How would I go about determining whether a point P is enclosed by a tetrahedron A,B,C,D?
This is what I do not understand.
You are given a tetrahedron and asked to determine if a point is inside?
You cannot, because it can be inside or outside.
Or are you given a certain tetrahedron surface defined as,
And you are given P(x_0,y_0,z_0)
And asked to determine if P is inside f?
It looks very similar to that polygon test (whatever it is called) for 2-d.
if the point P is inside the tetrahedron.
one way of doing this is given at PNPOLY - Point Inclusion in Polygon Test - WR Franklin (WRF)
the faces at only one internal point (of a face) for positive a then P is an
internal point of the tetrahedron, if it meets an edge or a vertex, then
perturb the unit vector to avoid this.
(Such a ray from an external point will meet the faces either twice or zero