Vrml_ShapeHints Class Reference

defines a ShapeHints node of VRML specifying properties of geometry and its appearance. The ShapeHints node indicates that IndexedFaceSets are solid, contain ordered vertices, or contain convex faces. These hints allow VRML implementations 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, an implementation may turn on backface culling and turn off two-sided lighting. To ensure that an IndexedFaceSet can be viewed from either direction, set shapeType to be UNKNOWN_SHAPE_TYPE. If you know that your shapes are closed and will alwsys be viewed from the outside, set vertexOrdering to be either CLOCKWISE or COUNTERCLOCKWISE (depending on how you built your object), and set shapeType to be SOLID. Placing this near the top of your VRML file will allow the scene to be rendered much faster. The ShapeHints node also affects how default normals are generated. When an IndexedFaceSet has to generate default normals, it uses the creaseAngle field to determine which edges should be smoothly 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 (the default value) 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. More...

#include <Vrml_ShapeHints.hxx>

Public Member Functions
	Vrml_ShapeHints (const Vrml_VertexOrdering aVertexOrdering=Vrml_UNKNOWN_ORDERING, const Vrml_ShapeType aShapeType=Vrml_UNKNOWN_SHAPE_TYPE, const Vrml_FaceType aFaceType=Vrml_CONVEX, const Standard_Real aAngle=0.5)
void	SetVertexOrdering (const Vrml_VertexOrdering aVertexOrdering)
Vrml_VertexOrdering	VertexOrdering () const
void	SetShapeType (const Vrml_ShapeType aShapeType)
Vrml_ShapeType	ShapeType () const
void	SetFaceType (const Vrml_FaceType aFaceType)
Vrml_FaceType	FaceType () const
void	SetAngle (const Standard_Real aAngle)
Standard_Real	Angle () const
Standard_OStream &	Print (Standard_OStream &anOStream) const

Detailed Description

defines a ShapeHints node of VRML specifying properties of geometry and its appearance. The ShapeHints node indicates that IndexedFaceSets are solid, contain ordered vertices, or contain convex faces. These hints allow VRML implementations 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, an implementation may turn on backface culling and turn off two-sided lighting. To ensure that an IndexedFaceSet can be viewed from either direction, set shapeType to be UNKNOWN_SHAPE_TYPE. If you know that your shapes are closed and will alwsys be viewed from the outside, set vertexOrdering to be either CLOCKWISE or COUNTERCLOCKWISE (depending on how you built your object), and set shapeType to be SOLID. Placing this near the top of your VRML file will allow the scene to be rendered much faster. The ShapeHints node also affects how default normals are generated. When an IndexedFaceSet has to generate default normals, it uses the creaseAngle field to determine which edges should be smoothly 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 (the default value) 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.

Constructor & Destructor Documentation

Vrml_ShapeHints()

Vrml_ShapeHints::Vrml_ShapeHints	(	const Vrml_VertexOrdering	aVertexOrdering = Vrml_UNKNOWN_ORDERING,
		const Vrml_ShapeType	aShapeType = Vrml_UNKNOWN_SHAPE_TYPE,
		const Vrml_FaceType	aFaceType = Vrml_CONVEX,
		const Standard_Real	aAngle = 0.5
	)

Member Function Documentation

Angle()

Standard_Real Vrml_ShapeHints::Angle

(

)

const

FaceType()

Vrml_FaceType Vrml_ShapeHints::FaceType

(

)

const

Print()

Standard_OStream& Vrml_ShapeHints::Print

(

Standard_OStream &

anOStream

)

const

SetAngle()

void Vrml_ShapeHints::SetAngle

(

const Standard_Real

aAngle

)

SetFaceType()

void Vrml_ShapeHints::SetFaceType

(

const Vrml_FaceType

aFaceType

)

SetShapeType()

void Vrml_ShapeHints::SetShapeType

(

const Vrml_ShapeType

aShapeType

)

SetVertexOrdering()

void Vrml_ShapeHints::SetVertexOrdering

(

const Vrml_VertexOrdering

aVertexOrdering

)

ShapeType()

Vrml_ShapeType Vrml_ShapeHints::ShapeType

(

)

const

VertexOrdering()

Vrml_VertexOrdering Vrml_ShapeHints::VertexOrdering

(

)

const

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The documentation for this class was generated from the following file:

• Vrml_ShapeHints.hxx