The SoNurbsCurve class is a node for representing smooth curves.A general explanation of NURBS is beyond the scope of the Coin documentation. For detailed information, refer to the specialized literature on the topic (for example "An Introduction to NURBS: With Historical Perspective" by David F. Rogers). A basic overview of curve and surface rendering using NURBS can be found in chapter 8 of "The Inventor Mentor". More...

#include <Inventor/nodes/SoNurbsCurve.h>

Inheritance diagram for SoNurbsCurve:

Public Member Functions
virtual SoType	getTypeId (void) const
	Returns the type identification of an object derived from a class inheriting SoBase. This is used for run-time type checking and "downward" casting. More...

	SoNurbsCurve (void)

virtual void	GLRender (SoGLRenderAction *action)

virtual void	rayPick (SoRayPickAction *action)

virtual void	getPrimitiveCount (SoGetPrimitiveCountAction *action)

virtual void	getBoundingBox (SoGetBoundingBoxAction *action)

void	sendPrimitive (SoAction , SoPrimitiveVertex )

Public Member Functions inherited from SoShape
virtual SbBool	affectsState (void) const

virtual void	notify (SoNotList *nl)

virtual void	callback (SoCallbackAction *action)

const SoBoundingBoxCache *	getBoundingBoxCache (void) const

Public Member Functions inherited from SoNode
void	setOverride (const SbBool state)

SbBool	isOverride (void) const

void	setNodeType (const NodeType type)

NodeType	getNodeType (void) const

virtual SoNode *	copy (SbBool copyconnections=FALSE) const

virtual void	doAction (SoAction *action)

virtual void	GLRenderBelowPath (SoGLRenderAction *action)

virtual void	GLRenderInPath (SoGLRenderAction *action)

virtual void	GLRenderOffPath (SoGLRenderAction *action)

virtual void	getMatrix (SoGetMatrixAction *action)

virtual void	handleEvent (SoHandleEventAction *action)

virtual void	pick (SoPickAction *action)

virtual void	search (SoSearchAction *action)

virtual void	write (SoWriteAction *action)

virtual void	audioRender (SoAudioRenderAction *action)

virtual void	grabEventsSetup (void)

virtual void	grabEventsCleanup (void)

virtual void	startNotify (void)

uint32_t	getNodeId (void) const

virtual SoChildList *	getChildren (void) const

virtual void	writeInstance (SoOutput *out)

virtual SoNode *	addToCopyDict (void) const

virtual void	copyContents (const SoFieldContainer *from, SbBool copyconnections)

virtual SoFieldContainer *	copyThroughConnection (void) const

Public Member Functions inherited from SoFieldContainer
void	setToDefaults (void)

SbBool	hasDefaultValues (void) const

SbBool	fieldsAreEqual (const SoFieldContainer *container) const

void	copyFieldValues (const SoFieldContainer *container, SbBool copyconnections=FALSE)

SbBool	set (const char *const fielddata)

void	get (SbString &fielddata)

virtual int	getFields (SoFieldList &l) const

virtual int	getAllFields (SoFieldList &l) const

virtual SoField *	getField (const SbName &name) const

virtual SoField *	getEventIn (const SbName &name) const

virtual SoField *	getEventOut (const SbName &name) const

SbBool	getFieldName (const SoField *const field, SbName &name) const

SbBool	enableNotify (const SbBool flag)

SbBool	isNotifyEnabled (void) const

SbBool	set (const char fielddata, SoInput input)

void	get (SbString &fielddata, SoOutput *out)

virtual SbBool	validateNewFieldValue (SoField field, void newval)

virtual void	addWriteReference (SoOutput *out, SbBool isfromfield=FALSE)

SbBool	getIsBuiltIn (void) const

virtual void	getFieldsMemorySize (size_t &managed, size_t &unmanaged) const

void	setUserData (void *userdata) const

void *	getUserData (void) const

Public Member Functions inherited from SoBase
void	ref (void) const

void	unref (void) const

void	unrefNoDelete (void) const

int32_t	getRefCount (void) const

void	touch (void)

SbBool	isOfType (SoType type) const
	Returns `TRUE` if the type of this object is either of the same type or inherited from type. More...

virtual SbName	getName (void) const

virtual void	setName (const SbName &newname)

void	addAuditor (void *const auditor, const SoNotRec::Type type)

void	removeAuditor (void *const auditor, const SoNotRec::Type type)

const SoAuditorList &	getAuditors (void) const

SbBool	shouldWrite (void)

void	assertAlive (void) const

Static Public Member Functions
static SoType	getClassTypeId (void)

static void	initClass (void)

