.TH "SoIndexedFaceSet" 3 "Thu May 29 2014" "Version 4.0.0a" "Coin" \" -*- nroff -*-
.ad l
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.SH NAME
SoIndexedFaceSet \- 
.PP
The \fBSoIndexedFaceSet\fP class is used to handle generic indexed facesets\&.
.PP
Faces are specified using the coordIndex field\&. Each face must be terminated by a negative (-1) index\&. Coordinates, normals, materials and texture coordinates from the current state (or from the vertexProperty node if set), can be indexed to create triangles, quads or polygons\&.  

.SH SYNOPSIS
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.PP
.PP
\fC#include <Inventor/nodes/SoIndexedFaceSet\&.h>\fP
.PP
Inherits \fBSoIndexedShape\fP\&.
.SS "Public Member Functions"

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.ti -1c
.RI "virtual \fBSoType\fP \fBgetTypeId\fP (void) const "
.br
.RI "\fIReturns the type identification of an object derived from a class inheriting \fBSoBase\fP\&. This is used for run-time type checking and 'downward' casting\&. \fP"
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.RI "\fBSoIndexedFaceSet\fP (void)"
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.RI "virtual void \fBGLRender\fP (\fBSoGLRenderAction\fP *action)"
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.RI "virtual void \fBgetPrimitiveCount\fP (\fBSoGetPrimitiveCountAction\fP *action)"
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.RI "virtual SbBool \fBgenerateDefaultNormals\fP (\fBSoState\fP *state, \fBSoNormalBundle\fP *bundle)"
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.RI "virtual SbBool \fBgenerateDefaultNormals\fP (\fBSoState\fP *state, \fBSoNormalCache\fP *cache)"
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.in -1c
.SS "Static Public Member Functions"

.in +1c
.ti -1c
.RI "static \fBSoType\fP \fBgetClassTypeId\fP (void)"
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.RI "static void \fBinitClass\fP (void)"
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.SS "Protected Member Functions"

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.ti -1c
.RI "virtual const \fBSoFieldData\fP * \fBgetFieldData\fP (void) const "
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.RI "virtual \fB~SoIndexedFaceSet\fP ()"
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.RI "virtual void \fBgeneratePrimitives\fP (\fBSoAction\fP *action)"
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.SS "Static Protected Member Functions"

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.RI "static const \fBSoFieldData\fP ** \fBgetFieldDataPtr\fP (void)"
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.SS "Additional Inherited Members"
.SH "Detailed Description"
.PP 
The \fBSoIndexedFaceSet\fP class is used to handle generic indexed facesets\&.
.PP
Faces are specified using the coordIndex field\&. Each face must be terminated by a negative (-1) index\&. Coordinates, normals, materials and texture coordinates from the current state (or from the vertexProperty node if set), can be indexed to create triangles, quads or polygons\&. 

Here's a usage example of just about the simplest possible use of this node, to show a single polygon face:
.PP
.PP
.nf
#Inventor V2.1 ascii

Separator {
   Coordinate3 {
      point [ 0 0 0, 1 0 0, 1 1 0 ]
   }
   IndexedFaceSet {
      coordIndex [ 0, 1, 2, -1 ]
   }
}
.fi
.PP
.PP
Binding PER_VERTEX_INDEXED, PER_VERTEX, PER_FACE_INDEXED, PER_FACE or OVERALL can be set for material, and normals\&. The default material binding is OVERALL\&. The default normal binding is PER_VERTEX_INDEXED\&. When PER_VERTEX_INDEXED binding is used and the corresponding materialIndex, normalIndex, texCoordIndex field is empty, the coordIndex field will be used to index material, normal or texture coordinate\&. If you do specify indices for material, normals or texture coordinates for PER_VERTEX_INDEXED binding, make sure your index array matches the coordIndex array: there should be a -1 wherever there is a -1 in the coordIndex field\&. This is done to make this node more easily readable for humans\&.
.PP
A fairly common request when rendering facesets is how to display a set of faces with different colors on the backside versus the frontside\&. There is not \fIdirect\fP support for this in the API, but it can easily be implemented by duplicating all faces in both the \fBSoShapeHints::COUNTERCLOCKWISE\fP and the \fBSoShapeHints::CLOCKWISE\fP order\&. Here is a simple usage example, showing the technique for a single polygon, using two \fBSoFaceSet\fP nodes for rendering the same polygon from both sides:
.PP
.PP
.nf
#Inventor V2.1 ascii

