Point clouds for RGBD cameras

[chapulina]

Needs:

• Move package to subfolder, add metapackage #16
• https://bitbucket.org/ignitionrobotics/ign-sensors/pull-requests/70/
• https://bitbucket.org/ignitionrobotics/ign-gazebo/pull-requests/356/
• https://bitbucket.org/ignitionrobotics/ign-gazebo/pull-requests/351/

---

Current status: publishes PointCloud2 without color information:

[chapulina]

Colors fixed in faa07bd, but I'm not sure why I had to do BGR instead of RGB when populating the point cloud. I checked that the ignition::rendering::Image and the sensor_msgs::Image are storing RGB, but that seems to be swapped from the PointCloud2 message. I'm still investigating, but this is usable and I think all other PRs can be merged.

Note also that the color seems to be slightly offset with respect to the points:

[chapulina]

This is ready for review.

I think the offset between the depth and RGB images is coming from ign-rendering. Note how the falling cone's position is slightly different in the depth and color images:

[scpeters]

I'm going to rebase this on meta_pkg

[azeey]

Works great! I left some comments that should be easily addressed.

[chapulina]

Thanks for the review, @azeey , I think I've addressed all your comments.

[azeey]

Looks like CI is failing because we added ignition packages to package.xml. Would doing rosdep -r help? Otherwise, we might have to revert those changes 🙁

[IeiuniumLux]

@azeey how about #18?

[azeey]

I just tested with ogre vs ogre2 with a 1920x1080 rgbd camera. The weird offset thing you mentioned is much more visible in higher resolution in ogre2, but it doesn't happen in ogre.

Ogre2

Ogre

[scpeters]

CI is 💚

[azeey]

I don't think the offset issue is caused by this PR so I'm good with merging this.

[chapulina]

Nice catch with ogre vs ogre2, @azeey . We can debug more on the ign-rendering side.

[iche033]

for ogre2, do you know if it's the depth data that are at an offset or the color data?

[chapulina]

@iche033 , taking ogre1 as ground truth, depth seems to be the wrong one. It seems to be a bit more zoomed in:

[iche033]

thanks that's helpful. I'm looking into it

[iche033]

issue should be fixed by ign-rendering pull request 173:

https://bitbucket.org/ignitionrobotics/ign-rendering/pull-requests/173