Triangulo de sierpinski

/* gasket.c */
/* E. Angel, Interactive Computer Graphics */
/* A Top-Down Approach with OpenGL, Third Edition */
/* Addison-Wesley Longman, 2003 */
/* Two-Dimensional Sierpinski Gasket */
/* Generated Using Randomly Selected Vertices */
/* And Bisection */
#include <GL/glut.h>
#include <stdlib.h>
void myinit(void)
{
/* attributes */
glClearColor(1.0, 1.0, 1.0, 1.0); /* white background */
glColor3f(1.0, 0.0, 0.0); /* draw in red */
/* set up viewing */
/* 500 x 500 window with origin lower left */
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0.0, 500.0, 0.0, 500.0);
glMatrixMode(GL_MODELVIEW);
}
void display( void )
{
/* define a point data type */
typedef GLfloat point2[2];
point2 vertices[3]={{0.0,0.0},{250.0,500.0},{500.0,0.0}}; /* A triangle */
int i, j, k;
int rand(); /* standard random number generator */
point2 p ={75.0,50.0}; /* An arbitrary initial point inside traingle */
glClear(GL_COLOR_BUFFER_BIT); /*clear the window */

/* compute and plots 5000 new points */
for( k=0; k<5000; k++)
{
j=rand()%3; /* pick a vertex at random */

/* Compute point halfway between selected vertex and old point */
p[0] = (p[0]+vertices[j][0])/2.0;
p[1] = (p[1]+vertices[j][1])/2.0;
/* plot new point */
glBegin(GL_POINTS);
glVertex2fv(p);
glEnd();
}
glFlush(); /* clear buffers */
}
void main(int argc, char** argv)
{
/* Standard GLUT initialization */
glutInit(&argc,argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); /* default, not needed */
glutInitWindowSize(500,500); /* 500 x 500 pixel window */
glutInitWindowPosition(0,0); /* place window top left on display */
glutCreateWindow("Sierpinski Gasket"); /* window title */
glutDisplayFunc(display); /* display callback invoked when window opened */
myinit(); /* set attributes */
glutMainLoop(); /* enter event loop */
}