PK_SURF_degen_t

struct PK_SURF_degen_s
    {
    PK_SURF_degen_type_t type;
    PK_LOGICAL_t         have_position;
    PK_VECTOR_t          position;
    PK_LOGICAL_t         have_normal;
    PK_VECTOR1_t         normal;
    PK_UVBOX_t           uvbox;
    };

typedef struct PK_SURF_degen_s PK_SURF_degen_t;



A structure packaging information about a degeneracy on a surface.

Used in:

PK_SURF_degens_t

Each structure contains information on a single region where the surface is
degenerate.

The structure has the following fields :

'type'              Indicates the type of degeneracy.

'have_position'     Whether the degenerate region occupies a single position in
                    three-space. If set to PK_LOGICAL_true, then the position
                    is returned in 'position'.

'position'          Indicates the position of the degeneracy in three-space.

'have_normal'       Whether a normal can be calculated for the surface at the
                    degeneracy.

'normal'            The normal of the surface at the degeneracy, if available.

'uvbox'             The range of the degeneracy in parameter space. Note that
                    it is possible to have zero-width parameter ranges.