libcruft-util/noise/basis/value.ipp

92 lines
2.9 KiB
Plaintext
Raw Normal View History

/*
* 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 2012-2015 Danny Robson <danny@nerdcruft.net>
*/
#ifdef __UTIL_NOISE_BASIS_VALUE_IPP
#error
#endif
#define __UTIL_NOISE_BASIS_VALIE_IPP
#include "../rand.hpp"
2015-10-06 15:45:26 +11:00
#include "../../types.hpp"
namespace util { namespace noise { namespace basis {
///////////////////////////////////////////////////////////////////////////
template <size_t S, typename T, template <typename> class L>
2015-10-06 15:45:26 +11:00
value<S,T,L>::value (seed_t _seed):
2015-06-02 17:07:42 +10:00
m_seed (_seed)
{ ; }
//-------------------------------------------------------------------------
template <size_t S, typename T, template <typename> class L>
util::range<T>
2015-10-06 15:45:26 +11:00
value<S,T,L>::bounds (void) const
{
return { -1, 1 };
}
2015-06-02 17:07:42 +10:00
//-------------------------------------------------------------------------
template <size_t S, typename T, template <typename> class L>
seed_t
2015-10-06 15:45:26 +11:00
value<S,T,L>::seed (void) const
2015-06-02 17:07:42 +10:00
{
return m_seed;
}
//-------------------------------------------------------------------------
template <size_t S, typename T, template <typename> class L>
2015-06-02 17:07:42 +10:00
seed_t
2015-10-06 15:45:26 +11:00
value<S,T,L>::seed (seed_t _seed)
2015-06-02 17:07:42 +10:00
{
return m_seed = _seed;
}
//-------------------------------------------------------------------------
template <size_t S, typename T, template <typename> class L>
T
value<S,T,L>::operator() (util::point<S,T> p) const noexcept
{
// extract integer and fractional parts. be careful to always round down
auto p_int = floor (p).template cast<intmax_t> ();
2015-06-17 03:05:16 +10:00
auto p_rem = p - p_int;
// generate the corner points
2015-10-06 15:45:26 +11:00
std::array<pointi<S>,pow(2,S)> p_;
std::transform (std::begin (this->CORNERS), std::end (this->CORNERS),
std::begin (p_),
[p_int] (auto i) { return p_int + i; });
2015-10-06 15:45:26 +11:00
// Generate the corner values
std::array<T,pow(2,S)> g_;
std::transform (std::begin (p_), std::end (p_),
std::begin (g_),
[this] (auto i) { return rand::scalar<value_t> (m_seed, i) * 2 - 1; });
// Interpolate on one dimension, then the other.
2015-10-06 15:45:26 +11:00
T l_[pow(2,S)];
std::copy (std::begin (g_), std::end (g_), std::begin (l_));
2015-10-06 15:45:26 +11:00
for (size_t i = S; i; --i)
for (size_t j = 0; j < std::pow(2,i); j += 2)
l_[j / 2] = L<T>() (l_[j], l_[j+1], p_rem[S-i]);
2015-10-06 15:45:26 +11:00
return l_[0];
}
} } }