73 lines
2.5 KiB
C++
73 lines
2.5 KiB
C++
#include "Perlin.h"
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#include <cmath>
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#include <numeric>
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#include <random>
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#include <algorithm>
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namespace ZL {
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PerlinNoise::PerlinNoise() {
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p.resize(256);
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std::iota(p.begin(), p.end(), 0);
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// Ïåðåìåøèâàåì äëÿ ñëó÷àéíîñòè (ìîæíî çàäàòü seed)
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std::default_random_engine engine(77777);
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std::shuffle(p.begin(), p.end(), engine);
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p.insert(p.end(), p.begin(), p.end()); // Äóáëèðóåì äëÿ ïåðåïîëíåíèÿ
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}
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PerlinNoise::PerlinNoise(uint64_t seed) {
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p.resize(256);
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std::iota(p.begin(), p.end(), 0);
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// Ïåðåìåøèâàåì äëÿ ñëó÷àéíîñòè (èñïîëüçóåì ïåðåäàííûé seed)
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std::default_random_engine engine(static_cast<unsigned int>(seed));
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std::shuffle(p.begin(), p.end(), engine);
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p.insert(p.end(), p.begin(), p.end()); // Äóáëèðóåì äëÿ ïåðåïîëíåíèÿ
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}
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float PerlinNoise::fade(float t) { return t * t * t * (t * (t * 6 - 15) + 10); }
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float PerlinNoise::lerp(float t, float a, float b) { return a + t * (b - a); }
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float PerlinNoise::grad(int hash, float x, float y, float z) {
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int h = hash & 15;
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float u = h < 8 ? x : y;
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float v = h < 4 ? y : (h == 12 || h == 14 ? x : z);
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return ((h & 1) == 0 ? u : -u) + ((h & 2) == 0 ? v : -v);
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}
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float PerlinNoise::noise(float x, float y, float z) {
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int X = (int)floor(x) & 255;
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int Y = (int)floor(y) & 255;
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int Z = (int)floor(z) & 255;
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x -= floor(x);
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y -= floor(y);
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z -= floor(z);
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float u = fade(x);
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float v = fade(y);
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float w = fade(z);
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int A = p[X] + Y, AA = p[A] + Z, AB = p[A + 1] + Z;
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int B = p[X + 1] + Y, BA = p[B] + Z, BB = p[B + 1] + Z;
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return lerp(w, lerp(v, lerp(u, grad(p[AA], x, y, z), grad(p[BA], x - 1, y, z)),
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lerp(u, grad(p[AB], x, y - 1, z), grad(p[BB], x - 1, y - 1, z))),
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lerp(v, lerp(u, grad(p[AA + 1], x, y, z - 1), grad(p[BA + 1], x - 1, y, z - 1)),
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lerp(u, grad(p[AB + 1], x, y - 1, z - 1), grad(p[BB + 1], x - 1, y - 1, z - 1))));
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}
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float PerlinNoise::getSurfaceHeight(Vector3f pos, float noiseCoeff) {
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// ×àñòîòà øóìà (÷åì áîëüøå, òåì áîëüøå "õîëìîâ")
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float frequency = 7.0f;
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// Ïîëó÷àåì çíà÷åíèå øóìà (îáû÷íî îò -1 äî 1)
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float noiseValue = noise(pos.v[0] * frequency, pos.v[1] * frequency, pos.v[2] * frequency);
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// Ìàñøòàáèðóåì: õîòèì îòêëîíåíèå îò 1.0 äî 1.1 (ïðèìåðíî)
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float height = 1.0f + (noiseValue * noiseCoeff);
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return height;
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}
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} // namespace ZL
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