nerdcruft/libcruft-util
1
0
Fork 0
Code Issues Releases Activity

noise-tool: stub midpoint/diamond noise functions

Browse Source
This commit is contained in:
Danny Robson 2015-06-30 22:23:57 +10:00
parent 72e7c60c4e
commit 1211ee0876
1 changed files with 79 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

79
tools/noise.cpp
View File

@ -19,6 +19,9 @@
#include "types.hpp"
#include "cmdopt.hpp"
#include "region.hpp"
#include "random.hpp"
///////////////////////////////////////////////////////////////////////////////
template struct util::noise::fractal::fbm<float, util::noise::basis::perlin<float,util::lerp::cubic>>;
@ -153,10 +156,86 @@ operator<< (std::ostream &os, lerp_t &l)
}
void
diamond (util::image::buffer<float> &img, util::region2u target, float scale, float persistence)
{
}
void
midpoint (util::image::buffer<float> &img, util::region2u target, float scale, float persistence)
{
CHECK_GE (target.area (), 9);
auto w = target.w;
auto h = target.h;
// 0--1
// | |
// 2--3
auto v0 = img[target.p+util::vector2u{0, 0 }];
auto v1 = img[target.p+util::vector2u{w-1,0 }];
auto v2 = img[target.p+util::vector2u{0, h-1}];
auto v3 = img[target.p+util::vector2u{w-1,h-1}];
// do the centre
auto avg = (v0 + v1 + v2 + v3) / 4;
auto val = avg + scale * (util::random<float> () * 2 - 1);
auto pos = target.p + target.e / 2;
img[pos] = val;
// average the sides
auto p01 = target.p + util::vector2u{w/2, 0};
auto p13 = target.p + util::vector2u{w-1, h/2};
auto p32 = target.p + util::vector2u{w/2, h -1};
auto p20 = target.p + util::vector2u{0, h/2};
img[p01] = (v0 + v1) / 2;
img[p13] = (v1 + v3) / 2;
img[p32] = (v3 + v2) / 2;
img[p20] = (v2 + v0) / 2;
// recurse
if (target.area () > 9) {
auto e = target.e / 2 + 1;
midpoint (img, {target.p + util::vector2u{ 0, 0 }, e}, scale * persistence, persistence);
midpoint (img, {target.p + util::vector2u{ w/2, 0 }, e}, scale * persistence, persistence);
midpoint (img, {target.p + util::vector2u{ 0, h/2 }, e}, scale * persistence, persistence);
midpoint (img, {target.p + util::vector2u{ w/2, h/2 }, e}, scale * persistence, persistence);
}
}
///////////////////////////////////////////////////////////////////////////////
int
main (int argc, char **argv)
{
//{
// util::extent2u size { 1025 };
// util::image::buffer<float> img (size);
// img[{0, 0}] = 0.7f;
// img[{0, size.w-1}] = 0.1f;
// img[{size.h-1, 0}] = 0.5f;
// img[{size.h-1, size.w-1}] = 0.2f;
// midpoint (img, { {0, 0}, size }, 1, 0.65f);
// auto range = std::minmax_element (img.begin (), img.end ());
// auto offset = *range.first;
// auto div = *range.second - *range.first;
// std::cerr << "range: [" << *range.first << ", " << *range.second << "]\n";
// std::transform (img.begin (), img.end (), img.begin (), [offset,div] (auto i) { return (i - offset) / div; });
// util::pgm::write (img.cast<uint8_t> (), std::cout);
//}
//return 0;
#ifndef ENABLE_DEBUGGING
if (isatty (fileno (stdout))) {
std::cerr << "cowardly refusing to dump binary data to console\n";