Separator {
   Coordinate3 { point [ 0 0 0, 1 0 0, 1 1 0 ] }

   Separator {
      Material { diffuseColor [ 1 1 0 ] }
      ShapeHints {
         vertexOrdering COUNTERCLOCKWISE
         shapeType SOLID
      }
      FaceSet { numVertices [ 3 ] }
   }

   Separator {
      Material { diffuseColor [ 1 0 0 ] }
      ShapeHints {
         vertexOrdering CLOCKWISE
         shapeType SOLID
      }
      FaceSet { numVertices [ 3 ] }
   }
}
.fi
.PP
.PP
The same effect can also be done in the following manner, using an \fBSoIndexedFaceSet\fP to explicitly render the polygon coordinates in both directions (clockwise and counterclockwise):
.PP
.PP
.nf
#Inventor V2.1 ascii

Separator {
   Coordinate3 { point [ 0 0 0, 1 0 0, 1 1 0 ] }

   Material { diffuseColor [ 1 0 0, 1 1 0 ] }
   MaterialBinding { value PER_FACE_INDEXED }

   ShapeHints {
      vertexOrdering COUNTERCLOCKWISE
      shapeType SOLID
   }

   IndexedFaceSet {
      coordIndex [ 0, 1, 2, -1, 2, 1, 0, -1 ]
      materialIndex [ 0, 1 ]
   }
}
.fi
.PP
.PP
Another rather rare issue that might be interesting to know about is that to render polygons with concave borders, you should set up an \fBSoShapeHints\fP node with \fBSoShapeHints::faceType\fP set to \fBSoShapeHints::UNKNOWN_FACE_TYPE\fP in the scene graph before the \fBSoIndexedFaceSet\fP (or \fBSoFaceSet\fP) node\&. This needs to be done to force the rendering code to tessellate the polygons properly to triangles before sending it off to OpenGL\&. Without it, the polygons will be sent as-is to OpenGL, and the OpenGL implementation's tessellator is often not able to tessellate properly\&. Here is an example which usually fails without the \fBSoShapeHints\fP node (try commenting it out, and see what happens):
.PP
.PP
.nf
#Inventor V2.1 ascii

ShapeHints { faceType UNKNOWN_FACE_TYPE }

Coordinate3
{
        point [ 2 0 0,
                1 0 0,
                1 1 0,
                0 1 0,
                0 2 0,
                1 2 0,
                2 2 0,
                2 1 0 ]
}

FaceSet {}
.fi
.PP
.PP
\fBFILE FORMAT/DEFAULTS:\fP 
.PP
.nf
IndexedFaceSet {
    vertexProperty NULL
    coordIndex 0
    materialIndex -1
    normalIndex -1
    textureCoordIndex -1
}

.fi
.PP
.PP
\fBSee also:\fP
.RS 4
\fBSoFaceSet\fP, \fBSoIndexedTriangleStripSet\fP 
.RE
.PP

.SH "Constructor & Destructor Documentation"
.PP 
.SS "SoIndexedFaceSet::SoIndexedFaceSet (void)"
Constructor\&. 
.SS "SoIndexedFaceSet::~SoIndexedFaceSet ()\fC [protected]\fP, \fC [virtual]\fP"
Destructor\&. 
.SH "Member Function Documentation"
.PP 
.SS "\fBSoType\fP SoIndexedFaceSet::getTypeId (void) const\fC [virtual]\fP"

