n/midpoint: extract midpoint displacement funcs
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@ -170,6 +170,8 @@ UTIL_FILES = \
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noise/lerp.hpp \
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noise/lut.cpp \
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noise/lut.hpp \
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noise/midpoint.cpp \
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noise/midpoint.hpp \
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noise/turbulence.hpp \
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noise/turbulence.ipp \
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pascal.cpp \
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132
noise/midpoint.cpp
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132
noise/midpoint.cpp
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@ -0,0 +1,132 @@
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/*
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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 2015 Danny Robson <danny@nerdcruft.net>
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*/
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#include "midpoint.hpp"
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#include "region.hpp"
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#include "point.hpp"
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#include "hash/murmur/murmur2.hpp"
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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static T
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gen (uint64_t seed, util::point2u p)
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{
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using util::hash::murmur2::mix;
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uint64_t v = mix (
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seed,
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mix (
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p.y,
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p.x
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)
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) & 0xffff;
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return v / T{0xffff} * 2 - 1;
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}
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///////////////////////////////////////////////////////////////////////////////
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// assumes corner points have been assigned their weights
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template <typename T>
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static void
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fill (util::image::buffer<T> &img,
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uint64_t seed,
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util::region2u target,
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float scale,
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float persistence,
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float sides)
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{
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CHECK_EQ (target.e.w % 2, 1);
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CHECK_EQ (target.e.h % 2, 1);
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CHECK_GE (target.area (), 9);
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CHECK_GT (scale, 0);
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CHECK_GT (persistence, 0);
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CHECK_GE (sides, 0);
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const auto w = target.w;
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const auto h = target.h;
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// 0--1
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// | |
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// 2--3
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const auto p0 = target.p + util::vector2u {0, 0 };
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const auto p1 = target.p + util::vector2u {w-1, 0 };
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const auto p2 = target.p + util::vector2u {0, h-1};
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const auto p3 = target.p + util::vector2u {w-1, h-1};
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const auto v0 = img[p0];
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const auto v1 = img[p1];
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const auto v2 = img[p2];
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const auto v3 = img[p3];
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// do the centre
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{
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const auto avg = (v0 + v1 + v2 + v3) / 4;
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const auto val = avg + scale * gen<T> (seed, target.centre ());
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const auto pos = target.p + target.e / 2;
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img[pos] = val;
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}
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// average the sides
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{
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const auto p01 = target.p + util::vector2u{w/2, 0};
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const auto p13 = target.p + util::vector2u{w-1, h/2};
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const auto p32 = target.p + util::vector2u{w/2, h-1};
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const auto p20 = target.p + util::vector2u{0, h/2};
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const auto v01 = (v0 + v1) / 2 + sides * scale * gen<T> (seed, p01);
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const auto v13 = (v1 + v3) / 2 + sides * scale * gen<T> (seed, p13);
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const auto v32 = (v3 + v2) / 2 + sides * scale * gen<T> (seed, p32);
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const auto v20 = (v2 + v0) / 2 + sides * scale * gen<T> (seed, p20);
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img[p01] = v01;
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img[p13] = v13;
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img[p32] = v32;
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img[p20] = v20;
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}
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// recurse
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if (target.area () > 9) {
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auto e = target.e / 2 + 1;
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fill (img, seed, {target.p + util::vector2u{ 0, 0 }, e}, scale * persistence, persistence, sides);
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fill (img, seed, {target.p + util::vector2u{ w/2, 0 }, e}, scale * persistence, persistence, sides);
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fill (img, seed, {target.p + util::vector2u{ 0, h/2 }, e}, scale * persistence, persistence, sides);
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fill (img, seed, {target.p + util::vector2u{ w/2, h/2 }, e}, scale * persistence, persistence, sides);
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}
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}
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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void
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util::noise::midpoint (image::buffer<T> &img, uint64_t seed, float persistence, float sides)
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{
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img[{0, 0}] = gen<T> (seed, { 0, 0 });
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img[{0, img.w-1}] = gen<T> (seed, { 0, img.w-1 });
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img[{img.h-1, 0}] = gen<T> (seed, { img.h-1, 0 });
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img[{img.h-1, img.w-1}] = gen<T> (seed, { img.h-1, img.w-1 });
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fill (img, seed, { { 0, 0 }, img.extent () }, 1.f, persistence, sides);
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}
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//-----------------------------------------------------------------------------
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template void util::noise::midpoint (image::buffer<float>&, uint64_t, float, float);
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30
noise/midpoint.hpp
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30
noise/midpoint.hpp
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@ -0,0 +1,30 @@
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/*
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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 2015 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef __UTIL_NOISE_MIDPOINT_HPP
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#define __UTIL_NOISE_MIDPOINT_HPP
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#include "image.hpp"
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namespace util { namespace noise {
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template <typename T>
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void
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midpoint (image::buffer<T>&, uint64_t seed, float persistence = 0.65f, float sides = 0.25f);
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} }
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#include "midpoint.ipp"
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#endif
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124
tools/noise.cpp
124
tools/noise.cpp
@ -13,15 +13,14 @@
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#include "noise/basis/worley.hpp"
