Julia sets :: OPENGL Program and C program

OPENGl Program and C program for Julia sets 

//JULIA sets    Ex. No 12 (b)              

#include <GL/glut.h>

int dwell(double sx,double sy)

{

      int iteration,itermax=100;

      double dx,dy,tmp,fsq,cx=-0.5,cy=0.5;

      dx = sx; dy = sy;

      fsq=sx*sx+sy*sy;

      for (iteration=1;iteration<=itermax && fsq<=4;iteration++)

      {

            tmp=dx;

            dx = dx*dx-dy*dy+cx;

            dy = 2.0*tmp*dy+cy;

            fsq=dx*dx+dy*dy;

      }

      return iteration;

}

void color(int x,int y,int f)

void color(int x,int y,int f)            // inside one color and outside one color

{

      if(f==1)

      {

            glColor3f(1.0,0.0,0.0);

            glBegin(GL_POINTS);

            glVertex2i(x,y);

            glEnd();

      }

      else if(f==2)

      {

        glColor3f(0.0,1.0,0.0);

            glBegin(GL_POINTS);

            glVertex2i(x,y);

            glEnd();

      }

      glFlush();

}

void init()

{

      //select clearing (background) color

    glClearColor(0.0, 0.0, 0.0, 0.0);

    //initialize viewing values

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    gluOrtho2D(0.0, 640.0, 0.0, 440.0);

}

void display()

{

      double sx,sy,tmp,zoom=1.5;

      int iteration,hx,hy;

      int itermax = 100;            /* how many iterations to do  */

      int hxres = 200;        /* horizonal resolution       */

      int hyres = 200;        /* vertical resolution        */

      for (hy=1;hy<=hyres;hy++)

      {

            sy=(hy-hyres/2)/(0.5*zoom*hyres);

            for (hx=1;hx<=hxres;hx++)

            {

                  sx=1.5*(hx-hxres/2)/(0.5*zoom*hxres);

                  iteration=dwell(sx,sy);

                  if (iteration<=itermax)

                        color(hx,hy,1);

                  else

                        color(hx,hy,2);

            }

      }

}

int main(int argc, char** argv)

{

    //Initialise GLUT with command-line parameters.

    glutInit(&argc, argv);

   

    //Set Display Mode

    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);

   

    //Set the window size

    glutInitWindowSize(640,440);

   

    //Set the window position

    glutInitWindowPosition(100,100);

   

    //Create the window

    glutCreateWindow("A Simple OpenGL Windows Application with GLUT");

   

    //Call init (initialise GLUT

    init();

   

    //Call "display" function

    glutDisplayFunc(display);

   

    //Enter the GLUT event loop

    glutMainLoop();

      //exit(0);

    return 0;

}

output:

C program code :

#include <stdio.h>

#include <math.h>

#include <stdlib.h>

#include<graphics.h>

int dwell(double sx,double sy)

{

int iteration,itermax=100;

double dx,dy,tmp,fsq,cx=-0.5,cy=0.5;

dx = sx; dy = sy;

fsq=sx*sx+sy*sy;

for (iteration=1;iteration<=itermax && fsq<=4;iteration++)

{

tmp=dx;

dx = dx*dx-dy*dy+cx;

dy = 2.0*tmp*dy+cy;

fsq=dx*dx+dy*dy;

}

return iteration;

}

void color(int x,int y,int f)

{

putpixel(x,y,f);

}

void main()

{

double sx,sy,tmp,zoom=1.5;

int iteration,hx,hy;

int itermax = 100; /* how many iterations to do */

int hxres = 200; /* horizonal resolution */

int hyres = 200; /* vertical resolution */

int gd,gm;

detectgraph(&gd,&gm);

initgraph(&gd,&gm,"z:\\tc\\bgi");

for (hy=1;hy<=hyres;hy++)

{

sy=(hy-hyres/2)/(0.5*zoom*hyres);

for (hx=1;hx<=hxres;hx++)

{

sx=1.5*(hx-hxres/2)/(0.5*zoom*hxres);

iteration=dwell(sx,sy);

if (iteration<=itermax)

color(hx,hy,1);

else

color(hx,hy,2);

}

}

getch();

closegraph();

}