libcruft-util/point.hpp

126 lines
4.1 KiB
C++

/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2011-2016 Danny Robson <danny@nerdcruft.net>
*/
#ifndef __UTIL_POINT_HPP
#define __UTIL_POINT_HPP
#include "vector.hpp"
#include "coord.hpp"
#include <type_traits>
namespace util {
/// An n-dimensional position in space.
///
/// \tparam S number of dimensions
/// \tparam T the underlying per-dimension datatype
template <size_t S, typename T>
struct point : public coord::base<S,T,point,coord::xyzw>
{
using coord::base<S,T,util::point,coord::xyzw>::base;
vector<S,T> to (point) const;
vector<S,T> from (point) const;
template <size_t D> point<D,T> homog (void) const;
static constexpr point<S,T> origin (void);
void sanity (void) const;
};
///////////////////////////////////////////////////////////////////////////
// distance operators
/// computes the exact euclidean distance between two points.
template <size_t S, typename T, typename U>
typename std::common_type<T,U>::type distance (point<S,T>, point<S,U>);
/// computes the squared euclidean distance between two points.
///
/// useful if you just need to compare distances because it avoids a sqrt
/// operation.
template <size_t S, typename T, typename U>
constexpr typename std::common_type<T,U>::type distance2 (point<S,T>, point<S,U>);
/// computes the octile distance between two points. that is, the shortest
/// distance between `a' and `b' where travel is only allowed beween the 8
/// grid neighbours and cost for diagonals is proportionally larger than
/// cardinal movement. see also: chebyshev.
template <typename T, typename U>
typename std::common_type<T,U>::type octile (point<2,T>, point<2,U>);
/// computes the manhattan distance between two points. that is, the
/// distance where travel is only allowed along cardinal directions.
template <size_t S, typename T, typename U>
constexpr typename std::common_type<T,U>::type manhattan (point<S,T>, point<S,U>);
/// computes the cheyvshev distance between two points. that is, the
/// shortest distance between `a' and `b' where travel is only allowed
/// between the 8 grid neighbours and cost for diagonals is the same as
/// cardinal movement. see also: octile.
template <size_t S, typename T, typename U>
constexpr typename std::common_type<T,U>::type chebyshev (point<S,T>, point<S,U>);
// Convenience typedefs
template <typename T> using point1 = point<1,T>;
template <typename T> using point2 = point<2,T>;
template <typename T> using point3 = point<3,T>;
template <typename T> using point4 = point<4,T>;
template <size_t S> using pointi = point<S,int>;
template <size_t S> using pointf = point<S,float>;
typedef point1<float> point1f;
typedef point2<float> point2f;
typedef point3<float> point3f;
typedef point4<float> point4f;
typedef point2<double> point2d;
typedef point3<double> point3d;
typedef point4<double> point4d;
typedef point1<unsigned> point1u;
typedef point2<unsigned> point2u;
typedef point3<unsigned> point3u;
typedef point4<unsigned> point4u;
typedef point2<int> point2i;
typedef point3<int> point3i;
typedef point4<int> point4i;
}
#include <functional>
namespace std {
template <size_t S, typename T>
struct hash<util::point<S,T>> {
size_t operator() (util::point<S,T> p) const {
std::hash<T> h;
size_t k = 0;
for (size_t i = 0; i < S; ++i)
k = h (p.data[i] ^ k);
return k;
}
};
}
#include "point.ipp"
#endif // __UTIL_POINT_HPP