GPHIGS C FUNCTIONS - SET BACK REFLECTANCE PROPERTIES

SET BACK REFLECTANCE PROPERTIES

PSET_BACK_REFL_PROPS

CALL SEQUENCE

void pset_back_refl_props(

const Prefl_prop	*refl_prop	/* reflectance property data	*/

TYPES

typedef struct {
	Pint		type;		/* reflectance property type	*/
	union Prefl_prop_data {
		struct Prefl_prop_simple_refl {
			Pfloat	amb_coeff;	/* ambient reflection coefficient	*/
			Pfloat	diff_coeff;	/* diffuse reflection coefficient	*/
			Pfloat	spec_coeff;	/* specular reflection coefficient	*/
			Pgcolr	spec_colr;	/* specular colour	*/
			Pfloat	spec_exp;	/* specular exponent	*/
		} simple_refl;
	} data;
} Prefl_prop;


typedef struct {
	Pint	colr_type;	/* colour type	*/
	Pcolrv	colr_value;	/* colour value	*/
} Pgcolr;

typedef union {
	Pint	colr_ind;	/* colour index	*/
	Pcolr_rep	colr_rep;	/* colour representation	*/
} Pcolrv;

typedef union {
	Prgb	rgb;	/* red green blue colour specification	*/
	Pcieluv	cieluv;	/* CIE L*u*v* colour specification	*/
	Phls	hls;	/* hue lightness saturation colour specification	*/
	Phsv	hsv;	/* hue saturation value colour specification	*/
} Pcolr_rep;

PHIGS STATE

(PHOP,*,STOP,*)

EFFECT

A SET BACK REFLECTANCE PROPERTIES element is inserted in the open structure after element pointer or replaces the element indicated by element pointer, depending on edit mode. Element pointer then points to the SET BACK REFLECTANCE PROPERTIES element. The value specified by the parameter is associated with the element.

When an element of this type is interpreted, the current back reflectance properties entry in the traversal state list are set to the values associated with the element. These values are (possibly) used when displaying back-facing portions of subsequent area defining output primitives when the current back reflectance properties ASF in the traversal state list is INDIVIDUAL.

EXTENSION TO THE PHIGS STANDARD

If GPHIGS is in NRS mode, the effect of this function is different from the effect described in the standard.

In NRS mode, (see OPEN PIPE), the element is not stored in a structure. It is sent to the workstation on which the pipe is opened.

ERRORS

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