Static Public Member Functions inherited from SoShape
static SoType	getClassTypeId (void)

static void	initClass (void)

static void	getScreenSize (SoState *const state, const SbBox3f &boundingbox, SbVec2s &rectsize)

static float	getDecimatedComplexity (SoState *state, float complexity)

Static Public Member Functions inherited from SoNode
static uint32_t	getCompatibilityTypes (const SoType &nodetype)

static SoType	getClassTypeId (void)

static SoNode *	getByName (const SbName &name)

static int	getByName (const SbName &name, SoNodeList &l)

static void	initClass (void)

static void	initClasses (void)

static uint32_t	getNextNodeId (void)

static int	getActionMethodIndex (const SoType type)

static void	getBoundingBoxS (SoAction action, SoNode node)

static void	GLRenderS (SoAction action, SoNode node)

static void	callbackS (SoAction action, SoNode node)

static void	getMatrixS (SoAction action, SoNode node)

static void	handleEventS (SoAction action, SoNode node)

static void	pickS (SoAction action, SoNode node)

static void	rayPickS (SoAction action, SoNode node)

static void	searchS (SoAction action, SoNode node)

static void	writeS (SoAction action, SoNode node)

static void	audioRenderS (SoAction action, SoNode node)

static void	getPrimitiveCountS (SoAction action, SoNode node)

Static Public Member Functions inherited from SoFieldContainer
static void	initClass (void)

static SoType	getClassTypeId (void)

static void	cleanupClass (void)

static void	initCopyDict (void)

static void	addCopy (const SoFieldContainer orig, const SoFieldContainer copy)

static SoFieldContainer *	checkCopy (const SoFieldContainer *orig)

static SoFieldContainer *	findCopy (const SoFieldContainer *orig, const SbBool copyconnections)

static void	copyDone (void)

Static Public Member Functions inherited from SoBase
static void	initClass (void)
	Sets up initialization for data common to all instances of this class, like submitting necessary information to the Coin type system.

static SoType	getClassTypeId (void)
	This static method returns the SoType object associated with objects of this class.

static void	addName (SoBase const base, const char const name)

static void	removeName (SoBase const base, const char const name)

static void	incrementCurrentWriteCounter (void)

static void	decrementCurrentWriteCounter (void)

static SoBase *	getNamedBase (const SbName &name, SoType type)

static int	getNamedBases (const SbName &name, SoBaseList &baselist, SoType type)

static SbBool	read (SoInput input, SoBase &base, SoType expectedtype)

static void	setInstancePrefix (const SbString &c)

static void	setTraceRefs (SbBool trace)

static SbBool	getTraceRefs (void)

static SbBool	connectRoute (SoInput *input, const SbName &fromnodename, const SbName &fromfieldname, const SbName &tonodename, const SbName &tofieldname)

static SbBool	readRoute (SoInput *input)

Public Attributes
SoSFInt32	numControlPoints

SoMFFloat	knotVector

Protected Member Functions
virtual const SoFieldData *	getFieldData (void) const

virtual	~SoNurbsCurve ()

virtual void	generatePrimitives (SoAction *action)

virtual void	computeBBox (SoAction *action, SbBox3f &box, SbVec3f &center)

virtual SoDetail *	createLineSegmentDetail (SoRayPickAction action, const SoPrimitiveVertex v1, const SoPrimitiveVertex v2, SoPickedPoint pp)

Protected Member Functions inherited from SoShape
	SoShape (void)

virtual	~SoShape ()

float	getComplexityValue (SoAction *action)

virtual SbBool	shouldGLRender (SoGLRenderAction *action)

void	beginSolidShape (SoGLRenderAction *action)

void	endSolidShape (SoGLRenderAction *action)

void	GLRenderBoundingBox (SoGLRenderAction *action)

SbBool	shouldPrimitiveCount (SoGetPrimitiveCountAction *action)

SbBool	shouldRayPick (SoRayPickAction *const action)

void	computeObjectSpaceRay (SoRayPickAction *const action)

void	computeObjectSpaceRay (SoRayPickAction *const action, const SbMatrix &matrix)

virtual SoDetail *	createTriangleDetail (SoRayPickAction action, const SoPrimitiveVertex v1, const SoPrimitiveVertex v2, const SoPrimitiveVertex v3, SoPickedPoint *pp)

virtual SoDetail *	createPointDetail (SoRayPickAction action, const SoPrimitiveVertex v, SoPickedPoint *pp)

void	invokeTriangleCallbacks (SoAction const action, const SoPrimitiveVertex const v1, const SoPrimitiveVertex const v2, const SoPrimitiveVertex const v3)

void	invokeLineSegmentCallbacks (SoAction const action, const SoPrimitiveVertex const v1, const SoPrimitiveVertex *const v2)

void	invokePointCallbacks (SoAction const action, const SoPrimitiveVertex const v)

void	beginShape (SoAction const action, const TriangleShape shapetype, SoDetail const detail=NULL)

void	shapeVertex (const SoPrimitiveVertex *const v)

void	endShape (void)

void	generateVertex (SoPrimitiveVertex const pv, const SbVec3f &point, const SbBool useTexFunc, const SoMultiTextureCoordinateElement const tce, const float s, const float t, const SbVec3f &normal)

void	generateVertex (SoPrimitiveVertex const pv, const SbVec3f &point, const SbBool useTexFunc, const SoMultiTextureCoordinateElement const tce, const float s, const float t, const float r, const SbVec3f &normal)