.PP
Returns the type identification of an object derived from a class inheriting \fBSoBase\fP\&. This is used for run-time type checking and 'downward' casting\&. Usage example:
.PP
.PP
.nf
void foo(SoNode * node)
{
  if (node->getTypeId() == SoFile::getClassTypeId()) {
    SoFile * filenode = (SoFile *)node;  // safe downward cast, knows the type
  }
}
.fi
.PP
.PP
For application programmers wanting to extend the library with new nodes, engines, nodekits, draggers or others: this method needs to be overridden in \fIall\fP subclasses\&. This is typically done as part of setting up the full type system for extension classes, which is usually accomplished by using the pre-defined macros available through for instance \fBInventor/nodes/SoSubNode\&.h\fP (SO_NODE_INIT_CLASS and SO_NODE_CONSTRUCTOR for node classes), Inventor/engines/SoSubEngine\&.h (for engine classes) and so on\&.
.PP
For more information on writing Coin extensions, see the class documentation of the toplevel superclasses for the various class groups\&. 
.PP
Reimplemented from \fBSoIndexedShape\fP\&.
.SS "const \fBSoFieldData\fP * SoIndexedFaceSet::getFieldData (void) const\fC [protected]\fP, \fC [virtual]\fP"
Returns a pointer to the class-wide field data storage object for this instance\&. If no fields are present, returns \fCNULL\fP\&. 
.PP
Reimplemented from \fBSoIndexedShape\fP\&.
.SS "void SoIndexedFaceSet::GLRender (\fBSoGLRenderAction\fP *action)\fC [virtual]\fP"
Action method for the \fBSoGLRenderAction\fP\&.
.PP
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\&. 
.PP
Reimplemented from \fBSoShape\fP\&.
.SS "void SoIndexedFaceSet::getPrimitiveCount (\fBSoGetPrimitiveCountAction\fP *action)\fC [virtual]\fP"
Action method for the \fBSoGetPrimitiveCountAction\fP\&.
.PP
Calculates the number of triangle, line segment and point primitives for the node and adds these to the counters of the \fIaction\fP\&.
.PP
Nodes influencing how geometry nodes calculates their primitive count also overrides this method to change the relevant state variables\&. 
.PP
Reimplemented from \fBSoShape\fP\&.
.SS "SbBool SoIndexedFaceSet::generateDefaultNormals (\fBSoState\fP *state, \fBSoNormalBundle\fP *bundle)\fC [virtual]\fP"
\fIThis API member is considered internal to the library, as it is not likely to be of interest to the application programmer\&.\fP
.PP
Subclasses should override this method to generate default normals using the \fBSoNormalBundle\fP class\&. \fCTRUE\fP should be returned if normals were generated, \fCFALSE\fP otherwise\&.
.PP
Default method returns \fCFALSE\fP\&.
.PP
This function is an extension for Coin, and it is not available in the original SGI Open Inventor v2\&.1 API\&. 
.PP
Reimplemented from \fBSoVertexShape\fP\&.
.SS "SbBool SoIndexedFaceSet::generateDefaultNormals (\fBSoState\fP *state, \fBSoNormalCache\fP *cache)\fC [virtual]\fP"
\fIThis API member is considered internal to the library, as it is not likely to be of interest to the application programmer\&.\fP
.PP
Subclasses should override this method to generate default normals using the \fBSoNormalCache\fP class\&. This is more effective than using \fBSoNormalGenerator\fP\&. Return \fCTRUE\fP if normals were generated, \fCFALSE\fP otherwise\&.
.PP
Default method just returns \fCFALSE\fP\&.
.PP
This function is an extension for Coin, and it is not available in the original SGI Open Inventor v2\&.1 API\&. 
.PP
Reimplemented from \fBSoVertexShape\fP\&.
.SS "void SoIndexedFaceSet::generatePrimitives (\fBSoAction\fP *action)\fC [protected]\fP, \fC [virtual]\fP"
The method implements action behavior for shape nodes for \fBSoCallbackAction\fP\&. It is invoked from \fBSoShape::callback()\fP\&. (Subclasses should \fInot\fP override \fBSoNode::callback()\fP\&.)
.PP
The subclass implementations uses the convenience methods \fBSoShape::beginShape()\fP, \fBSoShape::shapeVertex()\fP, and \fBSoShape::endShape()\fP, with \fBSoDetail\fP instances, to pass the primitives making up the shape back to the caller\&. 
.PP
Implements \fBSoShape\fP\&.

.SH "Author"
.PP 
Generated automatically by Doxygen for Coin from the source code\&.