (divide by its length).
*
* @todo Make this return a QuaternionXpr.
*/
quaternion_type& normalize() {
return (*this /= length());
}
/** Set this quaternion to the conjugate. */
quaternion_type& conjugate() {
return (*this) = cml::conjugate(*this);
}
/** Set this quaternion to the inverse. */
quaternion_type& inverse() {
return (*this) = cml::inverse(*this);
}
/** Set this quaternion to the multiplicative identity. */
quaternion_type& identity() {
m_q[W] = value_type(1);
m_q[X] = value_type(0);
m_q[Y] = value_type(0);
m_q[Z] = value_type(0);
return *this;
}
/** Return the log of this quaternion. */
temporary_type log(
value_type tolerance = epsilon<value_type>::placeholder()) const
{
value_type a = acos_safe(real());
value_type s = std::sin(a);
if (s > tolerance) {
return temporary_type(value_type(0), imaginary() * (a / s));
} else {
return temporary_type(value_type(0), imaginary());
}
}
/**
* Return the result of the exponential function as applied to
* this quaternion.
*/
temporary_type exp(
value_type tolerance = epsilon<value_type>::placeholder()) const
{
imaginary_type v = imaginary();
value_type a = cml::length(v);
if (a > tolerance) {
return temporary_type(std::cos(a), v * (std::sin(a) / a));
} else {
return temporary_type(std::cos(a), v);
}
}
/** Const access to the quaternion as a vector. */
const_reference operator[](size_t i) const { return m_q[i]; }
/** Mutable access to the quaternion as a vector. */
reference operator[](size_t i) { return m_q[i]; }
/** Fill quaternion with random elements.
*
* @warning This does not generate uniformly random rotations.
*/
void random(value_type min, value_type max) {
for (size_t i = 0; i < 4; ++i) {
m_q[i] = random_real(min,max);
}
}
public:
/** Default initializer.
*
* @note The default constructor cannot be used with an external<>
* array type.
*/
quaternion() {}
/** Initializer for an external<> vector type. */
quaternion(Element* const array) : m_q(array) {}
/** Copy construct from the same type of quaternion. */
quaternion(const quaternion_type& q) : m_q(q.m_q) {}
/** Construct from a quaternion having a different array type. */
template<typename E, class AT> quaternion(
const quaternion<E,AT,order_type,cross_type>& q)
: m_q(q.as_vector()) {}
/** Copy construct from a QuaternionXpr. */
template<typename XprT> quaternion(QUATXPR_ARG_TYPE e) {
typedef typename XprT::order_type arg_order;
m_q[W] = e[arg_order::W];
m_q[X] = e[arg_order::X];
m_q[Y] = e[arg_order::Y];
m_q[Z] = e[arg_order::Z];
}
/** Initialize from a 4-vector.
*
* If Order is scalar_first, then v[0] is the real part. Otherwise,
* v[3] is the real part.
*/
quaternion(const vector_type& v) : m_q(v) {}
/** Initialize from an array of scalars.
*
* If Order is scalar_first, then v[0] is the real part. Otherwise,
* v[3] is the real part.
*
* @note The target vector must have CML_VEC_COPY_FROM_ARRAY
* implemented, so this cannot be used with external<> vectors.
*/
quaternion(const value_type v[4]) : m_q(v) {}
/** Initialize from 4 scalars.
*
* If Order is scalar_first, then a is the real part, and (b,c,d) is
* the imaginary part. Otherwise, (a,b,c) is the imaginary part, and d
* is the real part.
*/
quaternion(
const value_type& a, const value_type& b,
const value_type& c, const value_type& d)
{
/* Call the overloaded assignment function: */
assign(a, b, c, d, Order());
}
/** Initialize both the real and imaginary parts.
*
* The imaginary part is given by a 3-vector. Although the imaginary
* part is specified first, the proper coefficient order (vector or
* scalar first) is maintained.
