/*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 19/vii/2002 Cd. de Mexico 5
  www.fgalindosoria.com  fgalindo@ipn.mx  www.laredi.com*/
#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;
float D=80,zlim=20,x2d,y2d,x2d1,y2d1,z3d;
float f3d[][3]={10,10,10, 300,10,10, 300,50,50, 10,50,50, 10,10,10,
		50,300,15, 300,300,15, 300,300,15, 50,300,15, 50,300,15,
		50,300,10, 300,300,10, 300,300,15, 300,300,15, 300,300,10,
		50,300,10, 50,300,15, 50,300,15, 50,300,10};

void main()
{ int z3,i;
  int gd=DETECT,gm;
  initgraph(&gd,&gm,"");
  randomize();
  ind=1;
  while(kbhit()==0){
    setcolor(15);
    for (i=0;i<4;i++)
      line(f3d[i][0]*D/(D-f3d[i][2]),300+f3d[i][1]*D/(D-f3d[i][2]),f3d[i+1][0]*D/(D-f3d[i+1][2]),300+f3d[i+1][1]*D/(D-f3d[i+1][2]));
    z3=random(zlim);
    setcolor(z3);
    arbol(random(600),random(100),z3,40,90,0);
    if(random(10)==3){delay(500);cleardevice();}
    }
  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); delay(1);
  arbol(x31,y31,z31,l/1.7,an-47,an1+5);
  arbol(x31,y31,z31,l/1.7,an,an1+7);
  arbol(x31,y31,z31,l/1.7,an+47,an1-5);
  }
}