SoVolumeDetail Class Reference
[Details]
Base class for detail information about picking in a data volume.
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#include <VolumeViz/details/SoVolumeDetail.h>
Public Member Functions | |
| virtual SoType | getTypeId () const |
| SoVolumeDetail () | |
| virtual | ~SoVolumeDetail () |
| void | getProfileObjectPos (SbVec3f profile[2]) const |
| int | getProfileDataPos (SbVec3i32 profile[2]) const |
| int64_t | getProfileValue (int index, SbVec3i32 &pos, SbVec3f *objPos=0, SbBool realValue=FALSE) const |
| double | getProfileValueD (int index, SbVec3i32 &pos, SbVec3f *objPos, SbBool realValue=FALSE) const |
| virtual SbBool | getFirstNonTransparentValue (int64_t &value, SbVec3i32 &pos, SbVec3f *objPos=0, SbBool realValue=FALSE) const |
| virtual SbBool | getFirstNonTransparentValue (double &value, SbVec3i32 &pos, SbVec3f *objPos=0, SbBool realValue=FALSE) const |
| virtual SoDetail * | copy () const |
Static Public Member Functions | |
| static SoType | getClassTypeId () |
Detailed Description
Base class for detail information about picking in a data volume.
A successful pick operation returns an SoPickedPoint object. If the picked geometry is an SoVolumeSkin or SoVolumeRender, use the getDetail method and cast the result to the appropriate class (SoVolumeSkinDetail or SoVolumeRenderDetail) to get extra information about the location of the pick.
SoVolumeDetail returns information about the first (closest) non-transparent voxel along the pick ray and/or information about all the voxels intersected by the pick ray (called a profile). For the first non-transparent voxel (if any) on the pick ray, it returns XYZ position, IJK location, and data value. For the profile defined by all the intersected voxels, it returns:
- Profile position in object space (two XYZ points)
- Profile location in the data volume (two IJK indices)
- Number of values along the profile
- Each voxel value and corresponding IJK location
This class returns information about the data values in the picked voxels. SoVolumeRenderDetail also returns information about the mapped RGBA colors of the picked voxels.
GPU picking vs. CPU picking
- VolumeViz can compute the picked voxel(s) and voxel colors on the GPU.
GPU picking is generally faster than CPU picking, but more importantly it is the only way to be sure of getting the correct result if the application is using a custom shader (see SoVolumeShader and VVizComputeFragmentColor) to compute voxel color and opacity. CPU picking always uses the color and opacity values assigned by the SoTransferFunction node. Therefore the result should be the same when using SoTransferFunction to assign color and opacity, but when using a custom shader the CPU picking algorithm is not able to know the color and opacity assigned by the shader.
- Important: To enable GPU picking
- The realValue parameter must be false when calling the getXXX methods.
- The SoRayPickAction must be aware of the SoSceneManager.
SoHandleEventAction does this automatically, so it is not necessary for the application to take any action when using an SoEventCallback node and calling the getPickedPoint() method. However if the application creates its own instance of SoRayPickAction, then it must call the method SoAction::setSceneManager() on that instance. If the scene manager is not specified, a warning message is issued and CPU picking is done.
- The realValue parameter must be false when calling the getXXX methods.
- Also be aware of the following trade-off. If the realValue parameter is set to false, the voxel value returned may be based on lower resolution (sub-sampled) data. The values should be approximately the same, but to be sure of getting values from the full resolution data, set the realValue parameter to true.
Limitations:
- If multiple volumes are being combined under an SoMultiDataSeparator, the detail class only returns values for the first volume in the scene graph.
- Because picking returns actual values of voxel, there may be a small difference between what you see on screen and what you get with picking. When visualizing a volume using LINEAR or CUBIC interpolation, you visualize interpolated data. Picking returns informations such as voxel value, voxel postion, etc... so picking return information of voxel values, not interpolated one. Visible areas may be not pickable and unvisibke areas may be pickable. When using NEAREST interpolation for rendering, picking matches what is displayed.
SEE ALSO
SoDetail, SoFenceSliceDetail, SoVolumeRenderDetail, SoVolumeSkinDetail, SoVolumeRender, SoVolumeSkin
Constructor & Destructor Documentation
| SoVolumeDetail::SoVolumeDetail | ( | ) |
Constructor.
| virtual SoVolumeDetail::~SoVolumeDetail | ( | ) | [virtual] |
Destructor.
