trusty (3) SoShapeHints.3iv.gz
NAME
SoShapeHints — node that provides hints about shapes
INHERITS FROM
SoBase > SoFieldContainer > SoNode > SoShapeHints
SYNOPSIS
#include <Inventor/nodes/SoShapeHints.h>
enum VertexOrdering {
SoShapeHints::UNKNOWN_ORDERING
Ordering of vertices is unknown
SoShapeHints::CLOCKWISE Face vertices are ordered clockwise (from the outside)
SoShapeHints::COUNTERCLOCKWISE
Face vertices are ordered counterclockwise (from the outside)
}
enum ShapeType {
SoShapeHints::UNKNOWN_SHAPE_TYPE
Nothing is known about the shape
SoShapeHints::SOLID The shape encloses a volume
}
enum FaceType {
SoShapeHints::UNKNOWN_FACE_TYPE
Nothing is known about faces
SoShapeHints::CONVEX All faces are convex
}
Fields from class SoShapeHints:
SoSFEnum vertexOrdering
SoSFEnum shapeType
SoSFEnum faceType
SoSFFloat creaseAngle
Methods from class SoShapeHints:
SoShapeHints()
static SoType getClassTypeId()
Methods from class SoNode:
void setOverride(SbBool state)
SbBool isOverride() const
SoNode * copy(SbBool copyConnections = FALSE) const
virtual SbBool affectsState() const
static SoNode * getByName(const SbName &name)
static int getByName(const SbName &name, SoNodeList &list)
Methods from class SoFieldContainer:
void setToDefaults()
SbBool hasDefaultValues() const
SbBool fieldsAreEqual(const SoFieldContainer *fc) const
void copyFieldValues(const SoFieldContainer *fc, SbBool copyConnections = FALSE)
SbBool set(const char *fieldDataString)
void get(SbString &fieldDataString)
virtual int getFields(SoFieldList &resultList) const
virtual SoField * getField(const SbName &fieldName) const
SbBool getFieldName(const SoField *field, SbName &fieldName) const
SbBool isNotifyEnabled() const
SbBool enableNotify(SbBool flag)
Methods from class SoBase:
void ref()
void unref() const
void unrefNoDelete() const
void touch()
virtual SoType getTypeId() const
SbBool isOfType(SoType type) const
virtual void setName(const SbName &name)
virtual SbName getName() const
DESCRIPTION
By default, Inventor assumes very little about the shapes it renders. You can use the SoShapeHints node
to indicate that vertex-based shapes (those derived from SoVertexShape) are solid, contain ordered
vertices, or contain convex faces. For fastest rendering, specify SOLID, COUNTERCLOCKWISE, CONVEX shapes.
These hints allow Inventor to optimize certain rendering features. Optimizations that may be performed
include enabling back-face culling and disabling two-sided lighting. For example, if an object is solid
and has ordered vertices, Inventor turns on backface culling and turns off two-sided lighting. If the
object is not solid but has ordered vertices, it turns off backface culling and turns on two-sided
lighting. In all other cases, both backface culling and two-sided lighting are off.
The SoShapeHints node also affects how default normals are generated. When a node derived from
SoVertexShape has to generate default normals, it uses the creaseAngle field to determine which edges
should be smooth-shaded and which ones should have a sharp crease. The crease angle is the angle between
surface normals on adjacent polygons. For example, a crease angle of .5 radians means that an edge
between two adjacent polygonal faces will be smooth shaded if the normals to the two faces form an angle
that is less than .5 radians (about 30 degrees). Otherwise, it will be faceted. Normal generation is
fastest when the creaseAngle is 0 (the default), producing one normal per facet. A creaseAngle of pi
produces one averaged normal per vertex.
FIELDS
SoSFEnum vertexOrdering
Indicates how the vertices of faces are ordered. CLOCKWISE ordering means that the vertices of each
face form a clockwise loop around the face, when viewed from the outside (the side toward which the
normal points).
SoSFEnum shapeType
Indicates whether the shape is known to enclose a volume (SOLID) or not. If the inside (the side away
from the surface normal) of any part of the shape is visible, the shape is not solid.
SoSFEnum faceType
Indicates whether each face is convex. Because the penalty for non-convex faces is very steep (faces
must be triangulated expensively), the default assumes all faces are convex. Therefore, shapes with
concave faces may not be displayed correctly unless this hint is set to UNKNOWN_FACE_TYPE.
SoSFFloat creaseAngle
Indicates the minimum angle (in radians) between two adjacent face normals required to form a sharp
crease at the edge when default normals are computed and used.
METHODS
SoShapeHints()
Creates a shape hints node with default settings.
static SoType getClassTypeId()
Returns type identifier for this class.
ACTION BEHAVIOR
SoGLRenderAction, SoCallbackAction, SoRayPickAction, SoGetBoundingBoxAction
Sets the state to contain the hints; sets up optimizations based on the hints.
FILE FORMAT/DEFAULTS
ShapeHints {
vertexOrdering UNKNOWN_ORDERING
shapeType UNKNOWN_SHAPE_TYPE
faceType CONVEX
creaseAngle 0
}
SEE ALSO
SoVertexShape
SoShapeHints(3IV)()