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