*/
quaternion(const value_type& s, const imaginary_type& v) {
m_q[W] = s; m_q[X] = v[0]; m_q[Y] = v[1]; m_q[Z] = v[2];
}
/** Initialize both the real and imaginary parts.
*
* The imaginary part is given by a 3-vector. Although the imaginary
* part is specified second, the proper coefficient order (vector or
* scalar first) is maintained.
*/
quaternion(const imaginary_type& v, const value_type& s) {
m_q[W] = s; m_q[X] = v[0]; m_q[Y] = v[1]; m_q[Z] = v[2];
}
/** Initialize both the real and imaginary parts.
*
* The imaginary part is given by an array of scalars. Although the
* imaginary part is specified first, the proper coefficient order
* (vector or scalar first) is maintained.
*/
quaternion(const value_type v[3], const value_type& s) {
m_q[W] = s; m_q[X] = v[0]; m_q[Y] = v[1]; m_q[Z] = v[2];
}
/** Initialize both the real and imaginary parts.
*
* The imaginary part is given by an array of scalars. Although the
* imaginary part is specified second, the proper coefficient order
* (vector or scalar first) is maintained.
*/
quaternion(const value_type& s, const value_type v[3]) {
m_q[W] = s; m_q[X] = v[0]; m_q[Y] = v[1]; m_q[Z] = v[2];
}
/** Initialize from a VectorXpr. */
template<typename XprT>
quaternion(VECXPR_ARG_TYPE e) : m_q(e) {}
/** Initialize both the real and imaginary parts.
*
* The imaginary part is initialized with a VectorXpr.
*/
template<typename XprT>
quaternion(const value_type& s, VECXPR_ARG_TYPE e) {
m_q[W] = s; m_q[X] = e[0]; m_q[Y] = e[1]; m_q[Z] = e[2];
}
// @todo: Are we missing:
// quaternion(VECXPR_ARG_TYPE e, const value_type& s) {}
// Or is that covered elsewhere?
/** In-place op from a quaternion.
*
* This assumes that _op_ is defined for both the quaternion's vector
* type and its scalar type.
*/
#define CML_QUAT_ASSIGN_FROM_QUAT(_op_) \
template<typename E, class AT> const quaternion_type& \
operator _op_ (const quaternion<E,AT,order_type,cross_type>& q) { \
m_q[W] _op_ q[W]; \
m_q[X] _op_ q[X]; \
m_q[Y] _op_ q[Y]; \
m_q[Z] _op_ q[Z]; \
return *this; \
}
/** In-place op from a QuaternionXpr.
*
* This assumes that _op_ is defined for the quaternion's scalar type.
*/
#define CML_QUAT_ASSIGN_FROM_QUATXPR(_op_) \
template<typename XprT> quaternion_type& \
operator _op_ (QUATXPR_ARG_TYPE e) { \
typedef typename XprT::order_type arg_order; \
m_q[W] _op_ e[arg_order::W]; \
m_q[X] _op_ e[arg_order::X]; \
m_q[Y] _op_ e[arg_order::Y]; \
m_q[Z] _op_ e[arg_order::Z]; \
return *this; \
}
/** In-place op from a scalar type.
*
* This assumes that _op_ is defined for the quaternion's scalar type.
*/
#define CML_QUAT_ASSIGN_FROM_SCALAR(_op_,_op_name_) \
quaternion_type& operator _op_ (const value_type& s) { \
typedef _op_name_ <value_type,value_type> OpT; \
OpT().apply(m_q[W],s); \
OpT().apply(m_q[X],s); \
OpT().apply(m_q[Y],s); \
OpT().apply(m_q[Z],s); \
return *this; \
}
CML_QUAT_ASSIGN_FROM_QUAT(=)
CML_QUAT_ASSIGN_FROM_QUAT(+=)
CML_QUAT_ASSIGN_FROM_QUAT(-=)
CML_QUAT_ASSIGN_FROM_QUATXPR(=)
CML_QUAT_ASSIGN_FROM_QUATXPR(+=)
CML_QUAT_ASSIGN_FROM_QUATXPR(-=)
CML_QUAT_ASSIGN_FROM_SCALAR(*=, cml::et::OpMulAssign)
CML_QUAT_ASSIGN_FROM_SCALAR(/=, cml::et::OpDivAssign)
#undef CML_QUAT_ASSIGN_FROM_QUAT
#undef CML_QUAT_ASSIGN_FROM_QUATXPR
#undef CML_QUAT_ASSIGN_FROM_SCALAR
/** Accumulated multiplication with a quaternion.