SbBool	startVertexArray (SoGLRenderAction action, const SoCoordinateElement coords, const SbVec3f *pervertexnormals, const SbBool texpervertex, const SbBool colorpervertex)

void	finishVertexArray (SoGLRenderAction *action, const SbBool vbo, const SbBool normpervertex, const SbBool texpervertex, const SbBool colorpervertex)

Protected Member Functions inherited from SoNode
	SoNode (void)

virtual	~SoNode ()

virtual SbBool	readInstance (SoInput *in, unsigned short flags)

Protected Member Functions inherited from SoFieldContainer
	SoFieldContainer (void)

virtual	~SoFieldContainer ()

Protected Member Functions inherited from SoBase
	SoBase (void)

virtual	~SoBase ()

virtual void	destroy (void)

SbBool	hasMultipleWriteRefs (void) const

SbBool	writeHeader (SoOutput *out, SbBool isgroup, SbBool isengine) const

void	writeFooter (SoOutput *out) const

virtual const char *	getFileFormatName (void) const

virtual SoNotRec	createNotRec (void)

Static Protected Member Functions
static const SoFieldData **	getFieldDataPtr (void)

Static Protected Member Functions inherited from SoShape
static const SoFieldData **	getFieldDataPtr (void)

Static Protected Member Functions inherited from SoNode
static const SoFieldData **	getFieldDataPtr (void)

static void	setNextActionMethodIndex (int index)

static int	getNextActionMethodIndex (void)

static void	incNextActionMethodIndex (void)

static void	setCompatibilityTypes (const SoType &nodetype, const uint32_t bitmask)

Static Protected Member Functions inherited from SoBase
static uint32_t	getCurrentWriteCounter (void)

static void	staticDataLock (void)

static void	staticDataUnlock (void)

Additional Inherited Members
Public Types inherited from SoShape
enum	TriangleShape { TRIANGLE_STRIP, TRIANGLE_FAN, TRIANGLES, POLYGON, QUADS, QUAD_STRIP, POINTS, LINES, LINE_STRIP }

Public Types inherited from SoNode
enum	NodeType { INVENTOR = 0x0000, VRML1 = 0x0001, VRML2 = 0x0002, INVENTOR_1 = 0x0004, INVENTOR_2_0 = 0x0008, INVENTOR_2_1 = 0x0010, INVENTOR_2_5 = 0x0020, INVENTOR_2_6 = 0x0040, COIN_1_0 = 0x0080, COIN_2_0 = 0x0100, EXTENSION = 0x0200, COIN_2_2 = 0x0400, COIN_2_3 = 0x0800, COIN_2_4 = 0x1000, INVENTOR_5_0 = 0x2000, COIN_2_5 = 0x4000, COIN_3_0 = 0x8000, INVENTOR_6_0 = 0x10000, COIN_4_0 = 0x20000 }

Protected Types inherited from SoBase
enum	BaseFlags { IS_ENGINE = 0x01, IS_GROUP = 0x02 }

Protected Attributes inherited from SoNode
uint32_t	uniqueId

Protected Attributes inherited from SoFieldContainer
SbBool	isBuiltIn

Static Protected Attributes inherited from SoNode
static uint32_t	nextUniqueId = 1

static int	nextActionMethodIndex = 0

Detailed Description

The SoNurbsCurve class is a node for representing smooth curves.

A general explanation of NURBS is beyond the scope of the Coin documentation. For detailed information, refer to the specialized literature on the topic (for example "An Introduction to NURBS: With Historical Perspective" by David F. Rogers). A basic overview of curve and surface rendering using NURBS can be found in chapter 8 of "The Inventor Mentor".

Note that knot values should be specified as [0, 1, 2,..., a] rather than [0, 1/a, 2/a,..., 1] to avoid tesselation errors due to floating point precision problems. (Even if the rendered curve looks correct, such issues might surface when e.g. doing picking, since the tesselated representation used internally is not the same as the one you see rendered by OpenGL on-screen.)

