The Tutorial and OpenGL

The shaded triangle drawn in the tutorial is accomplished with the default shading method GL_SMOOTH and without lighting. Defining the triangle along with its vertices and vertex colors is accomplished with the following OpenGL function calls.

glBegin(GL_TRIANGLES);
   glColor3fv(color1);
   glVertex3dv(vertex1);

   glColor3fv(color2);
   glVertex3dv(vertex2);

   glColor3fv(color3);
   glVertex3dv(vertex3);
glEnd();