NAME
SoVRMLIndexedFaceSet -
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:
SYNOPSIS
#include <Inventor/VRMLnodes/SoVRMLIndexedFaceSet.h>
Inherits SoVRMLIndexedShape.
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
static void initClass (void)
Public Attributes
SoSFBool ccw
SoSFBool solid
SoSFBool convex
SoSFFloat creaseAngle
Protected Member Functions
virtual ~SoVRMLIndexedFaceSet ()
virtual void generatePrimitives (SoAction *action)
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,)
}
.fi
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:
· at least three non-coincident vertices;
· vertices that define a planar polygon;
· vertices that define a non-self-intersecting polygon.
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 colorPerVertex is FALSE, colours are applied to each face, as follows:
· If the colorIndex field is not empty, then one colour is used for each face of the IndexedFaceSet. There shall be at least as many indices in the colorIndex field as there are faces in the IndexedFaceSet. If the greatest index in the colorIndex field is N, then there shall be N+1 colours in the Color node. The colorIndex field shall not contain any negative entries.
· If the colorIndex field is empty, then the colours in the Color node are applied to each face of the IndexedFaceSet in order. There shall be at least as many colours in the Color node as there are faces.
· If colorPerVertex is TRUE, colours are applied to each vertex, as follows:
· If the colorIndex field is not empty, then colours are applied to 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 colorIndex 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 colorIndex field is N, then there shall be N+1 colours in the Color node.
· If the colorIndex field is empty, then the coordIndex field is used to choose colours from the Color node. If the greatest index in the coordIndex field is N, then there shall be N+1 colours in the Color node.
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/x3d/specifications/vrml/ISO-IEC-14772-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.
Figure 6.10
Figure 6.11
Subclause 4.6.3, Shapes and geometry (<http://www.web3d.org/x3d/specifications/vrml/ISO-IEC-14772-VRML97/part1/concepts.html#4.6.5>), provides a description of the ccw, solid, convex, and creaseAngle fields.
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 * s,
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.
Author
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