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SoVRMLIndexedFaceSet Class Reference
[VRML97 classes]

#include <Inventor/VRMLnodes/SoVRMLIndexedFaceSet.h>

Inheritance diagram for SoVRMLIndexedFaceSet:

SoVRMLIndexedShape SoVRMLVertexShape SoVRMLGeometry SoShape SoNode SoFieldContainer SoBase List of all members.

Detailed Description

The SoVRMLIndexedFaceSet class is used for representing a generic 3D shape.

The detailed class documentation is taken verbatim from the VRML97 standard (ISO/IEC 14772-1:1997). It is copyright The Web3D Consortium, and is used by permission of the Consortium:

IndexedFaceSet { eventIn MFInt32 set_colorIndex eventIn MFInt32 set_coordIndex eventIn MFInt32 set_normalIndex eventIn MFInt32 set_texCoordIndex exposedField SFNode color NULL exposedField SFNode coord NULL exposedField SFNode normal NULL exposedField SFNode texCoord NULL field SFBool ccw TRUE field MFInt32 colorIndex [] # [-1,) field SFBool colorPerVertex TRUE field SFBool convex TRUE field MFInt32 coordIndex [] # [-1,) field SFFloat creaseAngle 0 # [0,) field MFInt32 normalIndex [] # [-1,) field SFBool normalPerVertex TRUE field SFBool solid TRUE field MFInt32 texCoordIndex [] # [-1,) }

The IndexedFaceSet node represents a 3D shape formed by constructing faces (polygons) from vertices listed in the coord field. The coord field contains a Coordinate node that defines the 3D vertices referenced by the coordIndex field. IndexedFaceSet uses the indices in its coordIndex field to specify the polygonal faces by indexing into the coordinates in the Coordinate node. An index of "-1" indicates that the current face has ended and the next one begins. The last face may be (but does not have to be) followed by a "-1" index. If the greatest index in the coordIndex field is N, the Coordinate node shall contain N+1 coordinates (indexed as 0 to N). Each face of the IndexedFaceSet shall have:

Otherwise, The results are undefined.

The IndexedFaceSet node is specified in the local coordinate system and is affected by the transformations of its ancestors.

Descriptions of the coord, normal, and texCoord fields are provided in the SoVRMLCoordinate, SoVRMLNormal, and SoVRMLTextureCoordinate nodes, respectively.

Details on lighting equations and the interaction between color field, normal field, textures, materials, and geometries are provided in 4.14, Lighting model.

If the color field is not NULL, it shall contain a Color node whose colours are applied to the vertices or faces of the IndexedFaceSet as follows:

If the color field is NULL, the geometry shall be rendered normally using the Material and texture defined in the Appearance node (see 4.14, Lighting model, for details http://www.web3d.org/technicalinfo/specifications/vrml97/part1/concepts.html#4.6.5).

If the normal field is not NULL, it shall contain a Normal node whose normals are applied to the vertices or faces of the IndexedFaceSet in a manner exactly equivalent to that described above for applying colours to vertices/faces (where normalPerVertex corresponds to colorPerVertex and normalIndex corresponds to colorIndex). If the normal field is NULL, the browser shall automatically generate normals, using creaseAngle to determine if and how normals are smoothed across shared vertices (see 4.6.3.5, Crease angle field).

If the texCoord field is not NULL, it shall contain a TextureCoordinate node. The texture coordinates in that node are applied to the vertices of the IndexedFaceSet as follows: If the texCoordIndex field is not empty, then it is used to choose texture coordinates for each vertex of the IndexedFaceSet in exactly the same manner that the coordIndex field is used to choose coordinates for each vertex from the Coordinate node. The texCoordIndex field shall contain at least as many indices as the coordIndex field, and shall contain end-of-face markers (-1) in exactly the same places as the coordIndex field. If the greatest index in the texCoordIndex field is N, then there shall be N+1 texture coordinates in the TextureCoordinate node.

If the texCoordIndex field is empty, then the coordIndex array is used to choose texture coordinates from the TextureCoordinate node. If the greatest index in the coordIndex field is N, then there shall be N+1 texture coordinates in the TextureCoordinate node. If the texCoord field is NULL, a default texture coordinate mapping is calculated using the local coordinate system bounding box of the shape. The longest dimension of the bounding box defines the S coordinates, and the next longest defines the T coordinates. If two or all three dimensions of the bounding box are equal, ties shall be broken by choosing the X, Y, or Z dimension in that order of preference. The value of the S coordinate ranges from 0 to 1, from one end of the bounding box to the other. The T coordinate ranges between 0 and the ratio of the second greatest dimension of the bounding box to the greatest dimension. Figure 6.10 illustrates the default texture coordinates for a simple box shaped IndexedFaceSet with an X dimension twice as large as the Z dimension and four times as large as the Y dimension. Figure 6.11 illustrates the original texture image used on the IndexedFaceSet used in Figure 6.10.

