NAME

SET BACK INTERIOR REFLECTANCE EQUATION - create structure element to set current back interior reflectance equation

SYNOPSIS

C Syntax

void

pset_back_refl_eqn ( equation )

Pint

equation;

back reflectance equation

FORTRAN Syntax

SUBROUTINE psbire ( REFLEQ )

INTEGER

REFLEQ

back reflectance equation

Required PHIGS Operating States

(PHOP, * ,STOP, * )

DESCRIPTION

Purpose

SET BACK INTERIOR REFLECTANCE EQUATION creates a structure element to set the current back interior reflectance equation.

When the current back interior reflectance equation ASF is set to INDIVIDUAL, the current value of this attribute applies to the following output primitives:

FILL AREA

FILL AREA 3

FILL AREA SET

FILL AREA SET 3

FILL AREA SET 3 WITH DATA

NON-UNIFORM B-SPLINE SURFACE

SET OF FILL AREA SET 3 WITH DATA

QUADRILATERAL MESH 3 WITH DATA

TRIANGLE STRIP 3 WITH DATA

This is a SunPHIGS Extension function based on PHIGS PLUS and is not part of the PHIGS standard.

C Input Parameter

equation

The reflectance equation. The values defined in phigs.h are:

1   PREFL_NONE              No Reflectance Calculation Performed
2   PREFL_AMBIENT           Use Ambient Term
3   PREFL_AMB_DIFF          Use Ambient and Diffuse Terms
4   PREFL_AMB_DIFF_SPEC     Use Ambient, Diffuse, and Specular Terms

FORTRAN Input Parameter

The following data types are predefined in phigs77.h.

REFLEQ

The reflectance equation. The values are:

1   PRNONE     No Reflectance Calculation Performed
2   PRAMB      Use Ambient Term

3   PRAMBD     Use Ambient and Diffuse Terms
4   PRAMDS     Use Ambient, Diffuse, and Specular Terms

Execution

Depending on the edit mode, a SET BACK INTERIOR REFLECTANCE EQUATION element with the value reflectance equation is inserted into the open structure after the element pointer or replaces the element pointed at by the element pointer. The element pointer is then updated to point to this SET BACK INTERIOR REFLECTANCE EQUATION element.

At traversal time, if the specified reflectance equation is not defined, then equation one is substituted.

Back face attributes (such as back area properties, back interior colour, back interior reflectance equation, back interior shading method, back interior style, and back interior style index) are used only when the face distinguishing mode has the value Yes and are applied to only the back facing portion of area defining primitives. See SET FACE DISTINGUISHING MODE (3PP) for details on front and back face determination.

When the current back interior reflectance equation ASF is set to INDIVIDUAL, area-defining output primitives which follow in the structure network are filled using the current back interior reflectance equation.

When the current back interior reflectance equation ASF is set to BUNDLED, the back interior reflectance equation is taken from the workstation extended representation indicated by the current interior index. In this case, the back interior reflectance equation set with SET BACK INTERIOR REFLECTANCE EQUATION has no effect.

ERRORS

005

Ignoring function, function requires state (PHOP, * ,STOP, * )

SEE ALSO

SET FACE DISTINGUISHING MODE (3PP)

SET INDIVIDUAL ASF (3P)

SET INTERIOR REPRESENTATION PLUS (3PP)

SET REFLECTANCE EQUATION (3PP)