Jonathan Schleifer
fd09d38b8c
FossilOrigin-Name: 12cac9666ac09097e06d34da46bf50d15c8571dea22fd2a6d8a1fad076999689
90 lines
2.1 KiB
Objective-C
90 lines
2.1 KiB
Objective-C
// rndmap.cpp: perlin noise landscape generation and some experimental random
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// map stuff, currently not used
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#include "cube.h"
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float
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noise(int x, int y, int seed)
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{
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int n = x + y * 57;
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n = (n << 13) ^ n;
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return 1.0f -
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((n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff) /
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1073741824.0f;
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}
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float
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smoothednoise(int x, int y, int seed)
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{
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float corners =
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(noise(x - 1, y - 1, seed) + noise(x + 1, y - 1, seed) +
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noise(x - 1, y + 1, seed) + noise(x + 1, y + 1, seed)) /
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16;
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float sides = (noise(x - 1, y, seed) + noise(x + 1, y, seed) +
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noise(x, y - 1, seed) + noise(x, y + 1, seed)) /
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8;
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float center = noise(x, y, seed) / 4;
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return corners + sides + center;
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}
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float
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interpolate(float a, float b, float x)
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{
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float ft = x * 3.1415927f;
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float f = (1.0f - (float)cos(ft)) * 0.5f;
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return a * (1 - f) + b * f;
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}
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float
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interpolatednoise(float x, float y, int seed)
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{
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int ix = (int)x;
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float fx = x - ix;
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int iy = (int)y;
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float fy = y - iy;
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float v1 = smoothednoise(ix, iy, seed);
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float v2 = smoothednoise(ix + 1, iy, seed);
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float v3 = smoothednoise(ix, iy + 1, seed);
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float v4 = smoothednoise(ix + 1, iy + 1, seed);
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float i1 = interpolate(v1, v2, fx);
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float i2 = interpolate(v3, v4, fy);
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return interpolate(i1, i2, fy);
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}
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float
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perlinnoise_2D(float x, float y, int seedstep, float pers)
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{
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float total = 0;
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int seed = 0;
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for (int i = 0; i < 7; i++) {
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float frequency = (float)(2 ^ i);
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float amplitude = (float)pow(pers, i);
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total += interpolatednoise(x * frequency, y * frequency, seed) *
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amplitude;
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seed += seedstep;
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}
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return total;
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}
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void
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perlinarea(const struct block *b, int scale, int seed, int psize)
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{
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srand(seed);
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seed = rnd(10000);
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if (!scale)
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scale = 10;
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for (int x = b->x; x <= b->x + b->xs; x++) {
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for (int y = b->y; y <= b->y + b->ys; y++) {
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struct sqr *s = S(x, y);
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if (!SOLID(s) && x != b->x + b->xs && y != b->y + b->ys)
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s->type = FHF;
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s->vdelta =
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(int)(perlinnoise_2D(x / ((float)scale) + seed,
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y / ((float)scale) + seed, 1000, 0.01f) *
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50 +
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25);
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if (s->vdelta > 128)
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s->vdelta = 0;
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}
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}
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}
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