/*graficacion en 3d Perspectiva conica
  D              distancia del observador
  (x3d,y3d,z3d)  punto en 3d
  (x2d,y2d)      punto en 2d
   x2d=y3d*D/(D-z3d)
   y2d=x3d*D/(D-z3d)
  Fernando Galindo Soria 19/iv/98 Cd. de Mexico */
#include <graphics.h>
#include <math.h>
#include <conio.h>
#include <time.h>
#include <stdlib.h>
#include <stdio.h>
/*#include <dos.h>*/

void arbol(int,int,int,int,int,int);
int ind,w0,w1,w2;
float D=500,zlim=20,x2d,y2d,x2d1,y2d1,z3d;
float f3d[][3]={1,1,1, 2,1,1, 2,2,1, 1,2,1, 1,1,1,
		1,1,1.5, 2,1,1.5, 2,2,1.5, 1,2,1.5, 1,1,1.5,
		1,1,1, 2,1,1, 2,1,1.5, 2,2,1.5, 2,2,1, 1,2,1,
		1,2,1.5, 1,1,1.5, 1,1,1};

void main()
{ int z3;
  int gd=DETECT,gm;
  initgraph(&gd,&gm,"");
  randomize();
  ind=1;
  while(kbhit()==0){
    z3=random(zlim);
    setcolor(z3);
    w0=70+random(27); w1=95+random(37); w2=127+random(37);
    arbol(random(600),random(100),z3,40,90,0);
    }
  getch();
  closegraph();
}

void arbol(int x3,int y3,int z3,int l,int an,int an1)
{
  float x0,y0,x1,y1,x31,y31,z31;
  if(kbhit()==0)
  if (l > ind )
  {
  x0=x3*D/(D-z3);
  y0=y3*D/(D-z3);
  x31=x3-(l*cos(an/57.29578));
  y31=y3-(l*sin(an/57.29578));
  z31=z3-(l*tan(an1/57.29578));
  x1=x31*D/(D-z31);
  y1=y31*D/(D-z31);
//  printf("\n %d %d %d %d %d %d %d %d %d ",x3,y3,z3,l,an,x0,y0,x1,y1);
  line(x0,y0+326,x1,y1+326);
  arbol(x31,y31,z31,l/1.45,an-w0,an1+11);
  arbol(x31,y31,z31,l/1.45,an+w1,an1+7);
  arbol(x31,y31,z31,l/1.45,an+w2,an1-11);
  }
}