SoNormalBundle.h

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/*=======================================================================
** Author      : Paul S. Strauss (MMM yyyy)
**=======================================================================*/
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**=======================================================================*/
/*=======================================================================
** Modified by : VSG (MMM YYYY)
**=======================================================================*/
 
 
#ifndef  _SO_NORMAL_BUNDLE
#define  _SO_NORMAL_BUNDLE
 
#include <Inventor/bundles/SoBundle.h>
#include <Inventor/elements/SoNormalElement.h>
#include <Inventor/elements/SoNormalBindingElement.h>
#include <Inventor/misc/SoNormalGenerator.h>
 
class SoNormalCache;

//
//  Class: SoNormalBundle
//
//  Bundle that allows shapes to deal with normals and normal bindings
//  more easily. This class provides a fairly simple interface to
//  normal handling, including normal generation.
//
//  This class can be used during either rendering or primitive
//  generation. For primitive generation, the get() method can be used
//  to access normals. For GL rendering, the send() method can be used
//  to send normals to GL.
//
 
{
 
 public:
 
  // Constructor - takes the action the bundle is used for and a
  // flag to indicate whether the bundle is being used for
  // rendering. If this is TRUE, the bundle can be used to send
  // normals to GL.
  SoNormalBundle( SoAction *action, SbBool forRendering );
 
  // Destructor
  virtual ~SoNormalBundle();
 
  // Returns TRUE if normals need to be generated.
  SbBool              shouldGenerate(int numNeeded);
 
  // Initializes generation in the case where shouldGenerate() is
  // not called. (shouldGenerate() does this automatically).
  void                initGenerator(int initialNum = 100);

  //
  // If shouldGenerate() returns TRUE, these methods can be used by
  // shapes to specify the geometry to generate normals for. They
  // are front-ends to methods on the SoNormalGenerator class:
  //
 
  // Send a polygon's worth of vertices. Begin a polygon, send as
  // many vertices as you want, and then end the polygon.
  void                beginPolygon()
    { generator->beginPolygon(); }
  void                polygonVertex(const SbVec3f &point)
    { generator->polygonVertex(point); }
  void                endPolygon()
    { generator->endPolygon(); }
 
  // Send a triangle
  void                triangle(const SbVec3f &p1,
                               const SbVec3f &p2,
                               const SbVec3f &p3)
    { generator->triangle(p1, p2, p3); }
 
  // See SoNormalGenerator for details.
  void setupIndexedVertexArray(const SbVec3f* pointArray)
  { generator->setupIndexedVertexArray(pointArray); }
  void polygonVertex(const int32_t index)
    { generator->polygonVertex(index); }
  void triangle(const int32_t index1,const int32_t index2,const int32_t index3)
    { generator->triangle(index1,index2,index3); }
  void setupIndexedConnectivity(const int32_t* connectivityArray)
    { generator->setupIndexedConnectivity(connectivityArray); }
  void setupApproxShapeSize(const int32_t numVert,const int32_t numFace)
  { generator->setupApproxShapeSize(numVert,numFace); }
 
  // Calculates the normals once all vertices have been sent. The
  // normals are stored by the bundle so the caller does not have to
  // deal with them directly.  The startIndex argument specifies the
  // index at which the generated normals will begin-- it can be
  // used by shapes that allow the coordinates and normals to be
  // offset (non-indexed shapes).  If addToState is TRUE, the
  // state will be pushed, the normals will be added to the
  // state; otherwise, you can just use
  // getGeneratedNormals/getNumGeneratedNormals to get the generated
  // normals.
  //
  // The normal bundle DOES NOT FREE the generated normals!  It is
  // expected that normals will be added to a normal cache, and the
  // normal cache will free the normals.
  //
  void                generate(int startIndex = 0,
                               SbBool addToState=TRUE);
 
  // Returns the generated normals.
  const SbVec3f *     getGeneratedNormals() const
    { return generator->getNormals(); }
  int                 getNumGeneratedNormals() const
    { return generator->getNumNormals(); }
  SoNormalBindingElement::Binding getNormalBinding() const
  {
    if (m_isIndexedNormal)
      return SoNormalBindingElement::PER_VERTEX_INDEXED;
    else
      return SoNormalBindingElement::PER_VERTEX;
  }
 
 
  // This allows shapes that generate their own normals (for
  // efficiency) to store the resulting normals in the state. The
  // bundle takes care of pushing/popping the state.
  // Note:  This method only adds the normals to the state, it does
  // NOT store a pointer to them (so you cannot call the
  // getGenerated() routines)
  void set(
    int32_t numNormals,
    const SbVec3f *normals,
    const SoNormalBindingElement::Binding binding /*= SoNormalBindingElement::PER_VERTEX */,
    const int startIndex = 0
    );
 
  // to set the SoNormalBundle from a SoNormalCache
  void set(SoNormalCache* nc);
 
  // Returns indexed normal. This can be used for primitive
  // generation or during rendering
  const SbVec3f& get(int index) const
  { return normElt->getNum() != 0 ? normElt->get(index - m_startIndex) : s_zVers; }
 
  // Sends indexed normal to the GL, for use only during GL rendering
  virtual void send(int index) const;
  
  // return the number of normal crack
  // -1 if the info is not available.
  int numNormalCrack() const
  { return generator->numNormalCrack(); }
 
  int getStartIndex() const
  { return m_startIndex; }
 
 private:
 
  SoNormalGenerator   *generator;     // Normal generator
 
 private:
  // Normal elements:
  const SoNormalElement       *normElt;
  const SoNormalElement     *GLNormElt;
 
  SbBool                                  isRendering;    // Bundle being used for rendering
  SbBool                                  pushedState;    // We pushed state to set normals
  SoNode                                  *currentNode;   // Node that created the bundle
  bool                                    m_isIndexedNormal;
  static const SbVec3f                    s_zVers;
  int                                     m_startIndex;   // this the offset used in indexing the normals WITHOUT allocating useless memory
  bool                                    m_normSetOrGen;
 
};
 
#endif /* _SO_NORMAL_BUNDLE */