com.openinventor.volumeviz.nodes

Class SoOffscreenVolumeRender

java.lang.Object

com.openinventor.inventor.Inventor

com.openinventor.inventor.misc.SoBase

com.openinventor.inventor.fields.SoFieldContainer

com.openinventor.inventor.nodes.SoNode

com.openinventor.volumeviz.nodes.SoOffscreenVolumeRender

All Implemented Interfaces:

SafeDisposable

public abstract class SoOffscreenVolumeRender
extends SoNode

Extract data from an SoVolumeRender. The SoOffscreenVolumeRender node extracts data by rendering one or more volumes (via SoVolumeRender) into a buffer that can then be used for different computation tasks.

Volumes of interest are specified by a subscenegraph in volumerenderSceneGraph.

The region to be extracted is the bounding box of the scene graph specified in the bboxSceneGraph field.

To implement an extraction, the application must derive a new class from SoOffscreenVolumeRender and implement :

• the boxComputed method. This method is called with parameters that give access to information about the processed box.
• the getNextSubBox method. This method must return subBox size smaller than getMaxBoxSize. We recommend to request subbox even smaller in order to get more parallelism between extraction processing (done on GPU) and application processing and reduce peak GPU memory resources used.

The resolution of the extraction is controlled by boxSize field. As extraction is done using GPU techniques, there is a size limit on the boxSize that can be extract in one call. This limit can be retreived through getMaxBoxSize call.

Limitations:

• It is not possible to extract a volume displayed as an isosurface (via SoVolumeDataDrawStyle or SoVolumeIsosurface).
• SoResetTransform node usage should be avoided in volumeRenderSceneGraph or bboxSceneGraph scene graph, in order to get the best extraction precision even with very flat extraction box. In general it is possible to use SoTransformSeparator node instead.

File format/default:

SoOffscreenVolumeRender {

volumerenderSceneGraph	NULL
bboxSceneGraph	NULL
boxSize	(64, 64, 64)
trigger	false
opacityThreshold	0
components	ALPHA

}

See also:

SoDataSet, SoVolumeData, SoVolumeRender

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SoOffscreenVolumeRender.ComponentsType

Nested classes/interfaces inherited from class com.openinventor.inventor.Inventor

Inventor.ConstructorCommand

Field Summary

Fields

Modifier and Type	Field and Description
static int	ALPHA Deprecated. Use SoOffscreenVolumeRender.ComponentsType.ALPHA instead.
SoSFNode	bboxSceneGraph Head of the scene graph that defines the 3D off-screen scene cube to consider in world coordinates.
SoSFVec3i32	boxSize Resolution of the output data in the off-screen box.
SoSFEnum<SoOffscreenVolumeRender.ComponentsType>	components Components to get back from the offscreen render.
SoSFMatrix	dataSpaceMatrix This transformation is applied on the volume render texture coordinate during the extraction.
SoSFFloat	opacityThreshold During extraction, voxels with an opacity less than the specified value will be ignored Default is 0.
static int	RGBA Deprecated. Use SoOffscreenVolumeRender.ComponentsType.RGBA instead.
SoSFBool	trigger Setting this field to true will start the off-screen rendering process.
SoSFNode	volumerenderSceneGraph Head of the scene graph that contains one or multiple VolumeRender node to render in 3D off-screen cube.

Fields inherited from class com.openinventor.inventor.Inventor

VERBOSE_LEVEL, ZeroHandle

Method Summary

Modifier and Type	Method and Description
SbVec3i32	getMaxBoxSize() Calls getMaxBoxSize((com.openinventor.inventor.misc.SoState)null).
SbVec3i32	getMaxBoxSize(SoState state) Returns the maximum boxSize that can be extract in one boxComputed for the current state.
SbBox3d	ijkToXyzBox(SbBox3i32 ijkBox) Convert ijk box coordinates returned by boxComputed method to the bboxSceneGraph space.
boolean	synchronousExtraction(SoSceneManager sceneManager) Does extraction synchronously, whereas using trigger field will execute extraction on next redraw.

