#define VIEW_ORTHO   0
#define VIEW_FRUSTUM 1
 
void switchView() {
    ...
    view = !view;
    (view ? glFrustum : glOrtho)(5 * -((float)w / min), 5 * ((float)w / min), 5 * -((float)h / min), 5 * ((float)h / min), 5.0, 100.0);
}