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Merge perlin parameter class updates

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This commit is contained in:
Danny Robson 2012-04-11 15:25:10 +10:00
parent 043ee6d31e
commit 5f6504de73
2 changed files with 75 additions and 19 deletions
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93
perlin.cpp
View File

@ -1,27 +1,76 @@
#include "perlin.hpp"
#include "lerp.hpp"
#include "bitwise.hpp"
#include "debug.hpp"
#include "hash.hpp"
#include "lerp.hpp"
#include "maths.hpp"
#include "random.hpp"
#include <cmath>
#include <limits>
struct params {
typedef size_t seed_t;
unsigned octaves;
double persistence;
seed_t seed;
double
generate (intmax_t x, intmax_t y) {
intmax_t mixed = rotate_left (x, sizeof (x) * 4) | y;
seed_t key = (seed_t)mixed ^ seed;
return util::hash (key) / (double)std::numeric_limits<intmax_t>::max ();
}
double
smooth2d (intmax_t x, intmax_t y) {
double corners = (generate(x - 1, y - 1) +
generate(x + 1, y - 1) +
generate(x - 1, y + 1) +
generate(x + 1, y + 1)) / 16.0;
double sides = (generate(x - 1, y ) +
generate(x + 1, y ) +
generate(x, y - 1) +
generate(x, y + 1)) / 8.0;
double center = generate(x, y ) / 4.0;
return corners + sides + center;
}
params ():
octaves (16),
persistence (0.7),
seed (util::random<size_t> ())
{ ; }
};
// Just a random generator [-1.0, 1.0]
static float
generate (intmax_t x, intmax_t y) {
uint32_t n = x + 257 * y;
n = (n << 13U) ^ n;
generate (intmax_t x, intmax_t y, size_t seed) {
intmax_t n = x + 257 * y;
n = (n << 13U) ^ n ^ seed;
return (1.0 - ((n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0f);
}
double
smooth2d (intmax_t x, intmax_t y) {
double corners = (generate(x-1, y-1)+generate(x+1, y-1)+generate(x-1, y+1)+generate(x+1, y+1) ) / 16.0;
double sides = (generate(x-1, y) +generate(x+1, y) +generate(x, y-1) +generate(x, y+1) ) / 8.0;
double center = generate(x, y) / 4.0;
smooth2d (intmax_t x, intmax_t y, size_t seed) {
double corners = (generate(x - 1, y - 1, seed) +
generate(x + 1, y - 1, seed) +
generate(x - 1, y + 1, seed) +
generate(x + 1, y + 1, seed)) / 16.0;
double sides = (generate(x - 1, y, seed) +
generate(x + 1, y, seed) +
generate(x, y - 1, seed) +
generate(x, y + 1, seed)) / 8.0;
double center = generate(x, y, seed) / 4.0;
return corners + sides + center;
}
@ -34,16 +83,16 @@ curve (double t) {
double
sample2d (double x, double y) {
sample2d (double x, double y, size_t seed) {
intmax_t x_int = intmax_t (x);
double x_fac = x - x_int;
intmax_t y_int = intmax_t (y);
double y_fac = y - y_int;
double p0 = smooth2d (x_int, y_int);
double p1 = smooth2d (x_int + 1, y_int);
double p2 = smooth2d (x_int, y_int + 1);
double p3 = smooth2d (x_int + 1, y_int + 1);
double p0 = smooth2d (x_int, y_int, seed);
double p1 = smooth2d (x_int + 1, y_int, seed);
double p2 = smooth2d (x_int, y_int + 1, seed);
double p3 = smooth2d (x_int + 1, y_int + 1, seed);
double i0 = lerp::cosine (p0, p1, curve (x_fac));
double i1 = lerp::cosine (p2, p3, curve (x_fac));
@ -60,16 +109,16 @@ sigmoid (double x) {
double
perlin2d (double x, double y) {
size_t levels = 16;
perlin2d (double x, double y, size_t seed) {
size_t levels = 16;
double persistence = 0.7;
double total = 0.0;
double total = 0.0;
for (size_t i = 0; i < levels; ++i) {
double frequency = powf (2.0, i);
double amplitude = powf (persistence, i);
total += sample2d (x * frequency, y * frequency) * amplitude;
total += sample2d (x * frequency, y * frequency, seed) * amplitude;
}
return sigmoid (1.0 + total);
@ -77,11 +126,17 @@ perlin2d (double x, double y) {
void
perlin2d (uint8_t *restrict pixels, size_t width, size_t height) {
perlin2d (uint8_t *restrict pixels, size_t width, size_t height, const params& p) {
for (size_t y = 0; y < height; ++y)
for (size_t x = 0; x < width; ++x) {
double p = perlin2d (x / 10.0, y / 10.0);
double p = perlin2d (x / 10.0, y / 10.0, (size_t)pixels);
pixels[x + y * width] = p * std::numeric_limits<uint8_t>::max ();
}
}
void
perlin2d (uint8_t *restrict pixels, size_t width, size_t height) {
perlin2d (pixels, width, height, params ());
}

1
perlin.hpp
View File

@ -23,6 +23,7 @@
#include <cstdint>
#include <cstdlib>
void perlin2d (uint8_t *restrict pixels, size_t width, size_t height);
#endif