gluQuadricOrientation

gluQuadricOrientation: specify inside/outside orientation for quadrics.

C Specification

void gluQuadricOrientation(
    GLUquadric*	 quad,
    GLenum	 orientation)

quad: Specifies the quadrics object (created with gluNewQuadric).
orientation: Specifies the desired orientation. Valid values are GLU_OUTSIDE and GLU_INSIDE.

gluQuadricOrientation specifies what kind of orientation is desired for quadrics rendered with quad. The orientation values are as follows:

GLU_OUTSIDE: Quadrics are drawn with normals pointing outward (the initial value).
GLU_INSIDE: Quadrics are drawn with normals pointing inward.

Note that the interpretation of outward and inward depends on the quadric being drawn.