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#include "noise/turbulence.hpp"
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#include "noise/basis/runtime.hpp"
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#include "noise/midpoint.hpp"
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#include "extent.hpp"
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#include "colour.hpp"
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#include "netpbm.hpp"
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#include "types.hpp"
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#include "cmdopt.hpp"
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#include "hash/murmur/murmur2.hpp"
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#include "region.hpp"
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#include "random.hpp"
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///////////////////////////////////////////////////////////////////////////////
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@ -157,120 +156,29 @@ operator<< (std::ostream &os, lerp_t &l)
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}
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void
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diamond (util::image::buffer<float> &img, util::region2u target, float scale, float persistence)
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{
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}
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static float
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gen (uint64_t seed, util::point2u p)
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{
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using util::hash::murmur2::mix;
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uint64_t v = mix (
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seed,
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mix (
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p.y,
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p.x
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)
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) & 0xffff;
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return v / float{0xffff} * 2 - 1;
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}
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// perturb the centre point by at most scale-units
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// average the side points (optionally perturb by sides-units)
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//
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void
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midpoint (util::image::buffer<float> &img, uint64_t seed, util::region2u target, float scale, float persistence, float sides = 0.f)
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{
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CHECK_EQ (target.e.w % 2, 1);
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CHECK_EQ (target.e.h % 2, 1);
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CHECK_GE (target.area (), 9);
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CHECK_GT (scale, 0);
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CHECK_GT (persistence, 0);
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CHECK_GE (sides, 0);
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auto w = target.w;
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auto h = target.h;
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// 0--1
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// | |
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// 2--3
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auto p0 = target.p+util::vector2u{0, 0 };
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auto p1 = target.p+util::vector2u{w-1,0 };
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auto p2 = target.p+util::vector2u{0, h-1};
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auto p3 = target.p+util::vector2u{w-1,h-1};
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auto v0 = img[p0];
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auto v1 = img[p1];
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auto v2 = img[p2];
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auto v3 = img[p3];
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// do the centre
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auto avg = (v0 + v1 + v2 + v3) / 4;
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auto val = avg + scale * gen (seed, target.centre ());
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auto pos = target.p + target.e / 2;
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img[pos] = val;
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// average the sides
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auto p01 = target.p + util::vector2u{w/2, 0};
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auto p13 = target.p + util::vector2u{w-1, h/2};
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auto p32 = target.p + util::vector2u{w/2, h-1};
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auto p20 = target.p + util::vector2u{0, h/2};
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auto v01 = (v0 + v1) / 2 + sides * scale * gen (seed, p01);
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auto v13 = (v1 + v3) / 2 + sides * scale * gen (seed, p13);
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auto v32 = (v3 + v2) / 2 + sides * scale * gen (seed, p32);
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auto v20 = (v2 + v0) / 2 + sides * scale * gen (seed, p20);
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img[p01] = v01;
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img[p13] = v13;
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img[p32] = v32;
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img[p20] = v20;
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// recurse
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if (target.area () > 9) {
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auto e = target.e / 2 + 1;
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midpoint (img, seed, {target.p + util::vector2u{ 0, 0 }, e}, scale * persistence, persistence, sides);
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midpoint (img, seed, {target.p + util::vector2u{ w/2, 0 }, e}, scale * persistence, persistence, sides);
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midpoint (img, seed, {target.p + util::vector2u{ 0, h/2 }, e}, scale * persistence, persistence, sides);
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midpoint (img, seed, {target.p + util::vector2u{ w/2, h/2 }, e}, scale * persistence, persistence, sides);
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}
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}
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///////////////////////////////////////////////////////////////////////////////
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int
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main (int argc, char **argv)
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{
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//{
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// util::extent2u size { 1025 };
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// util::image::buffer<float> img (size);
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#if 0
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{
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srand (time (nullptr));
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// img[{0, 0}] = 0.7f;
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// img[{0, size.w-1}] = 0.1f;
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// img[{size.h-1, 0}] = 0.5f;
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// img[{size.h-1, size.w-1}] = 0.2f;
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// midpoint (img, { {0, 0}, size }, 1, 0.65f);
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util::extent2u size { 1025 };
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util::image::buffer<float> img (size);
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util::noise::midpoint (img, time (nullptr));
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// auto range = std::minmax_element (img.begin (), img.end ());
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// auto offset = *range.first;
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// auto div = *range.second - *range.first;
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// std::cerr << "range: [" << *range.first << ", " << *range.second << "]\n";
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auto range = std::minmax_element (img.begin (), img.end ());
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auto offset = *range.first;
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auto div = *range.second - *range.first;
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std::cerr << "range: [" << *range.first << ", " << *range.second << "]\n";
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// std::transform (img.begin (), img.end (), img.begin (), [offset,div] (auto i) { return (i - offset) / div; });
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// util::pgm::write (img.cast<uint8_t> (), std::cout);
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//}
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std::transform (img.begin (), img.end (), img.begin (), [offset,div] (auto i) { return (i - offset) / div; });
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util::pgm::write (img.cast<uint8_t> (), std::cout);
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}
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//return 0;
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return 0;
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#endif
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#ifndef ENABLE_DEBUGGING
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