void PEXOCCSetParaSurfCharacteristics(
PEXOCC context,
int psc_type,
PEXPSCData *characteristics
)
void PEXSetParaSurfCharacteristics(
Display *display,
XID resource_id,
PEXOCRequestType req_type,
int psc_type,
PEXPSCData *characteristics
)
- context
- An OC context returned by a successful
PEXCreateOCC call.
- display (OCC)
- A pointer to a display structure returned by
a successful XOpenDisplay call.
- resource_id (OCC)
- The resource identifier of the renderer or structure.
- req_type (OCC)
- The request type for the output command (PEXOCRender,
PEXOCStore, PEXOCRenderSingle or
PEXOCStoreSingle).
- psc_type
- The parametric surface characteristic type
(PEXPSCNone, PEXPSCImpDep, PEXPSCIsoCurves,
PEXPSCMCLevelCurves or PEXPSCWCLevelCurves).
- characteristics
- A pointer to data defining the parametric surface characteristics.
None.
Invoke PEXOCCSetParaSurfCharacteristics to create an
attribute output command which sets the parametric surface
characteristics in the renderer's pipeline state according
to the value specified by psc_type.
By setting the
parametric surface characteristics attribute's ASF to
PEXIndividual
(see PEXOCCSetIndividualASF),
you use the pipeline state's parametric surface
characteristics entry to apply aids when visualizing the
shape of parametric surfaces.
When you set the parametric surface characteristics
attribute's ASF to PEXBundled, the implementation
uses the parametric surface characteristics from the
interior bundle table.
PEXlib defines the following
parametric surface characteristics
(characteristics):
- PEXPSCNone -
- does not apply any special aids when visualizing the shape
of a parametric surface.
No data is required for this type. (5.0)
- PEXPSCImpDep -
- applies an implementation-dependent aid when visualizing
the shade of a parametric surface.
Back-facing portions of the surface are not distinguished.
The appearance of the representation is controlled by the
appropriate set of primitive attributes for the
representation.
It is implementation-dependent how the representation
interacts with any interior rendering indicated by the
interior attributes.
No data is defined for this type, therefore
characteristics is ignored. (5.0)
- PEXPSCIsoCurves -
- draws isoparametric curves on the surface.
The data pointed to by characteristics contains the
number of curves to draw in each of the parameter dimensions
and their placement.
If the placement is Uniform, then the specified number of
curves are evenly spaced between the parameter limits of the
surface; curves are also drawn at the parameter limits.
If the placement is NonUniform, then the specified number of
curves are evenly spaced between each pair of knots; curves
are also drawn at the knots.
In both cases, only the portions of the isoparametric curves
are drawn that are within the interior of the surface as
defined by any trimming curves. (5.0)
Back-facing portions of the surface are not distinguished.
The tessellation and appearance of the isoparametric curves
are controlled by the surface approximation criteria and the
polyline attributes, respectively.
The isoparametric curves are drawn in addition to any
interior rendering indicated by the interior style or back
interior style attributes.
Isoparametric curves have higher visual priority than the
primitive's filled or hollow interiors, but lower priority
than the primitive's edges.
If the placement is not
Uniform or NonUniform, then the implementation issues a
BadPEXOutputCommand error.
- PEXPSCMCLevelCurves -
- Draws level curves on the surface.
The curves correspond to the intersections of the surface
and a finite set of places perpendicular to a modeling
coordinate direction vector.
The positions of the planes are specified by a sequence of
intersecting points along an infinite line defined by a
modeling coordinate origin point, P0,
and a direction vector,
The ti
are a sequence of parameters specifying the
intersection points.
They are in the range:
The Pi are the intersection points of the
perpendicular planes with the infinite line.
P0 is a specified origin point in
modeling clipping coordinates, and
is the specified direction vector in modeling coordinates.
The ith plane is perpendicular to
the direction vector,
,
and intersects the
infinite line at point Pi.
Back-facing portions of the surface are not distinguished.
The tessellation and appearance of the level curves are
controlled by the surface approximation criteria and the
polyline attributes, respectively.
The curves are drawn in addition to any interior rendering
indicated by the interior style or back-facing interior style
attributes.
Level curves have higher visual priority than a primitive's
filled or hollowed interiors, but lower priority than its
edges. (5.0)
If you specify a direction vector
length of zero, then the implementation issues a
BadPEXOutputCommand error.
- PEXPSCWCLevelCurves -
draws level curves on the surface.
This type is identical to type PEXPSCMCLevelCurves
except that the origin point, P0, and
the direction vector,
,
are defined in world
coordinates instead of modeling coordinates. (5.0)
If the implementation does not support the specified
parametric surface characteristics type (psc_type),
then the parametric surface characteristics type defaults to
PEXPSCNone.
Inquire the supported values for the parametric surface
characteristic types by invoking the
PEXGetEnumTypeInfo function.
This function is a member of the
parametric surface
attribute set.
- BadPEXOutputCommand
- The output command contains an invalid value.
- BadPEXRenderer
- The specified renderer resource identifier is invalid.
- BadPEXStructure
- The specified structure resource identifier is invalid.
For an overview and for a list of output attribute functions, see
Output Attribute Functions.