Methods inherited from class com.openinventor.inventor.nodes.SoNode

affectsState, callback, copy, copy, distribute, doAction, getAlternateRep, getBoundingBox, getByName, getMatrix, getPrimitiveCount, getRenderUnitID, GLRender, GLRenderBelowPath, GLRenderInPath, GLRenderOffPath, grabEventsCleanup, grabEventsSetup, handleEvent, isBoundingBoxIgnoring, isOverride, pick, rayPick, search, setOverride, touch, write

Methods inherited from class com.openinventor.inventor.fields.SoFieldContainer

copyFieldValues, copyFieldValues, enableNotify, fieldsAreEqual, get, getAllFields, getEventIn, getEventOut, getField, getFieldName, hasDefaultValues, isNotifyEnabled, set, setToDefaults

Methods inherited from class com.openinventor.inventor.misc.SoBase

dispose, getEXTERNPROTO, getName, getPROTO, isDisposable, isSynchronizable, setName, setSynchronizable

Methods inherited from class com.openinventor.inventor.Inventor

getAddress, getNativeResourceHandle, startInternalThreads, stopInternalThreads

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ALPHA

@Deprecated
public static final int ALPHA

Deprecated. Use SoOffscreenVolumeRender.ComponentsType.ALPHA instead.

RGBA

@Deprecated
public static final int RGBA

Deprecated. Use SoOffscreenVolumeRender.ComponentsType.RGBA instead.

volumerenderSceneGraph

public final SoSFNode volumerenderSceneGraph

Head of the scene graph that contains one or multiple VolumeRender node to render in 3D off-screen cube.

bboxSceneGraph

public final SoSFNode bboxSceneGraph

Head of the scene graph that defines the 3D off-screen scene cube to consider in world coordinates.

boxSize

public final SoSFVec3i32 boxSize

Resolution of the output data in the off-screen box.

trigger

public final SoSFBool trigger

Setting this field to true will start the off-screen rendering process. This field is set to false when computation is finished. Default is false.

opacityThreshold

public final SoSFFloat opacityThreshold

During extraction, voxels with an opacity less than the specified value will be ignored Default is 0. Valid range is [0-1].

components

public final SoSFEnum<SoOffscreenVolumeRender.ComponentsType> components

Components to get back from the offscreen render. . Default is ALPHA.

dataSpaceMatrix

public final SoSFMatrix dataSpaceMatrix

This transformation is applied on the volume render texture coordinate during the extraction. It allows to change the extraction frame. This matrix is applied on normalized texture coordinates all components are between 0-1 and must be in [0-1] after the transformation. So to inverse an axis, we must apply the following transformation: -1*u+1 (where u is a texture coordinate) and not just a simple negative scale.

To swap I and J axis, the matrix would be:

 SbMatrix( 0, 1, 0, 0,
           1, 0, 0, 0,
           0, 0, 1, 0,
           0, 0, 0, 1);

To reverse I axis, the matrix would be:

 SbMatrix(-1, 0, 0, 0,
           0, 1, 0, 0,
           0, 0, 1, 0,
           1, 0, 0, 1);

To reverse J axis, the matrix would be:

 SbMatrix( 1, 0, 0, 0,
           0,-1, 0, 0,
           0, 0, 1, 0,
           0, 1, 0, 1);

To reverse K axis, the matrix would be:

 SbMatrix( 1, 0, 0, 0,
           0, 1, 0, 0,
           0, 0, -1, 0,
           0, 0, 1, 1);

Method Detail

getMaxBoxSize

public SbVec3i32 getMaxBoxSize()

Calls getMaxBoxSize((com.openinventor.inventor.misc.SoState)null).

synchronousExtraction

public boolean synchronousExtraction(SoSceneManager sceneManager)

Does extraction synchronously, whereas using trigger field will execute extraction on next redraw.

Parameters:

sceneManager - the scene manager of the viewer scene to be extracted.

Returns:

true on success.

getMaxBoxSize

public SbVec3i32 getMaxBoxSize(SoState state)

Returns the maximum boxSize that can be extract in one boxComputed for the current state.

ijkToXyzBox

public SbBox3d ijkToXyzBox(SbBox3i32 ijkBox)

Convert ijk box coordinates returned by boxComputed method to the bboxSceneGraph space.