/* Recursive subdivision of tetrahedron to form
3D Sierpinski gasket */
#include
#include
typedef float point[3];
void menu(int);
/* initial tetrahedron */
point v[]={{0.0, 0.0, 1.0}, {0.0, 0.942809, -0.33333},
{-0.816497, -0.471405, -0.333333}, {0.816497, -0.471405, -0.333333}};
static GLfloat theta[] = {0.0,0.0,0.0};
int n;
void triangle( point a, point b, point c)
/* display one triangle using a line loop for wire frame, a single
normal for constant shading, or three normals for interpolative shading */
{
glBegin(GL_POLYGON);
glNormal3fv(a);
glVertex3fv(a);
glVertex3fv(b);
glVertex3fv(c);
glEnd();
}
void divide_triangle(point a, point b, point c, int m)
{
/* triangle subdivision using vertex numbers
righthand rule applied to create outward pointing faces */
point v1, v2, v3;
int j;
if(m>0)
{
for(j=0; j<3; j++) v1[j]=(a[j]+b[j])/2;
for(j=0; j<3; j++) v2[j]=(a[j]+c[j])/2;
for(j=0; j<3; j++) v3[j]=(b[j]+c[j])/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)); /* draw triangle at end of recursion */
}
void tetrahedron( int m)
{
/* Apply triangle subdivision to faces of tetrahedron */
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(0.0,0.0,0.0);
divide_triangle(v[0], v[2], v[3], m);
}
void menu(int id)
{
if (id != 20) {
n= id; }
else { exit(0); }
}
void display(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
tetrahedron(n);
glFlush();
}
void myReshape(int w, int h)
{
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if (w <= h)
glOrtho(-2.0, 2.0, -2.0 * (GLfloat) h / (GLfloat) w,
2.0 * (GLfloat) h / (GLfloat) w, -10.0, 10.0);
else
glOrtho(-2.0 * (GLfloat) w / (GLfloat) h,
2.0 * (GLfloat) w / (GLfloat) h, -2.0, 2.0, -10.0, 10.0);
glMatrixMode(GL_MODELVIEW);
glutPostRedisplay();
}
void
main(int argc, char **argv)
{
int m_menu;
if(argc>1) n=atoi(argv[1]);
else n=4;
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(500, 500);
glutCreateWindow("3D Gasket");
m_menu= glutCreateMenu(menu);
glutAddMenuEntry("1",1);
glutAddMenuEntry("2",2);
glutAddMenuEntry("3",3);
glutAddMenuEntry("4",4);
glutAddMenuEntry("5",5);
glutAddMenuEntry("6",6);
glutAddMenuEntry("7",7);
glutAddMenuEntry("8",8);
glutAddMenuEntry("9",9);
glutAddMenuEntry("10",10);
glutAddMenuEntry("11",11);
// glutAddMenuEntry("12",12);
// glutAddMenuEntry("13",13);
glutAddMenuEntry("Exit",20);
glutAttachMenu(GLUT_LEFT_BUTTON);
glutReshapeFunc(myReshape);
glutDisplayFunc(display);
glEnable(GL_DEPTH_TEST);
glClearColor (1.0, 1.0, 1.0, 1.0);
glutMainLoop();
}
Recursive subdivision of tetrahedron to form 3D Sierpinski gasket using OpenGL
byPro Softify
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