SoShapeHints Class Reference

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SoShapeHints Class Reference
Node Classes

The SoShapeHints class is a node containing hints about how to render geometry.The SoShapeHints node is used to set up clues to the rendering subsystem about how particular aspects of the subsequent geometry in the scene graph should be drawn. More...

`#include <Inventor/nodes/SoShapeHints.h>`

Inheritance diagram for SoShapeHints:

## Public Types
enum | VertexOrdering { UNKNOWN_ORDERING = SoShapeHintsElement::UNKNOWN_ORDERING, CLOCKWISE = SoShapeHintsElement::CLOCKWISE, COUNTERCLOCKWISE = SoShapeHintsElement::COUNTERCLOCKWISE }
enum | ShapeType { UNKNOWN_SHAPE_TYPE = SoShapeHintsElement::UNKNOWN_SHAPE_TYPE, SOLID = SoShapeHintsElement::SOLID }
enum | FaceType { UNKNOWN_FACE_TYPE = SoShapeHintsElement::UNKNOWN_FACE_TYPE, CONVEX = SoShapeHintsElement::CONVEX }
enum | WindingType { NO_WINDING_TYPE = 0 }
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 }

## Public Member Functions
virtual SoType | getTypeId (void) const
| SoShapeHints (void)
virtual void | doAction (SoAction *action)
virtual void | GLRender (SoGLRenderAction *action)
virtual void | callback (SoCallbackAction *action)
virtual void | getBoundingBox (SoGetBoundingBoxAction *action)
virtual void | pick (SoPickAction *action)
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 SbBool | affectsState (void) const
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 | rayPick (SoRayPickAction *action)
virtual void | search (SoSearchAction *action)
virtual void | write (SoWriteAction *action)
virtual void | audioRender (SoAudioRenderAction *action)
virtual void | getPrimitiveCount (SoGetPrimitiveCountAction *action)
virtual void | grabEventsSetup (void)
virtual void | grabEventsCleanup (void)
virtual void | startNotify (void)
virtual void | notify (SoNotList *l)
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
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 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)
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 *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
SoSFEnum | vertexOrdering
SoSFEnum | shapeType
SoSFEnum | faceType
SoSFEnum | windingType
SoSFBool | useVBO
SoSFFloat | creaseAngle

## Protected Member Functions
virtual const SoFieldData * | getFieldData (void) const
virtual | ~SoShapeHints ()
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

## Static Protected Member Functions
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
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 SoShapeHints class is a node containing hints about how to render geometry.

The SoShapeHints node is used to set up clues to the rendering subsystem about how particular aspects of the subsequent geometry in the scene graph should be drawn.

The default settings of the rendering system is tuned towards programmer convenience. For instance, the default is to render both sides of all polygons to make sure we avoid any "holes" in the geometry if the vertex ordering should happen to differ for different polygons.

If the programmer gives up some of this convenience and uses SoShapeHints nodes to more closely specify information about the scene graph geometry, the clues given by the SoShapeHints node(s) will then be used by the rendering subsystem to avoid certain costly operations. Significant gains in rendering speed could be seen as a result.

Be aware that the way backface culling and two-sided lighting is decided by the rendering system is not at all intuitive. Here are the common rules of how primitive shapes will render themselves with regard to how the SoShapeHints::vertexOrdering and SoShapeHints::shapeType fields are set:

- vertexOrdering == CLOCKWISE or COUNTERCLOCKWISE, shapeType == SOLID: causes primitives to be backface culled and rendered with one-sided lighting.

- vertexOrdering == CLOCKWISE or COUNTERCLOCKWISE, shapeType == UNKNOWN_SHAPE_TYPE: primitives are not backface culled, and they are rendered with two-sided lighting.

- vertexOrdering == UNKNOWN_ORDERING, any shapeType: primitives are not backface culled, and they are rendered with one-sided lighting. The OpenGL vertex ordering will be set to counter clockwise ordering.

The UNKNOWN_ORDERING enum has a special and non-intuitive meaning. The ordering is really set to counter clockwise – in OpenGL and when generating normals. However, if you want to render your geometry with one-sided lighting and backface culling disabled, you have to use this enum value, and your polygons need to be in counter clockwise ordering.

FILE FORMAT/DEFAULTS:

ShapeHints {
vertexOrdering UNKNOWN_ORDERING
shapeType UNKNOWN_SHAPE_TYPE
faceType CONVEX
creaseAngle 0
}

## Member Enumeration Documentation

enum SoShapeHints::VertexOrdering

Enumeration of available ways to specify ordering of vertices for a polygon.