*
* Compute p = p * q for two quaternions p and q.
*
* @internal Using operator* here is okay, as long as cml/quaternion.h
* is included before using this method (the only supported case for
* end-user code). This is because modern compilers won't instantiate a
* method in a template class until it is used, and including the main
* header ensures all definitions are available before any possible use
* of this method.
*/
quaternion_type& operator*=(const quaternion_type& q) {
return (*this = *this * q);
}
/** Accumulated multiplication with a quaternion expression.
*
* Compute p = p * e for a quaternion p and a quaternion expression e.
*
* @internal Using operator* here is okay, as long as cml/quaternion.h
* is included before using this method (the only supported case for
* end-user code). This is because modern compilers won't instantiate a
* method in a template class until it is used, and including the main
* header ensures all definitions are available before any possible use
* of this method.
*/
template<typename XprT> quaternion_type& operator*=(QUATXPR_ARG_TYPE e) {
return (*this = *this * e);
}
/** Return access to the data as a raw pointer. */
typename vector_type::pointer data() { return m_q.data(); }
/** Return access to the data as a const raw pointer. */
const typename vector_type::pointer data() const { return m_q.data(); }
/* NOTE: Quaternion division no longer supported, but I'm leaving the
code here for reference (Jesse) */
#if 0
/** Accumulated division with a quaternion.
*
* Compute p = p * inverse(q).
*
* @note Because quaternion multiplication is non-commutative, division
* is ambiguous. This method assumes a multiplication order consistent
* with the notational order; i.e. p = q / r means p = q*inverse(r).
*
* @internal Using operator* and cml::inverse here is okay, as long as
* cml/quaternion.h is included before using this method (the only
* supported case for end-user code). This is because modern compilers
* won't instantiate a method in a template class until it is used, and
* including the main header ensures all definitions are available
* before any possible use of this method.
*/
quaternion_type& operator/=(const quaternion_type& q) {
return (*this = *this * cml::inverse(q));
}
/** Accumulated division with a quaternion expression.
*
* Compute p = p * inverse(q).
*
* @note Because quaternion multiplication is non-commutative, division
* is ambiguous. This method assumes a multiplication order consistent
* with the notational order; i.e. p = q / r means p = q*inverse(r).
*
* @internal Using operator* and cml::inverse here is okay, as long as
* cml/quaternion.h is included before using this method (the only
* supported case for end-user code). This is because modern compilers
* won't instantiate a method in a template class until it is used, and
* including the main header ensures all definitions are available
* before any possible use of this method.
*/
template<typename XprT> quaternion_type& operator/=(QUATXPR_ARG_TYPE e) {
return (*this = *this * cml::inverse(e));
}
#endif
protected:
/** Overloaded function to assign the quaternion from 4 scalars. */
void assign(const value_type& a, const value_type& b,
const value_type& c, const value_type& d, scalar_first)
{
m_q[W] = a; m_q[X] = b; m_q[Y] = c; m_q[Z] = d;
}
/** Overloaded function to assign the quaternion from 4 scalars. */
void assign(const value_type& a, const value_type& b,
const value_type& c, const value_type& d, vector_first)
{
m_q[X] = a; m_q[Y] = b; m_q[Z] = c; m_q[W] = d;
}
protected:
vector_type m_q;
};
} // namespace cml
#endif
// -------------------------------------------------------------------------
// vim:ft=cpp