PSBRFP(3g) — Subroutines

Name

PSBRFP − Specifies the surface properties of the back-facing portions of area primitives.

Operating States: PHOP, ∗, STOP, ∗
PHIGS PLUS function
Creates a structure element

Old Syntax

DSBAP (AMB, DIFF, SPEC, BSPCCT, ICOLR, COLR, SPECXP, TRANS)

Argument       Data Type      Access    Description
---------------------------------------------------------------------------
AMB            Real           Read      Ambient reflection coefficient
DIFF           Real           Read      Diffuse reflection coefficient
SPEC           Real           Read      Specular reflection coefficient
BSPCCT         Integer        Read      Specular color type
ICOLR          Integer        Read      Specular indexed color
COLR(3)        Array of       Read      Specular direct color
               reals
SPECXP         Real           Read      Specular exponent
TRANS          Real           Read      Transparency coefficient
---------------------------------------------------------------------------

New Syntax

PSBRFP (RPTYPE, LDR, DATREC)

Argument       Data Type      Access   Description
---------------------------------------------------------------------------
RPTYPE         Integer        Read     Reflectance properties type
LDR            Integer        Read     Length of the data record array
DATREC(LDR)    Character ∗80 Read     Data record
---------------------------------------------------------------------------

Constants

Defined Argument     Constant    Description
---------------------------------------------------------------------------
RPTYPE               PSRPT       Simple reflectance
Color types          PINDIR      Indirect (indexed) color
                     PRGB        Direct specification of red, green, and
                                 blue
                     PCIE        Direct specification in the format of the
                                 Commission Internationale de l’Eclairage
                     PHSV        Direct specification of hue, saturation,
                                 and value
                     PHLS        Direct specification of hue, lightness,
                                 and saturation
---------------------------------------------------------------------------

Description

PSBRFP specifies the surface properties of the back-facing portions of area primitives. The argument values of this function help to define the lighting calculation conceptually applied at one or more points on the back-facing areas of the primitive Digital PHIGS illuminates and shades. The aspects defined by the PSBIC function also affect the back-facing areas. These aspects, in conjunction with the face processing mode, determine the appearance of the back-facing area.

Depending on the current edit mode, the function either inserts the new structure element directly after the element indicated by the pointer or replaces the element indicated by the pointer. The pointer then points to the new set back reflectance properties element.

If Digital PHIGS is in immediate mode, it performs this function immediately, but the function does not create a structure element.

The new function syntax conforms to the ISO Fortran standard. Digital recommends that you code using the new function syntax.

Data Record Information

If RPTYPE is PSRPT, the data record is as follows:

INTEGER IL    = 2+∗   Number of integer elements
INTEGER IA(1) =       Color type
INTEGER IA(2) =       Number of color value components (NCC)
INTEGER RL    = 4+∗   Number of real elements
REAL RA(1)    =       Ambient reflection coefficient
REAL RA(2)    =       Diffuse reflection coefficient
REAL RA(3)    =       Specular reflection coefficient
REAL RA(4)    =       Specular exponent
REAL RA(5)    =       Transparency coefficient (optional)
     SL       = 0
     LSTR     = ()
     STR      = ()
     If the color type is PINDIR:

         IA(3) =   Specular color index
     If the color type is PRGB, PCIE, PHSV, or PHLS:
         RA     =   Elements 5 through 4+NCC contain the color values

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