Member Function Documentation
| virtual SoDetail* SoVolumeDetail::copy | ( | ) | const [virtual] |
Returns an instance that is a copy of this instance. The caller is responsible for deleting the copy when it is no longer needed.
Implements SoDetail.
Reimplemented in SoFenceSliceDetail, SoVolumeRenderDetail, and SoVolumeSkinDetail.
| static SoType SoVolumeDetail::getClassTypeId | ( | ) | [static] |
Returns the type identifier for this class.
Reimplemented from SoDetail.
Reimplemented in SoFenceSliceDetail, SoVolumeRenderDetail, and SoVolumeSkinDetail.
| virtual SbBool SoVolumeDetail::getFirstNonTransparentValue | ( | double & | value, | |
| SbVec3i32 & | pos, | |||
| SbVec3f * | objPos = 0, |
|||
| SbBool | realValue = FALSE | |||
| ) | const [virtual] |
Returns the floating point value of the first non-transparent voxel along the pick ray (if any) and its position in object and data space.
Returns FALSE if not found.
If the realValue parameter is TRUE, VolumeViz will return the actual voxel value from the full resolution data. Note that this may require a read from disk if full resolution data is not currently in memory. If FALSE, VolumeViz will return the voxel value from the (possibly subsampled) data currently in memory.
- Warning:
- To use GPU picking, you must specify realValue = FALSE.
| virtual SbBool SoVolumeDetail::getFirstNonTransparentValue | ( | int64_t & | value, | |
| SbVec3i32 & | pos, | |||
| SbVec3f * | objPos = 0, |
|||
| SbBool | realValue = FALSE | |||
| ) | const [virtual] |
Returns the integer value of the first non-transparent voxel along the pick ray (if any) and its position in object and data space.
Returns FALSE if not found.
If the realValue parameter is TRUE, VolumeViz will return the actual voxel value from the full resolution data. Note that this may require a read from disk if full resolution data is not currently in memory. If FALSE, VolumeViz will return the voxel value from the (possibly subsampled) data currently in memory.
- Warning:
- To use GPU picking, you must specify realValue = FALSE.
| int SoVolumeDetail::getProfileDataPos | ( | SbVec3i32 | profile[2] | ) | const |
Returns the number of values along the profile and the profile position in data space (voxel coordinates).
Specifically the profile parameter contains the IJK coordinates of the first and last points on the profile. The number of values is the number of of voxels intersected by the pick ray.
| void SoVolumeDetail::getProfileObjectPos | ( | SbVec3f | profile[2] | ) | const |
Returns the profile position in object space (world coordinates).
Specifically the profile parameter contains the XYZ coordinates of the first and last points on the profile.
| int64_t SoVolumeDetail::getProfileValue | ( | int | index, | |
| SbVec3i32 & | pos, | |||
| SbVec3f * | objPos = 0, |
|||
| SbBool | realValue = FALSE | |||
| ) | const |
Returns the index'th value (as an integer) and its position in object and data space.
The number of values along the profile can be queried using the getProfileDataPos() method. However index is automatically clamped to the valid range of values.
If realValue is TRUE, VolumeViz will return the actual voxel value from the full resolution data. Note that this may require a read from disk if full resolution data is not currently in memory. If FALSE, VolumeViz will return the voxel value from the (possibly subsampled) data currently in memory.
- Warning:
- To use GPU picking, you must specify realValue = FALSE.
| double SoVolumeDetail::getProfileValueD | ( | int | index, | |
| SbVec3i32 & | pos, | |||
| SbVec3f * | objPos, | |||
| SbBool | realValue = FALSE | |||
| ) | const |
Returns the index'th value (as a double) and its position in object and data space.
The number of values along the profile can be queried using the getProfileDataPos() method. However index is automatically clamped to the valid range of values.
If realValue is TRUE, VolumeViz will return the actual voxel value from the full resolution data. Note that this may require a read from disk if full resolution data is not currently in memory. If FALSE, VolumeViz will return the voxel value from the (possibly subsampled) data currently in memory.
- Warning:
- To use GPU picking, you must specify realValue = FALSE.
| virtual SoType SoVolumeDetail::getTypeId | ( | ) | const [virtual] |
Returns the type identifier for this specific instance.
Implements SoTypedObject.
Reimplemented in SoFenceSliceDetail, SoVolumeRenderDetail, and SoVolumeSkinDetail.
The documentation for this class was generated from the following file:
- VolumeViz/details/SoVolumeDetail.h