true if the barycentric coordinates are validTriangle.getBarycoords
bool getBarycoords(graphene.point3_d.Point3D p, out graphene.vec2.Vec2 res)Computes the barycentric coordinates of the given point p.
The point p must lie on the same plane as the triangle t; if the point is not coplanar, the result of this function is undefined.
If we place the origin in the coordinates of the triangle's A point, the barycentric coordinates are u, which is on the AC vector; and v which is on the AB vector:

The returned #graphene_vec2_t contains the following values, in order:
res.x = ures.y = v
Parameters
p | a #graphene_point3d_t |
res | return location for the vector with the barycentric coordinates |