my purpose is to create a big semi-transparent cube box, and inside of it contains a non-transparent sphere.

here is my simplified code:

GLUquadricObj* object;
object = gluNewQuadric();
gluQuadricNormals(object, 0);

glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);

while(true)
{
glPushMatrix();
drawCube(); //this function contains glVertex3fs to draw a cube.

glPushMatrix();
glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
gluSphere(object, 0.25, 25, 25);
glPopMatrix();

glPopMatrix();
}

the problem i encounter is, the sphere seems appear infront of the box (instead of inside of the box).