Miscellany

#include <stdio.h>#include <math.h>#include <stdlib.h>#include <time.h>#define PI 3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825#define PI2 (PI*2)#define SQ2 1.414213562373095048801688724209698078569671875376948073176679737990732478462#define FI 1.618033988749894848204586834365638117720309179805762862135448622705260462818902449707207204#define SX 666#define SY 666#define NPT 100#define RSD 666#define V3D 0/*#define SX 666#define SY 666#define NPT 1000#define RSD 1923879#define V3D 1*/#define BPL ((SX*3+3)&~3)void seedr(unsigned int);unsigned int rnd();unsigned int rndm(unsigned int);unsigned char bhdr[54]={0x42, 0x4D, 0x36, 0x00, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x36, 0x00, 0x00, 0x00, 0x28, 0x00,0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x01, 0x00, 0x18, 0x00, 0x00, 0x00,0x00, 0x00, 0x00, 0x00, 0x30, 0x00, 0x12, 0x0B, 0x00, 0x00, 0x12, 0x0B, 0x00, 0x00, 0x00, 0x00,0x00, 0x00, 0x00, 0x00, 0x00, 0x00};unsigned char po[BPL];double gr[SY][SX][3];void drawit();int main(int a, char **b) {  FILE *o;  int x, y, c;  double t;  unsigned char *p;  srand(time(0));  drawit();    p=bhdr+2; *p++=x=54+BPL*SY; *p++=x>>=8; *p++=x>>=8; *p=x>>=8;  p=bhdr+18; *p++=x=SX; *p++=x>>=8; *p++=x>>=8; *p++=x>>=8;  *p++=x=SY; *p++=x>>=8; *p++=x>>=8; *p=x>>=8;  if(!(o=fopen("voronoi.bmp", "wb"))) {    fclose(o);    printf("Couldn't open output file.\n");    return(0);  }    fwrite(bhdr, 54, 1, o);  for(x=SX*3;x<BPL;++x) po[x]=0;    for(y=SY-1;~y;--y) {    for(x=0,p=po;x<SX;++x) for(c=2;~c;--c) *p++=(t=gr[y][x][c])<=0?0:(t>=1?255:t*255);    fwrite(po, BPL, 1, o);  }  fclose(o);  return(0);}int ptx[NPT], pty[NPT], ptz[NPT];double ptc[NPT][3];void drawit() {  int x, y, c, n, bn, dx, dy, dz;  unsigned int m, p;  seedr(RSD);  for(n=0;n<NPT;++n) {    ptx[n]=rndm(SX); pty[n]=rndm(SX); ptz[n]=(!!V3D)*(rndm(SX)-SX/2);    for(c=0;c<3;++c) ptc[n][c]=rnd()/(double)~0u;  }  for(y=0;y<SY;++y) for(x=0;x<SY;++x) {    for(n=0,m=~0;n<NPT;++n) {      dx=x-ptx[n]; dy=y-pty[n]; dz=-ptz[n]; p=dx*dx+dy*dy+dz*dz;      if(p<m) { m=p; bn=n; }    }    for(c=0;c<3;++c) gr[y][x][c]=ptc[bn][c];  }  if(!V3D)    for(n=0;n<NPT;++n)      for(y=-1+!pty[n];y<=1-(pty[n]==SY-1);++y)        for(x=-1+!ptx[n];x<=1-(ptx[n]==SX-1);++x)          for(c=0;c<3;++c)            gr[pty[n]+y][ptx[n]+x][c]=0;}unsigned int rseeda[624];int rseedu;void seedr(unsigned int s) {  int n;  rseedu=624; rseeda[0]=s; for(n=1;n<624;++n) rseeda[n]=s*=69069u;}#define TEMPBLAH(x,y,z) { v=(rseeda[x]&0x80000000)|(rseeda[y]&0x7fffffff);\                          rseeda[x]=rseeda[z]^(v>>1)^(0x9908b0df&(0-(v&1)));}void gennewr() {  int n;  unsigned int v;  for(n=0;n<227;++n) TEMPBLAH(n, n+1, n+397);  for(;n<623;++n) TEMPBLAH(n, n+1, n-227);  TEMPBLAH(623, 0, 396);  rseedu=0;}#undef TEMPBLAHunsigned int rnd() {  if(rseedu>=624) gennewr();  unsigned int v=rseeda[rseedu++];  v^=v>>11;  v^=(v<<7)&0x9d2c5680;  v^=(v<<15)&0xefc60000;  v^=v>>18;  return(v);}unsigned int rndm(unsigned int m) {  unsigned int v, c=(0u-m)/m;  while((v=rnd())/m>c);  return(v%m);}//