NAME

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

SYNOPSIS

C Syntax

void

pset_refl_eqn ( equation )

Pint

equation;

reflectance equation

FORTRAN Syntax

SUBROUTINE psireq ( REFLEQ )

INTEGER

REFLEQ

reflectance equation

Required PHIGS Operating States

(PHOP, * ,STOP, * )

DESCRIPTION

Purpose

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

When the current interior reflectance equation Aspect Source Flag (ASF) is set to INDIVIDUAL, the current value of this attribute defines the interior reflectance equation to be applied 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 possible 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 type is predefined in phigs77.h.

REFLEQ

The reflectance equation. The possible 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 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 REFLECTANCE EQUATION element.

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

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

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

ERRORS

002

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

SEE ALSO

SET INDIVIDUAL ASF (3P)

SET INTERIOR REPRESENTATION PLUS (3PP)