EVALUATE VIEW MAPPING MATRIX 3

PEVAL_VIEW_MAP_MATRIX3

CALL SEQUENCE

void peval_view_map_matrix3(

const Pview_map3	*mapping	/* view mapping	*/
Pint	*error_ind	/* (out) error indicator	*/
Pmatrix3	result	/* (out) view mapping matrix	*/

)

TYPES

typedef struct {
	Plimit 	win;	/* window limits in VRC	*/
	Plimit3	proj_vp;	/* viewport limits in NPC space	*/
	Pproj_type 	proj_type;	/* projection type 	*/
	Ppoint3	proj_ref_point;	/* projection reference point in VRC	*/
	Pfloat 	view_plane;	/* view plane distance in VRC	*/
	Pfloat 	back_plane;	/* back plane distance in VRC	*/
	Pfloat 	front_plane;	/* front plane distance in VRC	*/
} Pview_map3;

typedef Pfloat Pmatrix3[4][4];

typedef struct {
	Pfloat	x_min;	/* minimum x 	*/
	Pfloat	x_max;	/* maximum x 	*/
	Pfloat	y_min;	/* minimum y 	*/
	Pfloat	y_max;	/* maximum y 	*/
} Plimit;

typedef struct {
	Pfloat	x_min;	/* minimum x 	*/
	Pfloat	x_max;	/* maximum x 	*/
	Pfloat	y_min;	/* minimum y 	*/
	Pfloat	y_max;	/* maximum y 	*/
	Pfloat	z_min;	/* minimum z 	*/
	Pfloat	z_max;	/* maximum z 	*/
} Plimit3;

typedef enum {
	PTYPE_PARAL,
	PTYPE_PERSPECT
} Pproj_type;

typedef struct {
	Pfloat 	x;	/* x coordinate	*/
	Pfloat 	y;	/* y coordinate	*/
	Pfloat 	z;	/* z coordinate	*/
} Ppoint3;

PHIGS STATE

EFFECT

Returns a homogeneous 4 x 4 matrix allowing a 3D view reference coordinate (VRC) space window to be projected into a 3D viewport in normalized projection coordinate (NPC) space. This projection, which can be in parallel or in perspective, is defined according to the projection reference point (PRP) proj_ref_point, defined in VRC.

- Parallel projection: the view volume sides are parallel to the vector passing through the PRP and the centre of the view plane.

- Perspective projection: the view volume sides converge towards the PRP.

ERRORS

2

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

151

Ignoring function, invalid window: XMIN>>=XMAX, YMIN>>=YMAX, ZMIN>>ZMAX, UMIN>>=UMAX or VMIN>>=VMAX

152

Ignoring function, invalid viewport: XMIN>>=XMAX, YMIN>>=YMAX or ZMIN>>ZMAX

158

Ignoring function, front plane and back plane distances are equal when: extent of the projection viewport is non zero

162

Ignoring function, the projection reference point is between the front and back planes

163

Ignoring function, the projection reference point cannot be positioned on the view plane

164

Ignoring function, the back plane is in front of the front plane

155

Ignoring function, the projection viewport limits are not within NPC range

SEE ALSO

set view representation, evaluate view orientation matrix