GPBSCI - Set Back Specular Color Index

Purpose

Use GPBSCI to insert a Set Back Specular Color Index structure element into the open structure following the element pointer or to replace the element pointed at by the element pointer with a Set Back Specular Color Index structure element depending on the current edit mode.

This structure element specifies an entry in the workstation's rendering color table that defines the color values. At structure traversal time, the graPHIGS API uses these values for the specular highlights. The specular highlights are produced by lighting calculations in area geometries.

Face distinguish mode must be set to 2=COLOR_SURFACE_PROPERTIES If face distinguish mode is 1=NONE , then the graPHIGS API uses the current specular color in lighting calculations for the back facing portions of the surfaces.

This attribute sets the same traversal state as the Set Back Specular Color Direct (GPBSCD) subroutine. The traversal default for back specular color is a color index of 1.

If the workstation does not support the specified color index value or the specified index is outside the color table limit, then the color index defaults to a value of 1.

Parameters