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point: prefer explicit over blocked namespacing

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Danny Robson 2016-12-12 15:45:43 +11:00
parent 9711272989
commit 17b5514df4
1 changed files with 93 additions and 95 deletions
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188
point.ipp
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@ -18,104 +18,102 @@
#include <algorithm> #include <algorithm>
namespace util { ///------------------------------------------------------------------------
///------------------------------------------------------------------------ /// expand point to use homogenous coordinates of a higher dimension.
/// expand point to use homogenous coordinates of a higher dimension. /// ie, fill with (0,..,0,1)
/// ie, fill with (0,..,0,1) template <size_t S, typename T>
template <size_t S, typename T> template <size_t D>
template <size_t D> util::point<D,T>
point<D,T> util::point<S,T>::homog (void) const
point<S,T>::homog (void) const {
{ static_assert (D > S, "homog will not overwrite data");
static_assert (D > S, "homog will not overwrite data");
point<D,T> out; point<D,T> out;
// Copy the existing data // Copy the existing data
auto c = std::copy (this->begin (), auto c = std::copy (this->begin (),
this->end (), this->end (),
out.begin ()); out.begin ());
// Fill until the second last element with zeros // Fill until the second last element with zeros
auto f = std::fill_n (c, D - S - 1, T{0}); auto f = std::fill_n (c, D - S - 1, T{0});
// Last element should be one // Last element should be one
*f = T{1}; *f = T{1};
return out; return out;
} }
//------------------------------------------------------------------------- //-------------------------------------------------------------------------
template <size_t S, typename T, typename U> template <size_t S, typename T, typename U>
typename std::common_type<T,U>::type typename std::common_type<T,U>::type
distance (point<S,T> a, point<S,U> b) util::distance (point<S,T> a, point<S,U> b)
{ {
using type_t = typename std::common_type<T,U>::type; using type_t = typename std::common_type<T,U>::type;
static_assert (std::is_floating_point<type_t>::value, static_assert (std::is_floating_point<type_t>::value,
"sqrt likely requires fractional types"); "sqrt likely requires fractional types");
return std::sqrt (distance2 (a, b)); return std::sqrt (distance2 (a, b));
} }
//------------------------------------------------------------------------- //-------------------------------------------------------------------------
template <size_t S, typename T, typename U> template <size_t S, typename T, typename U>
constexpr typename std::common_type<T,U>::type constexpr typename std::common_type<T,U>::type
distance2 (point<S,T> a, point<S,U> b) util::distance2 (point<S,T> a, point<S,U> b)
{ {
typename std::common_type<T,U>::type sum {0}; typename std::common_type<T,U>::type sum {0};
for (size_t i = 0; i < S; ++i) for (size_t i = 0; i < S; ++i)
sum += pow2 (a.data[i] - b.data[i]); sum += pow2 (a.data[i] - b.data[i]);
return sum; return sum;
} }
//------------------------------------------------------------------------- //-------------------------------------------------------------------------
template <typename T, typename U> template <typename T, typename U>
typename std::common_type<T,U>::type typename std::common_type<T,U>::type
octile (point2<T> a, point2<U> b) util::octile (point2<T> a, point2<U> b)
{ {
using type_t = typename std::common_type<T,U>::type; using type_t = typename std::common_type<T,U>::type;
static_assert (!std::is_integral<type_t>::value, static_assert (!std::is_integral<type_t>::value,
"octile requires more than integer precision"); "octile requires more than integer precision");
const type_t D1 = 1; const type_t D1 = 1;
const type_t D2 = std::sqrt (type_t {2}); const type_t D2 = std::sqrt (type_t {2});
auto diff = util::abs (a - b); auto diff = util::abs (a - b);
// distance for axis-aligned walks // distance for axis-aligned walks
auto axis = D1 * (diff.x + diff.y); auto axis = D1 * (diff.x + diff.y);
// the savings from diagonal walks // the savings from diagonal walks
auto diag = (D2 - 2 * D1) * util::min (diff); auto diag = (D2 - 2 * D1) * util::min (diff);
return axis + diag; return axis + diag;
} }
//------------------------------------------------------------------------- //-------------------------------------------------------------------------
template <size_t S, typename T, typename U> template <size_t S, typename T, typename U>
constexpr typename std::common_type<T,U>::type constexpr typename std::common_type<T,U>::type
manhattan (point<S,T> a, point<S,U> b) util::manhattan (point<S,T> a, point<S,U> b)
{ {
typename std::common_type<T,U>::type sum {0}; typename std::common_type<T,U>::type sum {0};
for (size_t i = 0; i < S; ++i) for (size_t i = 0; i < S; ++i)
sum += util::abs (a.data[i] - b.data[i]); sum += util::abs (a.data[i] - b.data[i]);
return sum; return sum;
} }
//------------------------------------------------------------------------- //-------------------------------------------------------------------------
template <size_t S, typename T, typename U> template <size_t S, typename T, typename U>
constexpr typename std::common_type<T,U>::type constexpr typename std::common_type<T,U>::type
chebyshev(point<S,T> a, point<S,U> b) util::chebyshev(point<S,T> a, point<S,U> b)
{ {
return util::max (abs (a - b)); return util::max (abs (a - b));
}
} }