Support setting the background color for sensors

[nkoenig]

Signed-off-by: Nate Koenig [email protected]

🎉 New feature

The RenderUtil::SetBackgroundColor and RenderUtil::SetAmbientLight were not useful since the values would always be overwritten by the value in the SDF <scene> element, which is guaranteed to be present. The made it impossible for a system plugin to change/override the background color and ambient light used by sensors.

Here is a concrete use-case:

I have a world that was used to generate a log file. I want to replay the log file, and record a video use a camera sensor along with a different background color such as white instead of black.

This change will continue to use the values in the SDF element, unless someone specifies values in the sensor system plugin.

Test it

A test has been added. Feel free to try it.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
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[codecov]

Codecov Report

Merging #1147 (280383d) into ign-gazebo3 (63decda) will not change coverage.
The diff coverage is n/a.

@@             Coverage Diff              @@
##           ign-gazebo3    #1147   +/-   ##
============================================
  Coverage        77.45%   77.45%           
============================================
  Files              222      222           
  Lines            12758    12758           
============================================
  Hits              9882     9882           
  Misses            2876     2876           

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[iche033]

this works for me as advertised.

So now we have 3 ways of changing background color:

• Scene3D's <background_color>: affects GUI
• <scene><background>: affects sensors
• sensors system's <background_color>: affects sensors and overrides <scene><background>

For your use case, is it not an option to just change the <scene><background> color?

[nkoenig]

this works for me as advertised.

So now we have 3 ways of changing background color:

• Scene3D's <background_color>: affects GUI
• <scene><background>: affects sensors
• sensors system's <background_color>: affects sensors and overrides <scene><background>

For your use case, is it not an option to just change the <scene><background> color?

I can't change the SDF's <scene><background> because it's contained in the log file that I'm re-playing.