nerdcruft/libcruft-util
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Add cellular noise implementation

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This commit is contained in:
Danny Robson 2012-05-23 20:31:59 +10:00
parent 3885e9a9ab
commit 124878fc98
2 changed files with 59 additions and 4 deletions
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61
noise/basis.cpp
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@ -19,9 +19,13 @@
#include "noise/basis.hpp"
#include "noise/lut.hpp"
#include "../vector.hpp"
#include "../point.hpp"
#include "../random.hpp"
#include <algorithm>
using namespace util::noise;
///////////////////////////////////////////////////////////////////////////////
@ -85,9 +89,9 @@ template <lerp_function L>
template <lerp_function L>
double
value<L>::eval (double x, double y) const {
intmax_t x_int = intmax_t (x);
intmax_t x_int = static_cast<intmax_t> (x);
intmax_t y_int = static_cast<intmax_t> (y);
double x_fac = x - x_int;
intmax_t y_int = intmax_t (y);
double y_fac = y - y_int;
// Generate the four corner values
@ -121,9 +125,9 @@ gradient<L>::gradient ()
template <lerp_function L>
double
gradient<L>::eval (double x, double y) const {
intmax_t x_int = intmax_t (x);
intmax_t x_int = static_cast<intmax_t> (x);
intmax_t y_int = static_cast<intmax_t> (y);
double x_fac = x - x_int;
intmax_t y_int = intmax_t (y);
double y_fac = y - y_int;
// Generate the four corner values
@ -146,3 +150,52 @@ template struct gradient<lerp::linear>;
template struct gradient<lerp::cubic>;
template struct gradient<lerp::quintic>;
///////////////////////////////////////////////////////////////////////////////
cellular::cellular (seed_t _seed):
basis (_seed)
{ ; }
cellular::cellular ()
{ ; }
double
cellular::eval (double x, double y) const {
using util::point2;
intmax_t x_int = static_cast<intmax_t> (x);
intmax_t y_int = static_cast<intmax_t> (y);
double x_fac = x - x_int;
double y_fac = y - y_int;
// +---+---+---+
// | 0 | 1 | 2 |
// +---+---+---+
// | 3 | 4 | 5 |
// +---+-------+
// | 6 | 7 | 8 |
// +---+---+---+
point2 centre = { x_fac, y_fac };
double distances[9] = { std::numeric_limits<double>::quiet_NaN () };
double *cursor = distances;
for (signed y_off = -1; y_off <= 1 ; ++y_off)
for (signed x_off = -1; x_off <= 1; ++x_off) {
auto pos = point2 (double (x_off), double (y_off));
auto off = generate<vector2> (x_int + x_off, y_int + y_off, this->seed);
off += 1;
off /= 2;
CHECK (off.x >= 0 && off.x <= 1.0);
CHECK (off.y >= 0 && off.y <= 1.0);
pos += off;
*cursor++ = pos.distance2 (centre);
}
std::sort (std::begin (distances), std::end (distances));
return distances[0];
}

2
noise/fractal.cpp
View File

@ -72,6 +72,7 @@ util::noise::fbm<B>::eval (double x, double y) const {
}
template struct util::noise::fbm<util::noise::cellular>;
template struct util::noise::fbm<util::noise::gradient<lerp::linear>>;
template struct util::noise::fbm<util::noise::gradient<lerp::quintic>>;
template struct util::noise::fbm<util::noise::value<lerp::linear>>;
@ -123,6 +124,7 @@ util::noise::musgrave<B>::eval (double x, double y) const {
return total;
}
template struct util::noise::musgrave<util::noise::cellular>;
template struct util::noise::musgrave<util::noise::gradient<lerp::linear>>;
template struct util::noise::musgrave<util::noise::gradient<lerp::quintic>>;
template struct util::noise::musgrave<util::noise::value<lerp::linear>>;