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simgear/simgear/math/SGVec2.hxx
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// Copyright (C) 2006-2009 Mathias Froehlich - Mathias.Froehlich@web.de
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library 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 PARTICULAR PURPOSE. See the GNU
// Library General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
#ifndef SGVec2_H
#define SGVec2_H
#include <iosfwd>
#include <simgear/math/SGLimits.hxx>
#include <simgear/math/SGMisc.hxx>
#include <simgear/math/SGMathFwd.hxx>
#include <simgear/math/simd.hxx>
/// 2D Vector Class
template<typename T>
class SGVec2 {
public:
typedef T value_type;
/// Default constructor. Does not initialize at all.
/// If you need them zero initialized, use SGVec2::zeros()
SGVec2(void)
{
/// Initialize with nans in the debug build, that will guarantee to have
/// a fast uninitialized default constructor in the release but shows up
/// uninitialized values in the debug build very fast ...
#ifndef NDEBUG
for (unsigned i = 0; i < 2; ++i)
data()[i] = SGLimits<T>::quiet_NaN();
#endif
}
/// Constructor. Initialize by the given values
SGVec2(T x, T y)
{ _data = simd4_t<T,2>(x, y); }
/// Constructor. Initialize by the content of a plain array,
/// make sure it has at least 2 elements
explicit SGVec2(const T* d)
{ _data = d ? simd4_t<T,2>(d) : simd4_t<T,2>(T(0)); }
template<typename S>
explicit SGVec2(const SGVec2<S>& d)
{ data()[0] = d[0]; data()[1] = d[1]; }
/// Access by index, the index is unchecked
const T& operator()(unsigned i) const
{ return data()[i]; }
/// Access by index, the index is unchecked
T& operator()(unsigned i)
{ return data()[i]; }
/// Access raw data by index, the index is unchecked
const T& operator[](unsigned i) const
{ return data()[i]; }
/// Access raw data by index, the index is unchecked
T& operator[](unsigned i)
{ return data()[i]; }
/// Access the x component
const T& x(void) const
{ return data()[0]; }
/// Access the x component
T& x(void)
{ return data()[0]; }
/// Access the y component
const T& y(void) const
{ return data()[1]; }
/// Access the y component
T& y(void)
{ return data()[1]; }
/// Access raw data
const T (&data(void) const)[2]
{ return _data.ptr(); }
/// Access raw data
T (&data(void))[2]
{ return _data.ptr(); }
const simd4_t<T,2> &simd2(void) const
{ return _data; }
/// Readonly raw storage interface
simd4_t<T,2> &simd2(void)
{ return _data; }
/// Inplace addition
SGVec2& operator+=(const SGVec2& v)
{ _data += v.simd2(); return *this; }
/// Inplace subtraction
SGVec2& operator-=(const SGVec2& v)
{ _data -= v.simd2(); return *this; }
/// Inplace scalar multiplication
template<typename S>
SGVec2& operator*=(S s)
{ _data *= s; return *this; }
/// Inplace scalar multiplication by 1/s
template<typename S>
SGVec2& operator/=(S s)
{ _data*=(1/T(s)); return *this; }
/// Return an all zero vector
static SGVec2 zeros(void)
{ return SGVec2(0, 0); }
/// Return unit vectors
static SGVec2 e1(void)
{ return SGVec2(1, 0); }
static SGVec2 e2(void)
{ return SGVec2(0, 1); }
private:
simd4_t<T,2> _data;
};
/// Unary +, do nothing ...
template<typename T>
inline
const SGVec2<T>&
operator+(const SGVec2<T>& v)
{ return v; }
/// Unary -, do nearly nothing
template<typename T>
inline
SGVec2<T>
operator-(SGVec2<T> v)
{ v *= -1; return v; }
/// Binary +
template<typename T>
inline
SGVec2<T>
operator+(SGVec2<T> v1, const SGVec2<T>& v2)
{ v1.simd2() += v2.simd2(); return v1; }
/// Binary -
template<typename T>
inline
SGVec2<T>
operator-(SGVec2<T> v1, const SGVec2<T>& v2)
{ v1.simd2() -= v2.simd2(); return v1; }
/// Scalar multiplication
template<typename S, typename T>
inline
SGVec2<T>
operator*(S s, SGVec2<T> v)
{ v.simd2() *= s; return v; }
/// Scalar multiplication
template<typename S, typename T>
inline
SGVec2<T>
operator*(SGVec2<T> v, S s)
{ v.simd2() *= s; return v; }
/// multiplication as a multiplicator, that is assume that the first vector
/// represents a 2x2 diagonal matrix with the diagonal elements in the vector.