Enumerator
UNKNOWN_ORDERING | Ordering not known, render both sides of the polygon.
CLOCKWISE | Vertices are specified in a clockwise order.
COUNTERCLOCKWISE | Vertices are specified in a counter-clockwise order.

enum SoShapeHints::ShapeType

Enumeration of different shape types.

Enumerator
UNKNOWN_SHAPE_TYPE | Nothing known about the shape, be conservative when rendering.
SOLID | The subsequent shapes in the graph are all known to be completely "closed", solid 3D shapes. Backface culling will be done if vertexOrdering is known.

enum SoShapeHints::FaceType

Enumeration of polygon face types.

Enumerator
UNKNOWN_FACE_TYPE | Signifies: nothing is known about subsequent polygon data, be conservative when rendering. All polygons in the scene will be analyzed to see if they needs to be tessellated (broken up) into triangles before passed on to the underlying immediate mode rendering system. The OpenGL rendering system handles most complex polygon types, but not all: it can for instance have problems with many-sided, concave polygons (concave polygons are "hollow", that is: rounded inwards). Coin's internal tessellator will most often handle the cases that OpenGL fails on. So if you are seeing weird artifacts in how complex polygons are rendered, try to change the SoShapeHints::faceType field to this value and see if they are then rendered correctly. Beware that turning on this functionality might have the effect of making the rendering performance worse. If it has a noticable effect on your particular scenegraph, we advise that you investigate whether you could change how the polygons are generated for Coin rendering and then avoid using this flag.
CONVEX | Subsequent faces are all convex, so turn off the check for and tessellation of inconvex faces. Subsequent polygons from faceset-type nodes (like SoFaceSet and SoIndexedFaceSet) will be sent unmodified to OpenGL, thereby assuming that the polygons are in a form handled by OpenGL.

## Constructor & Destructor Documentation

SoShapeHints::SoShapeHints | ( | void |  | ) |

Constructor.

SoShapeHints::~SoShapeHints | ( |  | ) |
| protectedvirtual

Destructor.

## Member Function Documentation

SoType SoShapeHints::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.

Implements SoBase.

const SoFieldData * SoShapeHints::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 SoFieldContainer.

void SoShapeHints::doAction | ( | SoAction * | action | ) |
| virtual

This function performs the typical operation of a node for any action.

Reimplemented from SoNode.

void SoShapeHints::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 SoNode.

void SoShapeHints::callback | ( | SoCallbackAction * | action | ) |
| virtual

Action method for SoCallbackAction.

Simply updates the state according to how the node behaves for the render action, so the application programmer can use the SoCallbackAction for extracting information about the scene graph.

Reimplemented from SoNode.

void SoShapeHints::getBoundingBox | ( | SoGetBoundingBoxAction * | action | ) |
| virtual

Action method for the SoGetBoundingBoxAction.

Calculates bounding box and center coordinates for node and modifies the values of the action to encompass the bounding box for this node and to shift the center point for the scene more towards the one for this node.

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

Reimplemented from SoNode.

void SoShapeHints::pick | ( | SoPickAction * | action | ) |
| virtual

Action method for SoPickAction.

Does common processing for SoPickAction action instances.

Reimplemented from SoNode.

## Member Data Documentation

SoSFEnum SoShapeHints::vertexOrdering

Specifies how vertices are ordered for polygon faces.

Set this field to SoShapeHints::CLOCKWISE or SoShapeHints::COUNTERCLOCKWISE if possible to turn on backface culling and thereby optimize rendering.

Default value is SoShapeHints::UNKNOWN_ORDERING.

SoSFEnum SoShapeHints::shapeType

Hint about whether or not shapes are known to be "closed". Default value is SoShapeHints::UNKNOWN_SHAPE_TYPE.

SoSFEnum SoShapeHints::faceType

Hint about whether or not polygon faces are known to be convex. Default value is SoShapeHints::CONVEX.

SoSFFloat SoShapeHints::creaseAngle

When normals are automatically generated by Coin (i.e. SoNormal nodes are not used), this is the smallest angle between two faces where we would still calculate normals to do flatshading.

If the angle between the normals of two neighboring faces is less than the value of this field, the faces will be smoothshaded around their common edge.

The angle is specified in radians, and the default value is 0.0, meaning no smoothing will be done by default.

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

- SoShapeHints.h
- SoShapeHints.cpp

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