IFStexture.gif
Figure 6.10

IFStexture2.gif
Figure 6.11

Subclause 4.6.3, Shapes and geometry (<http://www.web3d.org/technicalinfo/specifications/vrml97/part1/concepts.html#4.6.5>), provides a description of the ccw, solid, convex, and creaseAngle fields.


Public Member Functions

 SoVRMLIndexedFaceSet (void)
virtual void GLRender (SoGLRenderAction *action)
virtual void getPrimitiveCount (SoGetPrimitiveCountAction *action)
virtual SbBool generateDefaultNormals (SoState *s, SoNormalBundle *nb)
virtual SbBool generateDefaultNormals (SoState *state, SoNormalCache *nc)

Static Public Member Functions

void initClass (void)

Public Attributes

SoSFBool ccw
SoSFBool solid
SoSFBool convex
SoSFFloat creaseAngle

Protected Member Functions

virtual ~SoVRMLIndexedFaceSet ()
virtual void generatePrimitives (SoAction *action)


Constructor & Destructor Documentation

SoVRMLIndexedFaceSet::SoVRMLIndexedFaceSet void   ) 
 

Constructor.

SoVRMLIndexedFaceSet::~SoVRMLIndexedFaceSet  )  [protected, virtual]
 

Destructor.


Member Function Documentation

void SoVRMLIndexedFaceSet::initClass void   )  [static]
 

Sets up initialization for data common to all instances of this class, like submitting necessary information to the Coin type system.

Reimplemented from SoVRMLIndexedShape.

void SoVRMLIndexedFaceSet::GLRender SoGLRenderAction action  )  [virtual]
 

Action method for the SoGLRenderAction.

This is called during rendering traversals. Nodes influencing the rendering state in any way or who wants to throw geometry primitives at OpenGL overrides this method.

Reimplemented from SoVRMLVertexShape.

void SoVRMLIndexedFaceSet::getPrimitiveCount SoGetPrimitiveCountAction action  )  [virtual]
 

Action method for the SoGetPrimitiveCountAction.

Calculates the number of triangle, line segment and point primitives for the node and adds these to the counters of the action.

Nodes influencing how geometry nodes calculates their primitive count also overrides this method to change the relevant state variables.

Reimplemented from SoShape.

SbBool SoVRMLIndexedFaceSet::generateDefaultNormals SoState s,
SoNormalBundle *  nb
[virtual]
 

This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

Subclasses should override this method to generate default normals using the SoNormalBundle class. TRUE should be returned if normals were generated, FALSE otherwise.

Default method returns FALSE.

This function is an extension for Coin, and it is not available in the original SGI Open Inventor v2.1 API.

Reimplemented from SoVRMLVertexShape.

SbBool SoVRMLIndexedFaceSet::generateDefaultNormals SoState state,
SoNormalCache *  nc
[virtual]
 

This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

Subclasses should override this method to generate default normals using the SoNormalCache class. This is more effective than using SoNormalGenerator. Return TRUE if normals were generated, FALSE otherwise.

Default method just returns FALSE.

This function is an extension for Coin, and it is not available in the original SGI Open Inventor v2.1 API.

Reimplemented from SoVRMLVertexShape.

void SoVRMLIndexedFaceSet::generatePrimitives SoAction action  )  [protected, virtual]
 

The method implements action behavior for shape nodes for SoCallbackAction. It is invoked from SoShape::callback(). (Subclasses should not override SoNode::callback().)

The subclass implementations uses the convenience methods SoShape::beginShape(), SoShape::shapeVertex(), and SoShape::endShape(), with SoDetail instances, to pass the primitives making up the shape back to the caller.

Implements SoShape.


Member Data Documentation

SoSFBool SoVRMLIndexedFaceSet::ccw
 

Specifies if vertex ordering is counterclockwise. Default value is TRUE.

SoSFBool SoVRMLIndexedFaceSet::solid
 

Can be used to enable backface culling. Default value is TRUE.

SoSFBool SoVRMLIndexedFaceSet::convex
 

Specifies if all polygons are convex. Default value is TRUE.

SoSFFloat SoVRMLIndexedFaceSet::creaseAngle
 

Specifies the crease angle for the generated normals. Default value is 0.0.


The documentation for this class was generated from the following files:
Generated on Thu Apr 29 08:39:53 2004 for Coin by doxygen 1.3.6