Provided by: libcoin60-doc_3.1.3-2_all bug

NAME

       SoNurbsSurface -

       The SoNurbsSurface class is used to render smooth surfaces.

       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'.

SYNOPSIS

       #include <Inventor/nodes/SoNurbsSurface.h>

       Inherits SoShape.

   Public Member Functions
       SoNurbsSurface (void)
       virtual void GLRender (SoGLRenderAction *action)
       virtual void rayPick (SoRayPickAction *action)
       virtual void getPrimitiveCount (SoGetPrimitiveCountAction *action)
       void sendPrimitive (SoAction *, SoPrimitiveVertex *)

   Static Public Member Functions
       static void initClass (void)

   Public Attributes
       SoSFInt32 numUControlPoints
       SoSFInt32 numVControlPoints
       SoSFInt32 numSControlPoints
       SoSFInt32 numTControlPoints
       SoMFFloat uKnotVector
       SoMFFloat vKnotVector
       SoMFFloat sKnotVector
       SoMFFloat tKnotVector

   Protected Member Functions
       virtual ~SoNurbsSurface ()
       virtual void generatePrimitives (SoAction *action)
       virtual void computeBBox (SoAction *action, SbBox3f &box, SbVec3f &center)
       SoDetail * createTriangleDetail (SoRayPickAction *action, const SoPrimitiveVertex *v1,
           const SoPrimitiveVertex *v2, const SoPrimitiveVertex *v3, SoPickedPoint *pp)

Detailed Description

       The SoNurbsSurface class is used to render smooth surfaces.

       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 surface 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.)

       A basic usage example:

         #Inventor V2.1 ascii

         ShapeHints {
           vertexOrdering COUNTERCLOCKWISE
         }

         Coordinate3 {
            point [
              -3 -3 -3, -3 -1 -3, -3  1 -3, -3  3 -3,
              -1 -3 -3, -1 -1  3, -1  1  3, -1  3 -3,
               1 -3 -3,  1 -1  3,  1  1  3,  1  3 -3,
               3 -3 -3,  3 -1 -3,  3  1 -3,  3  3 -3
             ]
         }

         NurbsSurface {
            numUControlPoints 4
            numVControlPoints 4
            uKnotVector [ 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0 ]
            vKnotVector [ 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0 ]
         }

       FILE FORMAT/DEFAULTS:

           NurbsSurface {
               numUControlPoints 0
               numVControlPoints 0
               numSControlPoints 0
               numTControlPoints 0
               uKnotVector 0
               vKnotVector 0
               sKnotVector 0
               tKnotVector 0
           }

Constructor & Destructor Documentation

   SoNurbsSurface::SoNurbsSurface (void) Constructor.
   SoNurbsSurface::~SoNurbsSurface () [protected, virtual] Destructor.

Member Function Documentation

   void SoNurbsSurface::initClass (void) [static] Sets up initialization for data common to all
       instances of this class, like submitting necessary information to the Coin type system.
       Reimplemented from SoShape.

   void SoNurbsSurface::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 SoNurbsSurface::rayPick (SoRayPickAction *action) [virtual] Calculates picked point based
       on primitives generated by subclasses.
       Reimplemented from SoShape.

   void SoNurbsSurface::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 SoNurbsSurface::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 SoNurbsSurface::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().)
       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 SoNurbsSurface::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.
       Implements SoShape.

   SoDetail * SoNurbsSurface::createTriangleDetail (SoRayPickAction *action, const
       SoPrimitiveVertex *v1, const SoPrimitiveVertex *v2, const SoPrimitiveVertex *v3,
       SoPickedPoint *pp) [protected, virtual] Will create triangle 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 SoNurbsSurface::numUControlPoints Number of control points in the U direction.
   SoSFInt32 SoNurbsSurface::numVControlPoints Number of control points in the V direction.
   SoSFInt32 SoNurbsSurface::numSControlPoints Number of control points in the S direction.
   SoSFInt32 SoNurbsSurface::numTControlPoints Number of control points in the T direction.
   SoMFFloat SoNurbsSurface::uKnotVector The Bezier knot vector for the U direction.
   SoMFFloat SoNurbsSurface::vKnotVector The Bezier knot vector for the V direction.
   SoMFFloat SoNurbsSurface::sKnotVector The Bezier knot vector for the S direction.
   SoMFFloat SoNurbsSurface::tKnotVector The Bezier knot vector for the T direction.

Author

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