NAME

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

SYNOPSIS

C Syntax

void
pset_back_refl_props ( properties )
Prefl_props∗properties;back surface area properties

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

• GENERALIZED DRAWING PRIMITIVE (Fill Area Primitives)

• GENERALIZED DRAWING PRIMITIVE 3 (Fill Area Primitives)

• SET OF FILL AREA SET 3 WITH DATA

• NON-UNIFORM B-SPLINE SURFACE

• QUADRILATERAL MESH 3 WITH DATA

• TRIANGLE STRIP 3 WITH DATA

C Input Parameters

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 {
Pfloatambient_coef;/∗ ambient reflectance coefficient ∗/
Pfloatdiffuse_coef;/∗ diffuse reflectance coefficient ∗/
Pfloatspecular_coef; /∗ specular reflectance coefficient ∗/
Pgcolrspecular_colr; /∗ specular colour ∗/
Pfloatspecular_exp;/∗ specular exponent ∗/
Pfloattranspar_coef; /∗ transparency coefficient ∗/
} Prefl_props;

Pgcolr is defined as:

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

The color type is one of the following:

0PINDIRECT
1PMODEL_RGB
2PMODEL_CIELUV
3PMODEL_HSV
4PMODEL_HLS

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 reflectance characteristics, 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 (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 REFLECTANCE PROPERTIES has no effect. 

ERRORS

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

SEE ALSO

SET REFLECTANCE PROPERTIES (3P+)
SET FACE DISTINGUISHING MODE (3P+)
SET INDIVIDUAL ASF (3P)
SET INTERIOR REPRESENTATION PLUS (3P+)
SET FACE CULLING MODE (3P+)
FILL AREA (3P)
FILL AREA 3 (3P)
FILL AREA SET (3P)
FILL AREA SET 3 (3P)
FILL AREA SET 3 WITH DATA (3P+)
SET OF FILL AREA SET 3 WITH DATA (3P+)
QUADRILATERAL MESH 3 WITH DATA (3P+)
TRIANGLE STRIP 3 WITH DATA (3P+)

September 02, 1992