81 lines
2.7 KiB
C++
81 lines
2.7 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 2012-2015 Danny Robson <danny@nerdcruft.net>
|
|
*/
|
|
|
|
#ifdef __UTIL_NOISE_BASIS_PERLIN_IPP
|
|
#error
|
|
#endif
|
|
#define __UTIL_NOISE_BASIS_PERLIN_IPP
|
|
|
|
#include "../../types.hpp"
|
|
|
|
|
|
namespace util { namespace noise { namespace basis {
|
|
///////////////////////////////////////////////////////////////////////////
|
|
template <size_t S, typename T, template <typename> class L, template <size_t,typename> class G>
|
|
perlin<S,T,L,G>::perlin (seed_t _seed):
|
|
G<S,T> (_seed)
|
|
{ ; }
|
|
|
|
|
|
//-------------------------------------------------------------------------
|
|
template <size_t S, typename T, template <typename> class L, template <size_t,typename> class G>
|
|
util::range<T>
|
|
perlin<S,T,L,G>::bounds (void) const
|
|
{
|
|
return {
|
|
-std::sqrt (T{2}) / 2,
|
|
std::sqrt (T{2}) / 2
|
|
};
|
|
}
|
|
|
|
|
|
//-------------------------------------------------------------------------
|
|
template <size_t S, typename T, template <typename> class L, template <size_t,typename> class G>
|
|
T
|
|
perlin<S,T,L,G>::operator() (point_t p) const noexcept
|
|
{
|
|
// extract integer and fractional parts. be careful to always round down
|
|
auto p_int = floor (p).template cast<intmax_t> ();
|
|
auto p_rem = p - p_int;
|
|
|
|
// generate the corner positions
|
|
pointi<S> p_[pow(2,S)];
|
|
std::transform (std::begin (this->CORNERS), std::end (this->CORNERS),
|
|
std::begin (p_),
|
|
[p_int] (auto i) { return i + p_int; });
|
|
|
|
// generate the corner gradients
|
|
vector<S,T> g_[pow(2,S)];
|
|
std::transform (std::begin (p_), std::end (p_),
|
|
std::begin (g_),
|
|
[this] (auto i) { return this->generate (i); });
|
|
|
|
// compute the dot products
|
|
T v_[pow(2,S)];
|
|
for (size_t i = 0; i < elems (v_); ++i)
|
|
v_[i] = dot (g_[i], p - p_[i]);
|
|
|
|
// interpolate the results
|
|
T l_[pow(2,S)];
|
|
std::copy (std::begin (v_), std::end (v_), std::begin (l_));
|
|
|
|
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]);
|
|
return l_[0];
|
|
}
|
|
} } }
|