NAME

SET BACK REFLECTANCE PROPERTIES - create structure element to set back area properties

SYNOPSIS

C Syntax

void

pset_back_refl_props ( properties )

Prefl_props

* properties;

back surface area properties

FORTRAN Syntax

SUBROUTINE psbap ( AMB, DIF, SPEC, COLTYPE, ICOLR, COLR, EXP, TRANS )

REAL         AMB          ambient reflectance coefficient
REAL         DIF          diffuse reflectance coefficient
REAL         SPEC         specular reflectance coefficient
INTEGER      COLTYPE      colour type
INTEGER      ICOLR        indirect colour
REAL         COLR(3)      specular colour
REAL         EXP          specular exponent
REAL         TRANS        transparency coefficient

Required PHIGS Operating States

(PHOP, * ,STOP, * )

DESCRIPTION

Purpose

SET BACK REFLECTANCE PROPERTIES creates a structure element to set the back area properties.

When the current back area properties 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

properties

A pointer to a Prefl_props structure that specifies the back area properties. Prefl_props is defined in phigs.h as follows:

typedef struct {

Pfloat

ambient_coef;

/* ambient reflectance coefficient * /

Pfloat   diffuse_coef;    /* diffuse reflectance coefficient * /
Pfloat   specular_coef;   /* specular reflectance coefficient * /
Pgcolr  specular_colr;   /* specular colour * /
Pfloat   specular_exp;    /* specular exponent * /
Pfloat   transpar_coef;   /* transparency coefficient * /

} Prefl_props;

Pgcolr is defined as:

typedef struct {

Pint

type;

/* indirect, RGB, CIE, HSV, HLS * /

union {

Pint

ind;

/* colour table index * /

struct {

         Pfloat          x;     /* red, hue, and so on * /
         Pfloat          y;     /* green, saturation, lightness, and so on * /
         Pfloat          z;     /* blue, value, saturation, and so on * /
    } general;
  } val;
} Pgcolr;

The color type is one of the following:

0   PINDIRECT         Indirect
1   PMODEL_RGB        Red, Green, and Blue
2   PMODEL_CIELUV     CIE Colour Model
3   PMODEL_HSV        Hue, Saturation, and Value
4   PMODEL_HLS        Hue, Lightness, and Saturation

FORTRAN Input Parameters

The following data types are predefined in phigs77.h.

AMB

The ambient reflectance coefficient.

DIF

The diffuse reflectance coefficient.

SPEC

The specular reflectance coefficient.

COLTYPE

The colour type. The predefined values are:

0   PINDIR   Indirect
1   PRGB     Red, Green, and Blue
2   PCIE     CIE Colour Model
3   PHSV     Hue, Saturation, and Value
4   PHLS     Hue, Lightness, and Saturation

ICOLR An integer value that is an index into the workstation colour table for

determining the specular colour. ICOLR is used if COLTYPE is set to PINDIR.

COLR(3)

The specular colour. An array of reals containing the specular colour. COLR(3) is

used if COLTYPE is set to other than PINDIR.

COLR(1) = Red, Hue, and so on

COLR(2) = Green, Saturation, Lightness, and so on

COLR(3) = Blue, Value, Saturation, and so on

EXP

The specular exponent.

TRANS The transparency coefficient.

Execution

Depending on the edit mode, a SET BACK REFLECTANCE PROPERTIES element 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 REFLECTANCE PROPERTIES element.

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 only to 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 area properties ASF is set to INDIVIDUAL, area-defining output primitives, which follow in the structure network and are subject to back face attributes, are filled using the current back area properties.

When the current back area properties ASF is set to BUNDLED, the back area properties are taken from the workstation extended representation indicated by the current interior index. In this case, the back area properties set with SET BACK REFLECTANCE PROPERTIES has no effect.

ERRORS

005

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

SEE ALSO

SET REFLECTANCE PROPERTIES (3PP)

SET FACE DISTINGUISHING MODE (3PP)

SET INDIVIDUAL ASF (3P)

SET INTERIOR REPRESENTATION PLUS (3PP)

SET FACE CULLING MODE (3PP)