CG 7 - 3D SIERPINSKI GASKET

7. Design, develop and implement recursively subdivide a tetrahedron to form 3D Sierpinski gasket. The number of recursive steps is to be specified by the user. Sierpinski gasket

#include<stdio.h>
#include<math.h>
#include<iostream>
#include<GL/glut.h>
using namespace std;
float v[4][3] = { { 0.0,0.0,1.0 },{ 0,1,-1 },{ -0.8,-0.4,-1 },{ 0.8,-0.4,-1 } };
int n;

void triangle(float a[], float b[], float c[])
{
glBegin(GL_POLYGON);
glVertex3fv(a);
glVertex3fv(b);
glVertex3fv(c);
glEnd();
}

void divide_triangle(float a[], float b[], float c[], int m)
{
float v1[3], v2[3], v3[3];
int i;
if (m>0)
{
for (i = 0; i<3; i++) v1[i] = (a[i] + b[i]) / 2;
for (i = 0; i<3; i++) v2[i] = (a[i] + c[i]) / 2;
for (i = 0; i<3; i++) v3[i] = (b[i] + c[i]) / 2;
divide_triangle(a, v1, v2, m - 1);
divide_triangle(c, v2, v3, m - 1);
divide_triangle(b, v3, v1, m - 1);
}
else (triangle(a, b, c));
}

void tetrahedron(int m)
{
glColor3f(1.0, 0.0, 0.0);
divide_triangle(v[0], v[1], v[2], m);
glColor3f(0.0, 1.0, 0.0);
divide_triangle(v[3], v[2], v[1], m);
glColor3f(0.0, 0.0, 1.0);
divide_triangle(v[0], v[3], v[1], m);
glColor3f(1.0, 1.0, 0.0);
divide_triangle(v[0], v[2], v[3], m);
}

void display()
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-2.0, 2.0, -2.0, 2.0, -10.0, 10.0);
glMatrixMode(GL_MODELVIEW);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
tetrahedron(n);
glFlush();
glutPostRedisplay();
}

int main(int argc, char* argv[])
{
cout << "Enter the number of divisions: ";
cin >> n;
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(500, 500);
glutInitWindowPosition(0, 0);
glutCreateWindow("3D Gasket");
glutDisplayFunc(display);
glEnable(GL_DEPTH_TEST);
glClearColor(1.0, 1.0, 1.0, 1.0);
glutMainLoop();
return 0;
}

OUTPUT :

( click on image to zoom )