/// Then the result is the product of that matrix times the second vector.
template<typename T>
inline
SGVec2<T>
mult(SGVec2<T> v1, const SGVec2<T>& v2)
{ v1.simd2() *= v2.simd2(); return v1; }
/// component wise min
template<typename T>
inline
SGVec2<T>
min(SGVec2<T> v1, const SGVec2<T>& v2)
{ v1.simd2() = simd4::min(v1.simd2(), v2.simd2()); return v1; }
template<typename S, typename T>
inline
SGVec2<T>
min(SGVec2<T> v, S s)
{ v.simd2() = simd4::min(v.simd2(), simd4_t<T,2>(s)); return v; }
template<typename S, typename T>
inline
SGVec2<T>
min(S s, SGVec2<T> v)
{ v.sim2() = simd4::min(v.simd2(), simd4_t<T,2>(s)); return v; }
/// component wise max
template<typename T>
inline
SGVec2<T>
max(SGVec2<T> v1, const SGVec2<T>& v2)
{ v1.simd2() = simd4::max(v1.simd2(), v2.simd2()); return v1; }
template<typename S, typename T>
inline
SGVec2<T>
max(const SGVec2<T>& v, S s)
{ v = simd4::max(v.simd2(), simd4_t<T,2>(s)); return v; }
template<typename S, typename T>
inline
SGVec2<T>
max(S s, const SGVec2<T>& v)
{ v = simd4::max(v.simd2(), simd4_t<T,2>(s)); return v; }
/// Add two vectors taking care of (integer) overflows. The values are limited
/// to the respective minimum and maximum values.
template<class T>
SGVec2<T> addClipOverflow(SGVec2<T> const& lhs, SGVec2<T> const& rhs)
{
return SGVec2<T>(
SGMisc<T>::addClipOverflow(lhs.x(), rhs.x()),
SGMisc<T>::addClipOverflow(lhs.y(), rhs.y())
);
}
/// Scalar dot product
template<typename T>
inline
T
dot(const SGVec2<T>& v1, const SGVec2<T>& v2)
{ return simd4::dot(v1.simd2(), v2.simd2()); }
/// The euclidean norm of the vector, that is what most people call length
template<typename T>
inline
T
norm(const SGVec2<T>& v)
{ return simd4::magnitude(v.simd2()); }
/// The euclidean norm of the vector, that is what most people call length
template<typename T>
inline
T
length(const SGVec2<T>& v)
{ return simd4::magnitude(v.simd2()); }
/// The 1-norm of the vector, this one is the fastest length function we
/// can implement on modern cpu's
template<typename T>
inline
T
norm1(SGVec2<T> v)
{ v.simd2() = simd4::abs(v.simd2()); return (v(0)+v(1)); }
/// The inf-norm of the vector
template<typename T>
inline
T
normI(SGVec2<T> v)
{
v.simd2() = simd4::abs(v.simd2());
return SGMisc<T>::max(v(0), v(1));
}
/// The euclidean norm of the vector, that is what most people call length
template<typename T>
inline
SGVec2<T>
normalize(const SGVec2<T>& v)
{
T normv = norm(v);
if (normv <= SGLimits<T>::min())
return SGVec2<T>::zeros();
return (1/normv)*v;
}
/// Return true if exactly the same
template<typename T>
inline
bool
operator==(const SGVec2<T>& v1, const SGVec2<T>& v2)
{ return v1(0) == v2(0) && v1(1) == v2(1); }
/// Return true if not exactly the same
template<typename T>
inline
bool
operator!=(const SGVec2<T>& v1, const SGVec2<T>& v2)
{ return ! (v1 == v2); }
/// Return true if smaller, good for putting that into a std::map
template<typename T>
inline
bool
operator<(const SGVec2<T>& v1, const SGVec2<T>& v2)
{
if (v1(0) < v2(0)) return true;
else if (v2(0) < v1(0)) return false;
else return (v1(1) < v2(1));
}
template<typename T>
inline
bool
