nerdcruft/libcruft-util
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noise-tool: offset heights to ensure landmass

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This commit is contained in:
Danny Robson 2015-06-04 15:13:58 +10:00
parent 53917404b4
commit 851f7b9351
1 changed files with 32 additions and 0 deletions
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32
tools/noise.cpp
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@ -76,6 +76,36 @@ write_map (const util::image::buffer<float> &map, boost::filesystem::path name)
} }
void
adjust_ocean (util::image::buffer<float> &height,
const float percentage = .2f)
{
static const float WATER_HEIGHT = 0.5f;
CHECK_LIMIT (percentage, 0, 1);
// we assume fully packed data for iteration purposes
CHECK (height.is_packed ());
std::array<unsigned,256> buckets{ 0 };
for (const auto h: height)
buckets[h * 255]++;
size_t pivot = 0;
for (size_t accum = 0, target = percentage * height.area (); pivot < buckets.size (); ++pivot) {
accum += buckets[pivot];
if (accum > target)
break;
}
std::cerr << "pivot: " << pivot << '\n';
float offset = WATER_HEIGHT - pivot / 256.f;
for (auto &h: height)
h += offset;
}
int int
main (void) main (void)
{ {
@ -137,6 +167,8 @@ main (void)
std::transform (img.begin (), img.end (), img.begin (), [offset,div] (auto i) { return (i - offset) / div; }); std::transform (img.begin (), img.end (), img.begin (), [offset,div] (auto i) { return (i - offset) / div; });
// ensure the ocean isn't too big
adjust_ocean (img, 0.2f);
// write the images to disk // write the images to disk
write_map (img, "noise"); write_map (img, "noise");