add ellipsoid shape to pcl_visualizer

[Yosshi999]

Implemented addEllipsoid

Visualization sample: visualize the voxel grid covariances for Bunny

[JStech]

LGTM

[mvieth]

Thank you for this!
I am not totally sure that the order in which translation and rotation are applied is the order one would expect. Perhaps using Eigen::Isometry3f instead of translation and rotation would leave less room for interpretation and make it less ambiguous?

[Yosshi999]

According to the documentation,

Most of the methods for manipulating this transformation, e.g. Translate, Rotate, and Concatenate, can operate in either PreMultiply (the default) or PostMultiply mode. In PreMultiply mode, the translation, concatenation, etc. will occur before any transformations which are represented by the current matrix. In PostMultiply mode, the additional transformation will occur after any transformations represented by the current matrix.

the vtk's default mode is PreMultiply, so I think its order is common (I mean, vtk will perform rotation and then translation.)
But it is good idea to use Isometry3f for its arguments.

(Edit)
Or it may be less ambiguous if "orientation" is used instead of "rotation" for the name of that argument. What do you think about this?

[mvieth]

Thanks for pinging me.
I am still not so sure about translation+rotation vs Eigen::Isometry. If a user calls createEllipsoid (or addEllipsoid, which calls createEllipsoid), it might not be clear whether the translation is applied first or the rotation. I think usually the rotation would be applied first, then the translation, but here it is the other way around, right?
So if there are only versions of createEllipsoid and addEllipsoid that receive an Isometry transformation as a parameter, that would IMO be totally unambiguous. Internally, you could get the 4x4 transformation matrix from the Eigen Isometry object with matrix(), or maybe with data(), and use the SetMatrix function of vtkTransform (possibly with some conversion steps in between). What do you think?

[Yosshi999]

@mvieth
At first I tried to imitate the arguments of addCube, but I agree with your idea. I'll remove translation+rotation version.

Internally, you could get the 4x4 transformation matrix from the Eigen Isometry object with matrix(), or maybe with data(), and use the SetMatrix function of vtkTransform

I will check it, thank you!

[Yosshi999]

Undefined symbols for architecture x86_64:
  "vtkParametricEllipsoid::New()", referenced from:
      pcl::visualization::createEllipsoid(Eigen::Transform<double, 3, 1, 0> const&, double, double, double) in shapes.cpp.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [lib/libpcl_visualization.1.11.1.99.dylib] Error 1
make[1]: *** [visualization/CMakeFiles/pcl_visualization.dir/all] Error 2

I have no idea to resolve this...

[larshg]

For VTK9 you have to link more specific libraries, as all is not included by default.

You'll have to add CommonComputationalGeometry to the list of required libraries in CMakeList of visualization.

[larshg]

You need to add it here as well.

pcl/visualization/CMakeLists.txt

Lines 168 to 170 in 7ca2d32

	target_link_libraries("${LIB_NAME}"
	VTK::ChartsCore
	VTK::CommonColor

[kunaltyagi]

The changes LGTM (Though I'm wondering if VTK also has modules which might be non-default on some platforms and we can accidentally break them by adding a dependency in PCL)

[mvieth]

Thanks!
@kunaltyagi Regarding the possible VTK dependency problem: not really much we can do about that, right? Just waiting and seeing if someone reports a problem

[kunaltyagi]

That's correct. Just pointing out something that stood out to me (apart from the PR, nice work @Yosshi999 )