SYNOPSIS
#include <Inventor/VRMLnodes/SoVRMLExtrusion.h>
Inherits SoVRMLGeometry.
Public Member Functions
virtual SoType getTypeId (void) const
SoVRMLExtrusion (void)
virtual void GLRender (SoGLRenderAction *action)
virtual void getPrimitiveCount (SoGetPrimitiveCountAction *action)
virtual void computeBBox (SoAction *action, SbBox3f &bbox, SbVec3f ¢er)
Static Public Member Functions
static SoType getClassTypeId (void)
static void initClass (void)
Public Attributes
SoSFBool beginCap
SoSFBool ccw
SoSFBool convex
SoSFFloat creaseAngle
SoMFVec2f crossSection
SoSFBool endCap
SoMFRotation orientation
SoMFVec2f scale
SoSFBool solid
SoMFVec3f spine
Protected Member Functions
virtual const SoFieldData * getFieldData (void) const
virtual ~SoVRMLExtrusion ()
virtual void notify (SoNotList *list)
virtual void generatePrimitives (SoAction *action)
virtual SoDetail * createTriangleDetail (SoRayPickAction *action, const SoPrimitiveVertex *v1, const SoPrimitiveVertex *v2, const SoPrimitiveVertex *v3, SoPickedPoint *pp)
Static Protected Member Functions
static const SoFieldData ** getFieldDataPtr (void)
Detailed Description
The SoVRMLExtrusion class is a a geometry node for extruding a cross section along a spine.
The detailed class documentation is taken verbatim from the VRML97 standard (ISO/IEC 14772-1:1997). It is copyright The Web3D Consortium, and is used by permission of the Consortium:
Extrusion { eventIn MFVec2f set_crossSection eventIn MFRotation set_orientation eventIn MFVec2f set_scale eventIn MFVec3f set_spine field SFBool beginCap TRUE field SFBool ccw TRUE field SFBool convex TRUE field SFFloat creaseAngle 0 # [0,inf) field MFVec2f crossSection [ 1 1, 1 -1, -1 -1, -1 1, 1 1 ] # (-inf,inf) field SFBool endCap TRUE field MFRotation orientation 0 0 1 0 # [-1,1],(-inf,inf) field MFVec2f scale 1 1 # (0,inf) field SFBool solid TRUE field MFVec3f spine [ 0 0 0, 0 1 0 ] # (-inf,inf) }.fi Introduction The Extrusion node specifies geometric shapes based on a two dimensional cross-section extruded along a three dimensional spine in the local coordinate system. The cross-section can be scaled and rotated at each spine point to produce a wide variety of shapes. An Extrusion node is defined by:
- a 2D crossSection piecewise linear curve (described as a series of connected vertices);
- a 3D spine piecewise linear curve (also described as a series of connected vertices);
- a list of 2D scale parameters;
- a list of 3D orientation parameters.
- •
- For all points other than the first or last: The Y-axis for spine[i] is found by normalizing the vector defined by (spine[i+1]
- •
- spine[i-1]).
- If the spine curve is closed: The SCP for the first and last points is the same and is found using (spine[1] - spine[n-2]) to compute the Y-axis.
- If the spine curve is not closed: The Y-axis used for the first point is the vector from spine[0] to spine[1], and for the last it is the vector from spine[n-2] to spine[n-1].
- For all points other than the first or last: Take the following cross-product:
- If the spine curve is closed: The SCP for the first and last points is the same and is found by taking the following cross- product:
- If the spine curve is not closed: The Z-axis used for the first spine point is the same as the Z-axis for spine[1]. The Z- axis used for the last spine point is the same as the Z-axis for spine[n-2].
- After determining the Z-axis, its dot product with the Z-axis of the previous spine point is computed. If this value is negative, the Z-axis is flipped (multiplied by -1). In most cases, this prevents small changes in the spine segment angles from flipping the cross-section 180 degrees.
- Surfaces of revolution: If the cross-section is an approximation of a circle and the spine is straight, the Extrusion is equivalent to a surface of revolution, where the scale parameters define the size of the cross-section along the spine.
- Uniform extrusions: If the scale is (1, 1) and the spine is straight, the cross-section is extruded uniformly without twisting or scaling along the spine. The result is a cylindrical shape with a uniform cross section.
- Bend/twist/taper objects: These shapes are the result of using all fields. The spine curve bends the extruded shape defined by the cross-section, the orientation parameters (given as rotations about the Y-axis) twist it around the spine, and the scale parameters taper it (by scaling about the spine).
Constructor & Destructor Documentation
SoVRMLExtrusion::SoVRMLExtrusion (void)
Constructor.SoVRMLExtrusion::~SoVRMLExtrusion () [protected], [virtual]
Destructor.Member Function Documentation
SoType SoVRMLExtrusion::getClassTypeId (void) [static]
This static method returns the SoType object associated with objects of this class.Reimplemented from SoVRMLGeometry.
SoType SoVRMLExtrusion::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 SoVRMLGeometry.
const SoFieldData ** SoVRMLExtrusion::getFieldDataPtr (void) [static], [protected]
This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.Reimplemented from SoVRMLGeometry.
const SoFieldData * SoVRMLExtrusion::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.Reimplemented from SoVRMLGeometry.
void SoVRMLExtrusion::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 SoVRMLGeometry.
void SoVRMLExtrusion::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 SoVRMLExtrusion::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 SoVRMLExtrusion::computeBBox (SoAction *action, SbBox3f &box, SbVec3f ¢er) [virtual]
Implemented by SoShape subclasses to let the SoShape superclass know the exact size and weighted center point of the shape's bounding box.The bounding box and center point should be calculated and returned in the local coordinate system.
The method implements action behavior for shape nodes for SoGetBoundingBoxAction. It is invoked from SoShape::getBoundingBox(). (Subclasses should not override SoNode::getBoundingBox().)
The box parameter sent in is guaranteed to be an empty box, while center is undefined upon function entry.
Implements SoShape.
void SoVRMLExtrusion::notify (SoNotList *l) [protected], [virtual]
Notifies all auditors for this instance when changes are made.Reimplemented from SoVRMLGeometry.
void SoVRMLExtrusion::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.
SoDetail * SoVRMLExtrusion::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.
Author
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