Rat's Nest 1/ratsnest1.iso/prgmming/c/disks.cpp

C/C++ Source or Header | 1996-02-19 | 5.2 KB | 136 lines

//

//+----------------------------------------------------------------------+

//+ Program DISKS.CPP                                                    +

//+ By Fausto A. A. Barbuto, [e-mail]               +

//+ Rio de Janeiro, BRAZIL, on May 14, 1994.                             +

//+                                                                      +

//+ Plots six Julia sets with inner contours in shadings of gray.        +

//+                                                                      +

//+ REFERENCE: Peitgen, H.-O. & Richter, P.H.: "The Beauty of Fractals", +

//+            Springer-Verlag, 1986.                                    +

//+                                                                      +

//+ Needs SVGA256.BGI and SVGA256.H (from SVGABG50 package by Jordan     +

//+ Hargrave).                                                           +

//+                                                                      +

//+ Authorized version for spanky.triumf.ca site (Vancouver, BC, CANADA).+

//+----------------------------------------------------------------------+

//

#include <stdio.h>

#include <conio.h>

#include <graphics.h>

#include <math.h>

#include "Svga256.h"

//void far initgraph(int far *,int far *,char far *);



int Vid;  //Global variable



int huge DetectSVGA256()

{

  printf("\n Which video mode would you like to use? \n\n");

  printf(" 0 - 320x200x256\n");

  printf(" 1 - 640x400x256\n");

  printf(" 2 - 640x480x256\n");

  printf(" 3 - 800x600x256\n");

  printf(" 4 - 1024x768x256\n\n");

  printf(" (Try mode 4, if possible) \n\n > ");

  scanf("%d",&Vid);

  return Vid;

}



void main(void)

{

      double xmin, xmax, ymin, ymax, x, y, x0, y0, R1, I1, Temp;

      double deltax, deltay, p, q, r, a, b;

      double c1[6] = {15.0,18.0,15.0,15.0,18.0,15.0};

      double c2[6] = {1.25e+7,13.0,1.5e+3,38.0,125.0,75.0};

      register int npix, npiy, k, np, nq;

      int Maxit, ipen, index;

      int graphdriver=DETECT, graphmode;



      printf("\n  Program DISKS.CPP \n");

      printf("\n\n  By Fausto A. A. Barbuto, May 14, 1994");

      printf("\n  Rio de Janeiro, Federal Republic of Brazil");

      printf("\n  E-mail: [e-mail]\n\n");

      printf("\n  Reference: Peitgen, H.-O., and Richter, P.H. :");

      printf("\n  'The Beauty of Fractals', Springer-Verlag, 1986\n\n");

      printf("\n                   Select a Julia set: \n\n");

      printf("   1: c = -0.123750 + 0.565080i  (Map 20, pg. 52) \n");

      printf("   2: c = -0.390540 - 0.586790i  (Map 22 & 25, pgs. 52, 77)\n");

      printf("   3: c =  0.310000 + 0.040000i  (Hmmm... Pretty good!)\n");

      printf("   4: c = -0.481762 - 0.531657i   \n");

      printf("   5: c =  0.273340 + 0.007420i  (Fausto's favourite)\n");

      printf("   6: c = -0.125000 + 0.649250i   \n");

      printf("\n> ");

      scanf("%d",&index);

      if ((index<1) || (index>6)) index = 1;



      if (index == 1) {xmin=-1.40;xmax=1.40;ymin=-1.4;ymax=1.4;Maxit=128;

               p=-0.123750;q= 0.565080;}

      if (index == 2) {xmin=-1.50;xmax=1.50;ymin=-1.5;ymax=1.5;Maxit=256;

               p=-0.390540;q=-0.586579;}

      if (index == 3) {xmin=-1.20;xmax=1.20;ymin=-1.2;ymax=1.2;Maxit=256;

               p= 0.310000;q= 0.040000;}

      if (index == 4) {xmin=-1.50;xmax=1.50;ymin=-1.5;ymax=1.5;Maxit=512;

               p=-0.481762;q=-0.531657;}

      if (index == 5) {xmin=-1.10;xmax=1.10;ymin=-1.1;ymax=1.1;Maxit=256;

               p= 0.273340;q= 0.007420;}

      if (index == 6) {xmin=-1.75;xmax=1.75;ymin=-1.5;ymax=1.5;Maxit=512;

               p=-0.125000;q= 0.649250;}

      clrscr();



      installuserdriver("Svga256",DetectSVGA256);

      initgraph(&graphdriver, &graphmode, "c:\\borlandc\\bgi");

      if (Vid == 0) {npix = 320; npiy = 200;}

      if (Vid == 1) {npix = 640; npiy = 400;}

      if (Vid == 2) {npix = 640; npiy = 480;}

      if (Vid == 3) {npix = 800; npiy = 600;}

      if (Vid == 4) {npix =1024; npiy = 768;}

      if((Vid<0) || (Vid)>4) Vid = 2;



      deltax = (xmax-xmin)/(npix-1);

      deltay = (ymax-ymin)/(npiy-1);



      cleardevice();

      for (np=0; np<=npix-1; np++) {

    x0 = xmin + (double)np*deltax;

    for (nq=0; nq<=npiy-1; nq++) {

    y0 = ymin + (double)nq*deltay;

    x = x0;

    y = y0;

    k  = 0;



     do {

       Temp = x*y;

       R1 = (x-y)*(x+y) + p;

       I1 = Temp + Temp + q;

       r = sqrt(R1*R1 + I1*I1);

       k++;



       if (r >= Maxit) {   //* Escaped points. *//

         ipen = 30 + k;

         putpixel(np,nq,ipen);

       }



       if (k == Maxit) {   //* Converged points. *//

//*

//*          The colour shades of the inner contours are defined here

//*          (as function of the distance between the current point [x,y]

//*          and an "invariant" point [x=R(z),y=I(z)]).

//*

         a = (x-R1)*(x-R1);

         b = (y-I1)*(y-I1);

         ipen = c1[index-1] + (int)(c2[index-1]*sqrt(a+b));

         putpixel(np,nq,ipen);

       }



       x = R1;

       y = I1;

     } while (r <= Maxit && k<=Maxit);

       }

       if(kbhit()) break;

     }



     getch();

     closegraph();

}