SET BACK AREA PROPERTIES(3P+) — MISC. REFERENCE MANUAL PAGES

NAME

SET BACK AREA PROPERTIES − create a structure element to set the back area properties

SYNOPSIS

C Syntax

void
psetbackareaprop ( properties )
Pareaprops∗properties;back area properties

FORTRAN Syntax

SUBROUTINE psbap ( AMB, DIF, SPEC, COLMOD, ICOLR, COLR, EXP, TRANS )
REALAMBambient reflectance coefficient
REALDIFdiffuse reflectance coefficient
REALSPECspecular reflectance coefficient
INTEGERCOLMODcolour model
INTEGERICOLRindirect colour
REALCOLR(3)specular colour
REALEXPspecular exponent
REALTRANStransparency coefficient

Required PHIGS Operating States

(PHOP, ∗, STOP, ∗)

DESCRIPTION

Purpose

SET BACK AREA 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 3 WITH DATA

• FILL AREA SET 3 WITH DATA

• NON-UNIFORM B-SPLINE SURFACE

• POLYHEDRON 3 WITH DATA

• QUADRILATERAL MESH 3 WITH DATA

• TRIANGLE STRIP 3 WITH DATA

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

C Input Parameters

All of the following data types are predefined in phigs.h.

properties
A pointer to a Pareaprops structure that specifies the back area properties. Pareaprops is defined as follows:

typedef struct {
Pfloatambient_coef;/∗ ambient reflectance coefficient ∗/
Pfloatdiffuse_coef;/∗ diffuse reflectance coefficient ∗/
Pfloatspecular_coef;/∗ specular reflectance coefficient ∗/
Pgcolrspecular_colour;/∗ specular colour ∗/
Pfloatspecular_exp;/∗ specular exponent ∗/
Pfloattranspar_coef;/∗ transparency coefficient ∗/
} Pareaprops;

Pgcolr is defined as:

typedef struct {
Pint type;/∗ indirect, RGB, CIE, HSV, HLS ∗/
union {
   Pintindex;/∗ colour table index ∗/
   struct {
Pfloatx;/∗ red, hue, etc. ∗/
Pfloaty;/∗ green, saturation, lightness, etc. ∗/
Pfloatz;/∗ blue, value, saturation, etc. ∗/
   } general;
} val;
} Pgcolr;

FORTRAN Input Parameters

All of the following data types are predefined in phigs77.h.

AMBThe ambient reflectance coefficient.

DIFThe diffuse reflectance coefficient.

SPECThe specular reflectance coefficient.

COLMOD
The colour model. The predefined values are:

0PINDIRColour Index Specified
1PRGBRed, Green, and Blue
2PCIECIE Colour Model
3PHSVHue, Saturation, and Value
4PHLSHue, Lightness, and Saturation

ICOLR
An integer value which is an index into the workstation colour table for determining the specular colour. ICOLR is used if COLMOD is set to PINDIR.

COLR(3)
The specular colour. An array of reals containing the specular colour. COLR(3) is used if COLMOD is set to other than PINDIR.

COLR(1) = Red, Hue, etc.
COLR(2) = Green, Saturation, Lightness, etc.
COLR(3) = Blue, Value, Saturation, etc.

EXPThe specular exponent.

TRANS
The transparency coefficient.

Execution

Depending on the edit mode, a SET BACK AREA 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 AREA 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 distiguishing mode has the value Yes and are applied to only the back facing portion of area defining primitives. See SET FACE DISTIGUISHING MODE (3P+) 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 AREA PROPERTIES has no effect.

ERRORS

005Ignoring function, function requires state (PHOP,∗,STOP,∗)

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