Ogre2 Implementation for Lidar Visual

[mihirk284]

Added the Ogre2 implementation for Lidar Visual
Pls see attached screenshots

@iche033
@ahcorde

[ahcorde]

Is there any reason to change this?

[mihirk284]

I did this as LVT_TRIANGLE_STRIPS was the standard visual before ( before we added types, and the only visual in Gazebo Classic), in order to retain the same in the example.

[ahcorde]

Some tests are failing

LidarVisual/LidarVisualTest.RaysUnitBox/ogre (from LidarVisual_LidarVisualTest

LidarVisual/LidarVisualTest.LaserVertical/ogre (from LidarVisual_LidarVisualTest)

[ahcorde]

I tried to add another render engine here

https://github.com/ignitionrobotics/ign-rendering/blob/e22fd80e25aa89454a2be1d69891c83c7900f4c0/examples/lidar_visual/Main.cc#L279

  engineNames.push_back("ogre2");

To be able to change the render engine with Tab, but I'm getting the following error

lidar_visual: /build/ogre-1.9-kiU5_5/ogre-1.9-1.9.0+dfsg1/OgreMain/include/OgreSingleton.h:80: Ogre::Singleton<T>::Singleton() [with T = Ogre::LogManager]: Assertion `!msSingleton' failed.

I know this issue is unrelated but do you mind to have a look ?

[mihirk284]

@ahcorde Regarding the tests, I think this is a known test failure which is happening on Windows with other tests as well. I'm not sure why this is failing on Windows

Even for the previous PRs, the same failure message was seen on Windows

[iche033]

Works well for me.

One minor note: I see this warning msg printed when running the example:

[Wrn] [Ogre2GpuRays.cc:280] Only one vertical ray but vertical min. and max. angle are not equal. Min. angle is used.

[iche033]

lidar_visual: /build/ogre-1.9-kiU5_5/ogre-1.9-1.9.0+dfsg1/OgreMain/include/OgreSingleton.h:80: Ogre::Singleton::Singleton() [with T = Ogre::LogManager]: Assertion `!msSingleton' failed.

Regarding this error when loading ogre2 along side of ogre, I looked into this some time ago and found that it's likely due to symbol collision between the ogre and ogre2 libraries. When ogre1.x is loaded, a few singletons were created, and when switching to ogre 2.x, it tries to create more singletons that collide with the ones that are already in memory. I think the would either need to 1) namespace the ogre singletons (not sure how to do this without editing ogre itself or 2) completely unload ogre 1.x plugin before switching to ogre 2.x at runtime).

I haven't figured out a solution to this issue yet so any help / suggestions welcome.

[Sarath18]

Hey @mihirk284. I was integrating LidarVisual to ign-rviz and found that ClearPoints API doesn't seem to clear the visual that is already been visualized, rather it just clears the internal state and there is no direct API to clear the visual. I went through the ogre LidarVisual code and found a method ClearVisualData but it is not exposed to the user. It will be great if we have a method to clear the visuals.

[iche033]

can you fix DCO? instructions in Details next to the DCO check.

[iche033]

Regarding the ClearVisual and ClearPoints functions, I think it could be confusing for the user of the API of what the differences are. As a user, when I clear or update points, I expect the visual to be updated as well otherwise we end up with inconsistent state between the data and the visualization. How about for the public API of the LidarVisual interface, we offer just the functionClearPoints and internally we clear both the points and the visualization?

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