Each control point has a weight that changes the shape of its basis function. Weight is analogous to having magnets pulling on the curve. Coordinate3 sets control points to have an equal weight of 1.0 (nonrational). Use Coordinate4 to specify x, y, z and weight values (rational).

A small usage example (drawing a circle using a rational curve):

#Inventor V2.1 ascii
Coordinate4 {
   point [
     0.0 -5.0     0.0 1.0,
     2.5 -2.5     0.0 0.5,
     2.5 -0.66987 0.0 1.0,
     0.0  1.94013 0.0 0.5,
    -2.5 -0.66987 0.0 1.0,
    -2.5 -2.5     0.0 0.5,
     0.0 -5.0     0.0 1.0
   ]
}
NurbsCurve {
   numControlPoints 7
   knotVector [ 0, 0, 0, 1, 1, 2, 2, 3, 3, 3 ]
}
# debug: show all the control points
BaseColor { rgb 1 1 0 }
DrawStyle { pointSize 3 }
PointSet { numPoints 7 }

FILE FORMAT/DEFAULTS:

NurbsCurve {
    numControlPoints 0
    knotVector 0
}

Constructor & Destructor Documentation

SoNurbsCurve::SoNurbsCurve ( void )

Constructor.

SoNurbsCurve::~SoNurbsCurve ( )

protectedvirtual

Destructor.

Member Function Documentation

SoType SoNurbsCurve::getTypeId ( void ) const

virtual

Returns the type identification of an object derived from a class inheriting SoBase. This is used for run-time type checking and "downward" casting.

Usage example:

void foo(SoNode * node)
{
  if (node->getTypeId() == SoFile::getClassTypeId()) {
    SoFile * filenode = (SoFile *)node;  // safe downward cast, knows the type
  }
}

For application programmers wanting to extend the library with new nodes, engines, nodekits, draggers or others: this method needs to be overridden in all 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 Inventor/nodes/SoSubNode.h (SO_NODE_INIT_CLASS and SO_NODE_CONSTRUCTOR for node classes), Inventor/engines/SoSubEngine.h (for engine classes) and so on.

For more information on writing Coin extensions, see the class documentation of the toplevel superclasses for the various class groups.

Reimplemented from SoShape.

const SoFieldData * SoNurbsCurve::getFieldData ( void ) const

protectedvirtual

Returns a pointer to the class-wide field data storage object for this instance. If no fields are present, returns NULL.

Reimplemented from SoShape.

void SoNurbsCurve::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 SoShape.

void SoNurbsCurve::rayPick ( SoRayPickAction * action )

virtual

Calculates picked point based on primitives generated by subclasses.

Reimplemented from SoShape.

void SoNurbsCurve::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.

void SoNurbsCurve::getBoundingBox ( SoGetBoundingBoxAction * action )

virtual

Redefined to notify open caches that this shape contains lines.

Reimplemented from SoShape.

void SoNurbsCurve::sendPrimitive	(	SoAction *	,
		SoPrimitiveVertex *
	)

This method is part of the original SGI Inventor API, but not implemented in Coin, as it looks like a method that should probably have been private in Open Inventor.

void SoNurbsCurve::generatePrimitives ( SoAction * action )

protectedvirtual

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.

void SoNurbsCurve::computeBBox	(	SoAction *	action,
		SbBox3f &	box,
		SbVec3f &	center
	)

protectedvirtual

Calculates the bounding box of all control points, and sets the center to the average of these points.

Implements SoShape.

SoDetail * SoNurbsCurve::createLineSegmentDetail	(	SoRayPickAction *	action,
		const SoPrimitiveVertex *	v1,
		const SoPrimitiveVertex *	v2,
		SoPickedPoint *	pp
	)

protectedvirtual

Will create line detail for a SoPickedPoint. This method will only be called internally, when generatePrimitives() is used for picking (SoShape::rayPick() is not overridden).

This method returns NULL in Open Inventor, and subclasses will need to override this method to create details for a SoPickedPoint.

This is not necessary with Coin. Of course, if you choose to override it, it will work in the same way as Open Inventor.

For this to work, you must supply a face or line detail when generating primitives. If you supply NULL for the detail argument in SoShape::beginShape(), you'll have to override this method.

Reimplemented from SoShape.

Member Data Documentation

SoSFInt32 SoNurbsCurve::numControlPoints

Number of control points to use in this NURBS curve.

SoMFFloat SoNurbsCurve::knotVector

The knot vector.

Values should be specified as [0, 1, 2,..., a] rather than [0, 1/a, 2/a,..., 1] to avoid tesselation errors due to floating point precision problems.

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

SoNurbsCurve.h
SoNurbsCurve.cpp

Public Member Functions

Static Public Member Functions

Public Attributes

Protected Member Functions

Static Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation