Open Inventor Release 2024.1.2
 
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SoVolumeBufferedShape Class Reference

VolumeViz Buffered shape node for volume data. More...

#include <VolumeViz/nodes/SoVolumeBufferedShape.h>

+ Inheritance diagram for SoVolumeBufferedShape:

Public Member Functions

virtual SoType getTypeId () const
 Returns the type identifier for this specific instance.
 
 SoVolumeBufferedShape ()
 Constructor.
 
- Public Member Functions inherited from SoBufferedShape
 SoBufferedShape ()
 Default constructor.
 
- Public Member Functions inherited from SoShape
virtual SbBool affectsState () const
 Overrides default method on SoNode.
 
ShapeType getShapeType ()
 Gets the current shape Full Scene Antialiasing type.
 
- Public Member Functions inherited from SoNode
virtual void setOverride (const SbBool state)
 Turns the override flag on or off.
 
virtual SbBool isOverride () const
 Returns the state of the override flag.
 
virtual SoNodecopy (SbBool copyConnections=FALSE) const
 Creates and returns an exact copy of the node.
 
virtual void touch ()
 Marks an instance as modified, simulating a change to it.
 
- Public Member Functions inherited from SoFieldContainer
void setToDefaults ()
 Sets all fields in this object to their default values.
 
SbBool hasDefaultValues () const
 Returns TRUE if all of the object's fields have their default values.
 
SbBool fieldsAreEqual (const SoFieldContainer *fc) const
 Returns TRUE if this object's fields are exactly equal to fc's fields.
 
void copyFieldValues (const SoFieldContainer *fc, SbBool copyConnections=FALSE)
 Copies the contents of fc's fields into this object's fields.
 
SoNONUNICODE SbBool set (const char *fieldDataString)
 Sets one or more fields in this object to the values specified in the given string, which should be a string in the Open Inventor file format.
 
SbBool set (const SbString &fieldDataString)
 Sets one or more fields in this object to the values specified in the given string, which should be a string in the Open Inventor file format.
 
void get (SbString &fieldDataString)
 Returns the values of the fields of this object in the Open Inventor ASCII file format in the given string.
 
virtual int getFields (SoFieldList &list) const
 Appends references to all of this object's fields to resultList, and returns the number of fields appended.
 
virtual int getAllFields (SoFieldList &list) const
 Returns a list of fields, including the eventIn's and eventOut's.
 
virtual SoFieldgetField (const SbName &fieldName) const
 Returns a the field of this object whose name is fieldName.
 
virtual SoFieldgetEventIn (const SbName &fieldName) const
 Returns a the eventIn with the given name.
 
virtual SoFieldgetEventOut (const SbName &fieldName) const
 Returns the eventOut with the given name.
 
SbBool getFieldName (const SoField *field, SbName &fieldName) const
 Returns the name of the given field in the fieldName argument.
 
SbBool enableNotify (SbBool flag)
 Notification at this Field Container is enabled (if flag == TRUE) or disabled (if flag == FALSE).
 
SbBool isNotifyEnabled () const
 Notification is the process of telling interested objects that this object has changed.
 
virtual void setUserData (void *data)
 Sets application data.
 
void * getUserData (void) const
 Gets user application data.
 
- Public Member Functions inherited from SoBase
virtual SbName getName () const
 Returns the name of an instance.
 
virtual void setName (const SbName &name)
 Sets the name of an instance.
 
void setSynchronizable (const bool b)
 Sets this to be a ScaleViz synchronizable object.
 
bool isSynchronizable () const
 Gets the ScaleViz synchronizable state of this object.
 
- Public Member Functions inherited from SoRefCounter
void ref () const
 Adds a reference to an instance.
 
void unref () const
 Removes a reference from an instance.
 
void unrefNoDelete () const
 unrefNoDelete() should be called when it is desired to decrement the reference count, but not delete the instance if this brings the reference count to zero.
 
int getRefCount () const
 Returns current reference count.
 
void lock () const
 lock this instance.
 
void unlock () const
 unlock this instance.
 
- Public Member Functions inherited from SoTypedObject
SbBool isOfType (const SoType &type) const
 Returns TRUE if this object is of the type specified in type or is derived from that type.
 
template<typename TypedObjectClass >
SbBool isOfType () const
 Returns TRUE if this object is of the type of class TypedObjectClass or is derived from that class.
 
- Public Member Functions inherited from SoVolumeGeometry
 SoVolumeGeometry ()
 Constructor.
 
virtual ~SoVolumeGeometry ()
 Destructor.
 
virtual void setRenderProgress (SoProgressIndicator *ps)
 Set an application defined SoProgressIndicator object which will raise an event before and after the rendering task, before and after each subtask (in this case: Texture creation and Geometry creation) and after each step in the subtasks which represents in most cases individual tiles of data.
 

Static Public Member Functions

static SoType getClassTypeId ()
 Returns the type identifier for this class.
 
- Static Public Member Functions inherited from SoBufferedShape
static SoType getClassTypeId ()
 Returns the type identifier for this class.
 
- Static Public Member Functions inherited from SoShape
static SoType getClassTypeId ()
 Returns the type identifier for this class.
 
static SbBool isPrimitiveRestartAvailable (SoState *state=NULL)
 Returns TRUE if the primitive restart feature is available.
 
- Static Public Member Functions inherited from SoNode
static SoType getClassTypeId ()
 Returns the type identifier for this class.
 
static SoNodegetByName (const SbName &name)
 A node's name can be set using SoBase::setName().
 
static int getByName (const SbName &name, SoNodeList &list)
 A node's name can be set using SoBase::setName().
 
- Static Public Member Functions inherited from SoFieldContainer
static SoType getClassTypeId ()
 Returns the type of this class.
 
- Static Public Member Functions inherited from SoBase
static SoType getClassTypeId ()
 Returns type identifier for this class.
 
- Static Public Member Functions inherited from SoTypedObject
static SoType getClassTypeId ()
 Returns the type identifier for this class.
 

Public Attributes

SoSFBool clipGeometry
 Specifies to clip the geometry at the volume boundaries.
 
SoSFFloat offset
 Sets an offset value used for computing the texture coordinates.
 
SoSFEnum interpolation
 Interpolation mode.
 
- Public Attributes inherited from SoBufferedShape
SoSFEnum shapeUsage
 Defines the usage of the shape.
 
SoSFBool primitiveRestartEnabled
 Enable/disable the primitive restart feature.
 
SoSFInt32 primitiveRestartValue
 Index value for the primitive restart feature.
 
SoSFBool useNormalsGenerator
 Indicates if the node should use the internal normal vector generator if no normals are defined.
 
SoSFEnum shapeType
 Shape type to render.
 
SoMFInt32 numVertices
 Total number of vertices/indices or number of vertices/indices to be used per primitive.
 
SoSFBufferObject vertexBuffer
 Buffer object that contains the vertex data.
 
SoSFShort vertexComponentsCount
 Number of components in each vertex.
 
SoSFEnum vertexComponentsType
 SbDataType::DataType for vertices.
 
SoSFShort vertexStride
 Stride in bytes between the first component of two consecutive vertices.
 
SoSFInt32 vertexOffset
 Offset in bytes to the first vertex within the buffer.
 
SoSFBufferObject normalBuffer
 Buffer object that contains the (optional) normal vectors.
 
SoSFEnum normalComponentsType
 SbDataType::DataType type for the normal vectors.
 
SoSFShort normalStride
 Stride in bytes between the first component of two consecutive normals.
 
SoSFInt32 normalOffset
 Offset in bytes to the first normal vector in the buffer.
 
SoSFBufferObject indexBuffer
 Buffer object that contains the (optional) indices.
 
SoSFEnum indexType
 SbDataType::DataType type for the indices.
 
SoSFInt32 indexOffset
 Offset in bytes to the first index in the buffer.
 
SoSFBufferObject colorBuffer
 Buffer object that contains the (optional) color values.
 
SoSFEnum colorComponentsType
 SbDataType::DataType type for the color values.
 
SoSFInt32 colorStride
 Stride in bytes between the first component of two consecutive colors.
 
SoSFInt32 colorOffset
 Offset in bytes to the first color value in the buffer.
 
SoSFInt32 colorComponentsCount
 Number of components in each color value.
 
SoMFBufferObject texCoordsBuffer
 Buffer objects that contains the (optional) texture coordinates.
 
SoMFEnum texCoordsComponentsType
 SbDataType::DataType type for the texture coordinates.
 
SoMFInt32 texCoordsStride
 Stride in bytes between the first component of two consecutive texture coordinates.
 
SoMFInt32 texCoordsOffset
 Offset in bytes to the first texture coordinate in the buffer.
 
SoMFInt32 texCoordsComponentsCount
 Number of components in each texture coordinate.
 
- Public Attributes inherited from SoShape
SoSFBool boundingBoxIgnoring
 Whether to ignore this node during bounding box traversal.
 

Additional Inherited Members

- Public Types inherited from SoBufferedShape
enum  Type {
  POINTS ,
  LINE_STRIP ,
  LINE_LOOP ,
  LINES ,
  TRIANGLE_STRIP ,
  TRIANGLE_FAN ,
  TRIANGLES ,
  QUAD_STRIP ,
  QUADS ,
  POLYGON
}
 Type of shape that will be rendered. More...
 
enum  Usage {
  STATIC ,
  DYNAMIC
}
 This enum is used to set the shapeUsage field. More...
 
- Public Types inherited from SoShape
enum  ShapeType {
  POINTS ,
  LINES ,
  POLYGONS ,
  TEXT
}
 Basic type for antialiased rendering for this shape (Do not consider the SoDrawStyle property currently in the state). More...
 

Detailed Description

VolumeViz Buffered shape node for volume data.

This node defines a shape which is the intersection of the volume data defined by an SoVolumeData node and the 3D shape defined by an SoBufferedShape node. The shape defined by this intersection is colored using the data values from the current SoVolumeData node and color map from the current SoTransferFunction node.

The shape defined by this intersection is textured using the data from the current SoVolumeData node and SoTransferFunction node. The interpolation field controls how the texture is interpolated. Texture coordinates are automatically computed for each vertex based on its position relative to the 3D extent of the volume. If texture coordinates are specified, they are ignored.

This node can be used to create custom "slices" through the volume, for example a cylinder slice. It can be considered a generalization of the SoOrthoSlice, SoObliqueSlice, SoFenceSlice, etc features. But note:

  • Compared to an equivalent standard slice (e.g. SoOrthoSlice), the rendering may be slightly different due to positioning and interpolation.
  • The standard slices (e.g. SoOrthoSlice) have "two-sided lighting" enabled by default as a convenience. This is not true for volume geometry nodes (which have the same default as their corresponding standard geometry node), so the "back" side of the geometry will not be lighted unless you enable two-sided lighting using an SoShapeHints node.

When set to FALSE, the clipGeometry field allows rendering of the portion of the geometry that does not intersect the volume data. This portion is not textured and is rendered as a regular SoBufferedShape.

This node uses 3D texturing and is not available if the hardware does not support this feature.

SoBufferedShape provides fields for:

  • Vertices
  • Indices (optional)
  • Colors (optional)
  • Normals (optional)
  • Texture coordinates (optional)

SoVolumeBufferedShape is useful to manage the rendering of large geometry, provide application control over where the data is stored (CPU or GPU) and to integrate rendering with the Open Inventor computing framework (through the SoBufferObject classes).

SoVolumeBufferedShape can render many types of geometric primitives including points, lines, quads and triangles. (A single type must be specified per instance of SoVolumeBufferedShape.) You specify the type of primitive in the SoSFEnum field shapeType.

SoVolumeBufferedShape can render multiple primitives of the same type. You can specify the number of vertices (or indices if provided) to use for each primitive in the SoMFInt32 field numVertices (similar to SoFaceSet).

You can also use the primitive restart feature to define multiple indexed strip shapes, for example TRIANGLE_STRIP or LINE_STRIP. The end of each primitive is marked by a special index value in the index buffer and this value can be specified in the primitiveRestartValue field. The behavior is similar to the "-1" value that can be used in Open Inventor indexed shape nodes like SoIndexedFaceSet, but is implemented on the GPU.

NOTE:

The geometry and its attributes must be stored in buffer objects (see SoBufferObject). The buffer objects can be SoGLBufferObjects stored directly on the graphics board or SoCpuBufferObjects stored in system memory. This allows the application to control what data is stored where.

If lighting is enabled (there is no SoLightModel node or the model field of the SoLightModel is set to PHONG) and the normalBuffer field is not set, then normal vectors are automatically generated, similar to other geometry nodes. Normal generation is affected by the creaseAngle field of the SoShapeHints node if the vertices are NOT indexed. If the vertices are indexed the creaseAngle is forced to PI in order to have smooth surface rendering. It is not possible to display sharp edges by using indexed vertices if the normals are not set by the application. It is possible to disable normal generation (if for example the normals are generated by a geometry shader) by setting the useNormalsGenerator field to FALSE. Note that normal generation is disabled in some cases. See the limitations section. If no normal vectors are specified or generated, and lighting is enabled, the primitive may not be rendered correctly.

SoVolumeBufferedShape provides fields to describe the content of each buffer, e.g. the data type and number of components in each buffer, as well as how to access the buffers, e.g. the offset into the buffer and "stride" separating data values in the buffer. The default values for offset and stride assume that the vertices, normals, etc are each in a separate buffer. However setting appropriate offset and stride allows, for example, vertices and normals to be interleaved in a single buffer. In this case the same buffer would be set into both the vertexBuffer and normalBuffer fields.

To disable computing the bounding box, which can take a long time with very large geometry, use the SoBBox node to specify a pre-computed bounding box.

Limitations

  • Projections:
    The projections used in the VolumeViz mechanism are not handled by SoVolumeBufferedShape.
  • Lighting:
    If there is no normalBuffer the normals are generated by Inventor. The crease angle (field of SoShapeHints) is not considered by the normal generator if the vertices are indexed (crease angle is PI). So if the application wants to render sharp edges on its shape, it must use the vertexBuffer without indices in the indexBuffer.
  • Transparency:
    If there is no color buffer, making the entire shape transparent using an SoMaterial node works as usual. However if there is a color buffer with RGBA values, note that Open Inventor does not currently check the color buffer for transparency (alpha values < 1). So in this case the SoVolumeBufferedShape will not be considered transparent geometry (even if there are alpha values < 1) and may not be rendered correctly. You can force Open Inventor to handle the shape as transparent geometry by putting an SoMaterial node with non-zero transparency before it in the scene graph.
  • Normal generation:
    Automatic generation of normal vectors is ONLY enabled when:
  • SoGetPrimitiveCountAction:
    When using the primitive restart feature, the triangle/line count returned by the SoGetPrimitiveCountAction will not be accurate.
  • Concave polygons:
    Unlike (for example) SoFaceSet, SoVolumeBufferedShape does not automatically tesselate concave or complex polygons. Such primitives may not be rendered correctly.
  • SoWriteAction:
    SoVolumeBufferedShape can be saved to and restored from a .iv file just like any other Open Inventor node. However, during the read operation any OpenGL buffer objects (SoGLBufferObject) in the file will be created as CPU buffers (SoCpuBufferObject) if there is no OpenGL context bound during the read operation.
  • Material binding (etc):
    SoVolumeBufferedShape effectively only supports per-vertex and per-vertex-indexed binding of materials, normals and texture coordinates.
  • Simplification:
    SoVolumeBufferedShape is ignored by the "simplify" actions (SoShapeSimplifyAction, SoGlobalSimplifyAction, SoReorganizeAction).

Notes:

  • The volume size and orientation (like geometry) can be modified by transformation nodes in the scene graph and this in turn modifies the appearance of volume rendering nodes like SoVolumeBufferedShape. However the same transformation must be applied to the volume data node and all volume rendering nodes associated with that volume. So effectively any transformation nodes that affect the volume must be placed before the volume data node.
  • Composition with Multiple Data:
    It is possible to compose datasets that have different dimensions, tile sizes and transformations.
    In order to help fetch the correct data values in custom shaders, texture coordinates conversion functions are provided in the VolumeViz/vvizStructure.h shader include.
    For instance,
    vec3 VVizTextureToTextureVec(in VVizDataSetId datasetSrc, in VVizDataSetId datasetDst, in vec3 texCoord);
    vec3 VVizTextureToTextureVec(in VVizDataSetId datasetSrc, in VVizDataSetId datasetDst, in vec3 texCoord)
    Converts the input vector from the texture space of one dataset to the texture space of another datas...
    can be used to convert texture coordinates related to one dataset to texture coordinates related to another dataset.
    The conversion is based solely on the transformations applied to each dataset, which are defined by their model matrix and their extent.
    Please note that the model matrix of a dataset is defined by to the SoTransformation nodes that are placed before the SoDataSet node in the order of the traversal.

FILE FORMAT/DEFAULT

    VolumeBufferedShape {
    clipGeometry TRUE
    offset 0
    interpolation LINEAR
    useNormalsGenerator TRUE
    shapeType TRIANGLES
    numVertices 0
    vertexBuffer NULL
    vertexComponentsCount 3
    vertexComponentsType SbDataType::FLOAT
    vertexStride 0
    vertexOffset 0
    normalBuffer NULL
    normalComponentsType SbDataType::FLOAT
    normalStride 3 * sizeof(float)
    normalOffset 0
    indexBuffer NULL
    indexType SbDataType::UNSIGNED_INT32
    indexOffset 0
    colorBuffer NULL
    colorComponentsType SbDataType::FLOAT
    colorStride 0
    colorOffset 0
    colorComponentsCount 3
    texCoordsBuffer NULL
    texCoordsComponentsType SbDataType::FLOAT
    texCoordsStride 0
    texCoordsOffset 0
    texCoordsComponentsCount 2
    primitiveRestartEnabled FALSE
    primitiveRestartValue -1
    }

ACTION BEHAVIOR

    SoGLRenderAction
    Draws primitives based on the current coordinates, normals, materials, drawing style, and so on.

    SoRayPickAction
    Picks primitives based on the current coordinates and transformation. Details about the intersection are returned in an SoFaceDetail.

    SoGetBoundingBoxAction
    Computes the bounding box that encloses all vertices of the face set with the current transformation applied to them. Sets the center to the real center of the bounding box: center{ (xmax + xmin) / 2, (ymax + ymin) / 2, (zmax + zmin) / 2 }

    SoCallbackAction
    If any triangle callbacks are registered with the action, they will be invoked for each successive triangle generated from each face in the set.

SEE ALSO

SoBufferedShape, SoVolumeData, SoTransferFunction, SoROI, SoVolumeIndexedFaceSet, SoVolumeIndexedTriangleStripSet, SoVolumeTriangleStripSet, SoFaceDetail

Definition at line 276 of file SoVolumeBufferedShape.h.

Constructor & Destructor Documentation

◆ SoVolumeBufferedShape()

SoVolumeBufferedShape::SoVolumeBufferedShape ( )

Constructor.

Member Function Documentation

◆ getClassTypeId()

static SoType SoVolumeBufferedShape::getClassTypeId ( )
static

Returns the type identifier for this class.


◆ getTypeId()

virtual SoType SoVolumeBufferedShape::getTypeId ( ) const
virtual

Returns the type identifier for this specific instance.

Reimplemented from SoBufferedShape.

Member Data Documentation

◆ clipGeometry

SoSFBool SoVolumeBufferedShape::clipGeometry

Specifies to clip the geometry at the volume boundaries.


The SoROI node also affects the clipping process. Default is TRUE.

Definition at line 286 of file SoVolumeBufferedShape.h.

◆ interpolation

SoSFEnum SoVolumeBufferedShape::interpolation

Interpolation mode.

Use enum SoVolumeShape::Interpolation. Default is LINEAR. NOTE: In most cases on modern graphics boards, indexed textures are used, so this refers to interpolation of volume data values.

Definition at line 304 of file SoVolumeBufferedShape.h.

◆ offset

SoSFFloat SoVolumeBufferedShape::offset

Sets an offset value used for computing the texture coordinates.


The texture coordinate for each vertex will be taken from a point offset units away from the vertex. The offset is measured in the direction of the vertex normal. By default the offset is equal to 0 (no offset). When using this feature, a vertex normal must exist for every vertex. If vertex normals are not supplied, Open Inventor will compute vertex normals in the usual way except that the crease angle will be fixed at PI in order to assure that a vertex normal is computed at every vertex.

Definition at line 299 of file SoVolumeBufferedShape.h.


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