SoNurbsCurve(3)

📦 version 2.5.0, in fedora 43, fedora 44

💖 NAME 💖

SoNurbsCurve — bestie, this class is a node for representing smooth curves. That's the whole assignment. ✨

This page is SoNurbsCurve(3) from the Library Functions Manual, and it is long, so we're splitting it up — this is part 1. 🫶

🌸 SYNOPSIS 🌸

#include <Inventor/nodes/SoNurbsCurve.h>

Inherits SoShape.

👑 Public Member Functions

  • virtual SoType getTypeId (void) const
  • 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=0) 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=0)
  • 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 *in)
  • void get (SbString &fielddata, SoOutput *out)
  • virtual SbBool validateNewFieldValue (SoField *field, void *newval)
  • virtual void addWriteReference (SoOutput *out, SbBool isfromfield=0)
  • SbBool getIsBuiltIn (void) 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
  • 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 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)
  • static SoType getClassTypeId (void)
  • 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 *in, SoBase *&base, SoType expectedtype)
  • static void setInstancePrefix (const SbString &c)
  • static void setTraceRefs (SbBool trace)
  • static SbBool getTraceRefs (void)
  • static SbBool connectRoute (SoInput *in, const SbName &fromnodename, const SbName &fromfieldname, const SbName &tonodename, const SbName &tofieldname)
  • static SbBool readRoute (SoInput *in)

🎀 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 SoTextureCoordinateElement *const tce, const float s, const float t, const SbVec3f &normal)
  • void generateVertex (SoPrimitiveVertex *const pv, const SbVec3f &point, const SbBool useTexFunc, const SoTextureCoordinateElement *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)
  • ~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

🌈 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)

🫶 Friends

  • class SoNurbsCurveP

okay that's the synopsis bestie, it's giving encyclopedia but make it cute 💅 and there is so much more coming — keep scrolling, part 2 is right there 👑

Additional Inherited Members 💫

okay so before we get into the main character lore, here's all the stuff SoNurbsCurve just casually inherits because it's built different. no cap, this is the family tree:

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
    }

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 = 0
  • static int nextActionMethodIndex = 0

Detailed Description 📖

SoNurbsCurve is the node that represents smooth curves. that's it, that's the vibe. it's giving ✨curvy✨.

okay so real talk: a whole general explanation of NURBS is way beyond what the Coin docs are gonna cover, bestie, that's not the assignment. if you want the full lore, go read the actual literature on it — for example "An Introduction to NURBS: WithHistorical Perspective" by David F. Rogers. and if you want a basic overview of curve and surface rendering with NURBS, chapter 8 of "The Inventor Mentor" has you covered. 📚

⚠️ listen up because this one MATTERS: knot values should be specified as [0, 1, 2,..., a] and not as [0, 1/a, 2/a,..., 1]. why? to avoid tesselation errors due to floating point precision problems. and yes, even if the rendered curve looks correct, those issues might surface when e.g. doing picking — because the tesselated representation used internally is not the same as the one you see rendered by OpenGL on-screen. 😭 so just do it the right way, fr fr.

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. the birth of a legend 💅

References knotVector, numControlPoints, and SoNurbsCurve().

Referenced by getFieldData(), and SoNurbsCurve().

SoNurbsCurve::~SoNurbsCurve () [protected], [virtual]

Destructor. she's leaving the group chat 😭

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
  }
  else if (node->getTypeId().isOfType(SoGroup::getClassTypeId())) {
    SoGroup * group = (SoGroup *)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. so many macros, so little time 🫠

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 [protected], [virtual]

Returns a pointer to the class-wide field data storage object for this instance. If no fields are present, returns NULL. (iconic behaviour: sometimes there's just... nothing there 💀)

Reimplemented from SoShape.

References SoNurbsCurve().

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. yes, literally throwing primitives at OpenGL, that's the whole job 🌸

Reimplemented from SoShape.

References SoAction::getState(), SoState::pop(), SoState::push(), and SoShape::shouldGLRender().

void SoNurbsCurve::rayPick (SoRayPickAction * action) [virtual]

Calculates picked point based on primitives generated by subclasses.

Reimplemented from SoShape.

References SoAction::getState(), SoState::pop(), SoDebugError::postWarning(), SoState::push(), SoShape::rayPick(), and SoShape::shouldRayPick().

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. counting era 🔢

Nodes influencing how geometry nodes calculates their primitive count also overrides this method to change the relevant state variables.

Reimplemented from SoShape.

References SoShape::getPrimitiveCount().

void SoNurbsCurve::getBoundingBox (SoGetBoundingBoxAction * action) [virtual]

Redefined to notify open caches that this shape contains lines. like, hey caches, heads up, there are lines in here 📢

Reimplemented from SoShape.

References SoShape::getBoundingBox(), and SoAction::getState().

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

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. so yeah, it's just kinda standing there, existing, doing nothing 🙈

void SoNurbsCurve::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().) ok so don't do that, noted 📝

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) [protected], [virtual]

Calculates the bounding box of all control points, and sets the center to the average of these points. math girlies stay winning 📐✨

Implements SoShape.

References SbBox3f::extendBy(), SoAction::getState(), SbBox3f::makeEmpty(), and numControlPoints.

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

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. so you can, you just don't have to 💅

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. no skipping steps bestie 🙅

Reimplemented from SoShape.

Member Data Documentation 📦

SoSFInt32 SoNurbsCurve::numControlPoints

Number of control points to use in this NURBS curve. simple as that 🎀

Referenced by computeBBox(), and SoNurbsCurve().

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. (yes, again. it's that serious. floating point will betray you 😤)

Referenced by SoNurbsCurve().

Author ✍️

Generated automatically by Doxygen for Coin from the source code. not a human, just a robot doing its little thing 🤖💖

okay bestie that's the whole page, you made it to the end and you ate fr fr 👑 and if you're wondering where this all came from: it's Coin, Version 2.5.0, dated SoNurbsCurve(3) — so go forth and draw some smooth curves, you absolute icon 🦋✨

📦 where this page comes from