337 lines
9.7 KiB
C++
337 lines
9.7 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2012-2015 Danny Robson <danny@nerdcruft.net>
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*/
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#include "noise/basis.hpp"
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#include "noise/lut.hpp"
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#include "../debug.hpp"
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#include "../point.hpp"
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#include "../random.hpp"
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#include "../vector.hpp"
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#include "../hash/murmur/murmur2.hpp"
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#include <algorithm>
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using util::noise::basis;
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using util::noise::value;
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using util::noise::gradient;
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using util::noise::cellular;
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///////////////////////////////////////////////////////////////////////////////
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// Generate a type from [-UNIT..UNIT]
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template <typename T>
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T
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generate (intmax_t x, intmax_t y, uint64_t seed)
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{
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using util::hash::murmur2::mix;
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T v = mix (seed, mix (uint64_t (y), uint64_t (x))) & 0xffff;
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v = v / T{0xffff} * 2 - 1;
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CHECK_GE (v, T{0});
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CHECK_LE (v, T{1});
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return v;
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}
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//-----------------------------------------------------------------------------
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template <>
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util::vector2d
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generate (intmax_t x, intmax_t y, uint64_t seed)
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{
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using util::hash::murmur2::mix;
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auto u = mix (seed, mix (uint64_t (x), uint64_t (y)));
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auto v = mix (u, seed);
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auto r = util::vector2d {
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(u & 0xffff) / double{0xffff},
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(v & 0xffff) / double{0xffff}
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} * 2.0 - 1.0;
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CHECK_GE (r, double{-1});
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CHECK_LE (r, double{ 1});
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return r;
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}
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//-----------------------------------------------------------------------------
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template <>
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util::vector2f
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generate (intmax_t x, intmax_t y, uint64_t seed)
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{
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using util::hash::murmur2::mix;
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auto u = mix (seed, mix (uint64_t (x), uint64_t (y)));
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auto v = mix (u, seed);
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auto r = util::vector2f {
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(u & 0xffff) / float{0xffff},
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(v & 0xffff) / float{0xffff}
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} * 2.f - 1.f;
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CHECK_GE (r, float (-1));
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CHECK_LE (r, float ( 1));
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return r;
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}
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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basis<T>::basis (seed_t _seed):
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seed (_seed)
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{ ; }
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//-----------------------------------------------------------------------------
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template <typename T>
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basis<T>::basis ():
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seed (util::random<seed_t> ())
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{ ; }
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//-----------------------------------------------------------------------------
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template <typename T>
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basis<T>::~basis ()
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{ ; }
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//-----------------------------------------------------------------------------
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template <typename T>
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T
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basis<T>::operator() (T, T) const
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{
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unreachable ();
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}
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//-----------------------------------------------------------------------------
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namespace util { namespace noise {
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template struct basis<float>;
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template struct basis<double>;
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} }
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///////////////////////////////////////////////////////////////////////////////
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template <typename T, util::noise::lerp_t<T> L>
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value<T,L>::value (seed_t _seed):
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basis<T> (_seed)
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{ ; }
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//-----------------------------------------------------------------------------
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template <typename T, util::noise::lerp_t<T> L>
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value<T,L>::value ()
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{ ; }
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//-----------------------------------------------------------------------------
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template <typename T, util::noise::lerp_t<T> L>
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util::range<T>
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value<T,L>::bounds (void) const
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{
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return { -1, 1 };
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}
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//-----------------------------------------------------------------------------
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template <typename T, util::noise::lerp_t<T> L>
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T
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value<T,L>::operator() (T x, T y) const
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{
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intmax_t x_int = static_cast<intmax_t> (x);
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intmax_t y_int = static_cast<intmax_t> (y);
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T x_fac = x - x_int;
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T y_fac = y - y_int;
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// Shift the coordinate system down a little to ensure we get unit weights
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// for the lerp. It's better to do this than abs the fractional portion so
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// we don't get reflections along the origin.
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if (x < 0) { x_fac = 1 + x_fac; x_int -= 1; }
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if (y < 0) { y_fac = 1 + y_fac; y_int -= 1; }
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// Generate the four corner values
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T p0 = generate<T> (x_int, y_int, this->seed);
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T p1 = generate<T> (x_int + 1, y_int, this->seed);
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T p2 = generate<T> (x_int, y_int + 1, this->seed);
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T p3 = generate<T> (x_int + 1, y_int + 1, this->seed);
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// Interpolate on one dimension, then the other.
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return L (L (p0, p1, x_fac),
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L (p2, p3, x_fac),
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y_fac);
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}
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//-----------------------------------------------------------------------------
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namespace util { namespace noise {
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template struct value<float, lerp::linear>;
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template struct value<float, lerp::cubic>;
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template struct value<float, lerp::quintic>;
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template struct value<double, lerp::linear>;
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template struct value<double, lerp::cubic>;
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template struct value<double, lerp::quintic>;
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} }
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///////////////////////////////////////////////////////////////////////////////
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template <typename T, util::noise::lerp_t<T> L>
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gradient<T,L>::gradient (seed_t _seed):
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basis<T> (_seed)
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{ ; }
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//-----------------------------------------------------------------------------
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template <typename T, util::noise::lerp_t<T> L>
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gradient<T,L>::gradient ()
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{ ; }
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//-----------------------------------------------------------------------------
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template <typename T, util::noise::lerp_t<T> L>
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util::range<T>
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gradient<T,L>::bounds (void) const
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{ return { -std::sqrt(T{2}) / 2, std::sqrt (T{2}) / 2 }; }
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//-----------------------------------------------------------------------------
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template <typename T, util::noise::lerp_t<T> L>
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T
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gradient<T,L>::operator() (T x, T y) const
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{
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intmax_t x_int = static_cast<intmax_t> (x);
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intmax_t y_int = static_cast<intmax_t> (y);
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T x_fac = x - x_int;
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T y_fac = y - y_int;
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// Shift the coordinate system down a little to ensure we get unit weights
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// for the lerp. It's better to do this than abs the fractional portion so
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// we don't get reflections along the origin.
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if (x < 0) { x_fac = 1 + x_fac; x_int -= 1; }
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if (y < 0) { y_fac = 1 + y_fac; y_int -= 1; }
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// Generate the four corner values. It's not strictly necessary to
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// normalise the values, but we get a more consistent and visually
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// appealing range of outputs with normalised values.
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auto p0 = generate<vector<2,T>> (x_int, y_int, this->seed).normalise ();
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auto p1 = generate<vector<2,T>> (x_int + 1, y_int, this->seed).normalise ();
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auto p2 = generate<vector<2,T>> (x_int, y_int + 1, this->seed).normalise ();
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auto p3 = generate<vector<2,T>> (x_int + 1, y_int + 1, this->seed).normalise ();
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T v0 = p0.x * x_fac + p0.y * y_fac;
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T v1 = p1.x * (x_fac - 1) + p1.y * y_fac;
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T v2 = p2.x * x_fac + p2.y * (y_fac - 1);
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T v3 = p3.x * (x_fac - 1) + p3.y * (y_fac - 1);
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return L (L (v0, v1, x_fac),
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L (v2, v3, x_fac),
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y_fac);
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}
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//-----------------------------------------------------------------------------
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namespace util {
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namespace noise {
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template struct gradient<float, lerp::linear>;
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template struct gradient<float, lerp::cubic>;
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template struct gradient<float, lerp::quintic>;
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template struct gradient<double, lerp::linear>;
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template struct gradient<double, lerp::cubic>;
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template struct gradient<double, lerp::quintic>;
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}
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}
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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cellular<T>::cellular (seed_t _seed):
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basis<T> (_seed)
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{ ; }
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//-----------------------------------------------------------------------------
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template <typename T>
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cellular<T>::cellular ()
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{ ; }
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//-----------------------------------------------------------------------------
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template <typename T>
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util::range<T>
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cellular<T>::bounds (void) const
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{ return { 0.0, 1.5 }; }
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//-----------------------------------------------------------------------------
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template <typename T>
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T
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cellular<T>::operator() (T x, T y) const
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{
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intmax_t x_int = static_cast<intmax_t> (x);
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intmax_t y_int = static_cast<intmax_t> (y);
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T x_fac = x - x_int;
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T y_fac = y - y_int;
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// Generate the four corner values. It's not strictly necessary to
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// normalise the values, but we get a more consistent and visually
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// appealing range of outputs with normalised values.
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if (x < 0) { x_fac = 1 + x_fac; x_int -= 1; }
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if (y < 0) { y_fac = 1 + y_fac; y_int -= 1; }
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// +---+---+---+
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// | 0 | 1 | 2 |
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// +---+---+---+
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// | 3 | 4 | 5 |
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// +---+-------+
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// | 6 | 7 | 8 |
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// +---+---+---+
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point<2,T> centre = { x_fac, y_fac };
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T distances[9] = { std::numeric_limits<T>::quiet_NaN () };
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T *cursor = distances;
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for (signed y_off = -1; y_off <= 1 ; ++y_off)
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for (signed x_off = -1; x_off <= 1; ++x_off) {
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auto pos = point<2,T> (T (x_off), T (y_off));
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auto off = generate<vector<2,T>> (x_int + x_off, y_int + y_off, this->seed);
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off += T{1};
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off /= T{2};
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CHECK (off.x >= 0 && off.x <= 1);
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CHECK (off.y >= 0 && off.y <= 1);
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pos += off;
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*cursor++ = pos.distance2 (centre);
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}
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std::sort (std::begin (distances), std::end (distances));
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CHECK_GE (distances[0], 0);
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CHECK (bounds ().contains (distances[0]));
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return distances[0];
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}
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//-----------------------------------------------------------------------------
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namespace util { namespace noise {
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template struct cellular<float>;
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template struct cellular<double>;
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} }
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