Generate fractal patterns by using Koch curves.

#include <GL/glut.h>

#include <math.h>

GLfloat oldx=-0.7,oldy=0.5;

void drawkoch(GLfloat dir,GLfloat len,GLint iter)
{

GLdouble dirRad = 0.0174533 * dir ; 

GLfloat newX = oldx + len * cos(dirRad);

GLfloat newY = oldy + len * sin(dirRad);

if (iter==0)
         {

glVertex2f(oldx, oldy);

glVertex2f(newX, newY);

oldx = newX;

oldy = newY;

      }

else
    {

iter--;
//draw the four parts of the side _/\_

              drawkoch(dir, len, iter);

             dir += 60.0;

            drawkoch(dir, len, iter);

           dir -= 120.0;

          drawkoch(dir, len, iter);

         dir += 60.0;

 drawkoch(dir, len, iter);

}

}

void display()

{

 glClearColor(1.0,1.0,1.0,0); 

         glColor3f(0.0, 0.0, 0.0);     
       
 glClear( GL_COLOR_BUFFER_BIT );

 glBegin(GL_LINES);


 /*
drawkoch(0.0,0.5,1);

      drawkoch(-120.0, 0.5, 1);

  drawkoch(120.0,0.5,1);

 *//*

 drawkoch(0.0,0.15,2);

 drawkoch(-120.0, 0.15, 2);

drawkoch(120.0,0.15,2);
*/


 drawkoch(0.0,0.05,3);

 drawkoch(-120.0, 0.05, 3);

 drawkoch(120.0,0.05,3);
 

 glEnd();

 glFlush();

}


int main(int argc, char** argv)

{

glutInit(&argc,argv);

glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);     

glutInitWindowSize(500,500);   

glutInitWindowPosition(0,0);

glutCreateWindow("Koch Curves");   

glutDisplayFunc(display); 

glutMainLoop();


}