operator<=(const SGVec2<T>& v1, const SGVec2<T>& v2)
{
if (v1(0) < v2(0)) return true;
else if (v2(0) < v1(0)) return false;
else return (v1(1) <= v2(1));
}
template<typename T>
inline
bool
operator>(const SGVec2<T>& v1, const SGVec2<T>& v2)
{ return operator<(v2, v1); }
template<typename T>
inline
bool
operator>=(const SGVec2<T>& v1, const SGVec2<T>& v2)
{ return operator<=(v2, v1); }
/// Return true if equal to the relative tolerance tol
template<typename T>
inline
bool
equivalent(const SGVec2<T>& v1, const SGVec2<T>& v2, T rtol, T atol)
{ return norm1(v1 - v2) < rtol*(norm1(v1) + norm1(v2)) + atol; }
/// Return true if equal to the relative tolerance tol
template<typename T>
inline
bool
equivalent(const SGVec2<T>& v1, const SGVec2<T>& v2, T rtol)
{ return norm1(v1 - v2) < rtol*(norm1(v1) + norm1(v2)); }
/// Return true if about equal to roundoff of the underlying type
template<typename T>
inline
bool
equivalent(const SGVec2<T>& v1, const SGVec2<T>& v2)
{
T tol = 100*SGLimits<T>::epsilon();
return equivalent(v1, v2, tol, tol);
}
/// The euclidean distance of the two vectors
template<typename T>
inline
T
dist(const SGVec2<T>& v1, const SGVec2<T>& v2)
{ return simd4::magnitude(v1.simd2() - v2.simd2()); }
/// The squared euclidean distance of the two vectors
template<typename T>
inline
T
distSqr(SGVec2<T> v1, const SGVec2<T>& v2)
{ return simd4::magnitude2(v1.simd2() - v2.simd2()); }
// calculate the projection of u along the direction of d.
template<typename T>
inline
SGVec2<T>
projection(const SGVec2<T>& u, const SGVec2<T>& d)
{
T denom = simd4::magnitude2(d.simd2());
T ud = dot(u, d);
if (SGLimits<T>::min() < denom) return u;
else return d * (dot(u, d) / denom);
}
template<typename T>
inline
SGVec2<T>
interpolate(T tau, const SGVec2<T>& v1, const SGVec2<T>& v2)
{
SGVec2<T> r;
r.simd2() = simd4::interpolate(tau, v1.simd2(), v2.simd2());
return r;
}
// Helper function for point_in_triangle
template <typename T>
inline
T
pt_determine(const SGVec2<T>& pt1, const SGVec2<T>& pt2, const SGVec2<T>& pt3)
{
return (pt1.x()-pt3.x()) * (pt2.y()-pt3.y()) - (pt2.x() - pt3.x()) * (pt1.y() - pt3.y());
}
// Is testpt inside the triangle formed by the other three points?
template <typename T>
inline
bool
point_in_triangle(const SGVec2<T>& testpt, const SGVec2<T>& pt1, const SGVec2<T>& pt2, const SGVec2<T>& pt3)
{
T d1 = pt_determine(testpt,pt1,pt2);
T d2 = pt_determine(testpt,pt2,pt3);
T d3 = pt_determine(testpt,pt3,pt1);
bool has_neg = (d1 < 0) || (d2 < 0) || (d3 < 0);
bool has_pos = (d1 > 0) || (d2 > 0) || (d3 > 0);
return !(has_neg && has_pos);
}
#ifndef NDEBUG
template<typename T>
inline
bool
isNaN(const SGVec2<T>& v)
{
return SGMisc<T>::isNaN(v(0)) || SGMisc<T>::isNaN(v(1));
}
#endif
/// Output to an ostream
template<typename char_type, typename traits_type, typename T>
inline
std::basic_ostream<char_type, traits_type>&
operator<<(std::basic_ostream<char_type, traits_type>& s, const SGVec2<T>& v)
{ return s << "[ " << v(0) << ", " << v(1) << " ]"; }
inline
SGVec2f
toVec2f(const SGVec2d& v)
{ SGVec2f f(v); return f; }
inline
SGVec2d
toVec2d(const SGVec2f& v)
{ SGVec2d d(v); return d; }
#endif