SoTCBCurve Class Reference

The SoTCBCurve class is a node for representing smooth curves. More...

#include <Inventor/nodes/SoTCBCurve.h>

Inheritance diagram for SoTCBCurve:

Public Member Functions
	SoTCBCurve (void)
int	getLinesPerSegment (void)

Static Public Member Functions
static void	initClass (void)
static void	TCB (const SbVec3f *vec, const SoMFTime &timestamp, const int numControlpoints, const SbTime time, SbVec3f &res)

Public Attributes
SoSFInt32	numControlpoints
SoMFTime	timestamp

Protected Member Functions
virtual	~SoTCBCurve ()
virtual void	computeBBox (SoAction *action, SbBox3f &box, SbVec3f &center)
virtual void	generatePrimitives (SoAction *action)
virtual void	GLRender (SoGLRenderAction *action)

Detailed Description

The SoTCBCurve class is a node for representing smooth curves.

The TCB-type curve guarantees that all control points are touched by the curve. If no timestamps are specified, all time intervals are set to equal length. Coordinates are read from the state.

Note that the list of timestamps must be sorted in increasing order.

Example usage:

#include <Inventor/Qt/SoQt.h>
#include <Inventor/Qt/viewers/SoQtExaminerViewer.h>
#include <SmallChange/nodes/SoTCBCurve.h>
#include <Inventor/nodes/SoCoordinate3.h>
#include <Inventor/nodes/SoSeparator.h>
 
int
main(int argc, char* argv[])
{
  QWidget * mainwin = SoQt::init(argv[0]);
 
  SoTCBCurve::initClass();
 
  SoSeparator * root = new SoSeparator;
  root->ref();
 
  const SbVec3f coordset[] = {
    SbVec3f(0, 0, 0),
    SbVec3f(1, 1, 0),
    SbVec3f(2, 0, 0),
    SbVec3f(3, -1, 0),
    SbVec3f(4, 0, 0)
  };
 
  SoCoordinate3 * coords = new SoCoordinate3;
  coords->point.setValues(0, sizeof(coordset) / sizeof(coordset[0]), coordset);
 
  root->addChild(coords);
 
  SoTCBCurve * curve = new SoTCBCurve;
  curve->numControlpoints = coords->point.getNum();
 
  // XXX this should really have been unnecessary, but due to a bug in
  // SoTCBCurve vs spec... XXX
#if 1
  for (int i=0; i < coords->point.getNum(); i++) {
    curve->timestamp.set1Value(i, SbTime((double)i));
  }
#endif
 
  root->addChild(curve);
 
  SoQtExaminerViewer * viewer = new SoQtExaminerViewer(mainwin);
  viewer->setSceneGraph(root);
 
  SoQt::show(mainwin);
  SoQt::mainLoop();
 
  delete viewer;
  root->unref();
 
  return 0;
}

Constructor & Destructor Documentation

SoTCBCurve()

SoTCBCurve::SoTCBCurve

(

void

)

Constructor.

~SoTCBCurve()

SoTCBCurve::~SoTCBCurve ( )

protectedvirtual

Destructor.

Member Function Documentation

getLinesPerSegment()

int SoTCBCurve::getLinesPerSegment

(

void

)

Returns an integer with the number of lines per segment rendered at the previous pass.

TCB()

void SoTCBCurve::TCB ( const SbVec3f * vec, const SoMFTime & timestamp, const int numControlpoints, const SbTime time, SbVec3f & res )

static

Static function to interpolate values along a curve.

This function is based on the Lightwave SDK (ftp.newtek.com) and calculates a TCB-type curve. Code for handling continuity / tension / bias is removed (values = 1). Quite ironic as this is how the curve got its name. :) The timestamp table must be sorted in increasing order. Time values specified outside the range of timestamps will be clipped to the nearest value.

This function is totally independent of the rest of the class, and may be used for general curve calculations.

Member Data Documentation

numControlpoints

SoSFInt32 SoTCBCurve::numControlpoints

Number of control points to use in this NURBS curve.

timestamp

SoMFTime SoTCBCurve::timestamp

The timestamps for the curve. This table must contain either 0 elements or exactly numControlpoints elements. Nothing in between. This list must be sorted in increasing order.

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

• SoTCBCurve.h
• SoTCBCurve.cpp