Handle non-positive object temperatures

[adlarkin]

Related to gazebosim/gz-sim#621. This handles temperatures that are <= 0 kelvin for the thermal camea.

Signed-off-by: Ashton Larkin ashton@openrobotics.org

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[codecov]

Codecov Report

Merging #243 (3454c14) into ign-rendering4 (7d55d9b) will decrease coverage by 0.01%.
The diff coverage is 62.50%.

@@                Coverage Diff                 @@
##           ign-rendering4     #243      +/-   ##
==================================================
- Coverage           53.50%   53.48%   -0.02%     
==================================================
  Files                 145      145              
  Lines               13753    13760       +7     
==================================================
+ Hits                 7358     7359       +1     
- Misses               6395     6401       +6     

Impacted Files	Coverage Δ
ogre2/src/Ogre2ThermalCamera.cc	89.28% <62.50%> (-1.48%)	⬇️

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[iche033]

I made some tweaks in a3a8854 that clamps neg temperature to 0 and enable our shaders work with 0 temp value. This should make the test in gazebosim/gz-sim#621 pass

[adlarkin]

I made some tweaks in a3a8854 that clamps neg temperature to 0

I just took a look and tested this out, it works for me! I'm marking this as ready for review. If we merge gazebosim/gz-sim#621, this will need to be merged and we will need to make a patch release of ign-rendering before making the related ign-gazebo release.

[adlarkin]

As mentioned in gazebosim/gz-sim#621 (comment), I am holding off on merging this for now since it would effect ign-gazebo and ign-rendering releases that are currently in-process at the time of this writing. I will mark this as a draft and re-open it once the releases are complete.

[nkoenig]

This only clamps the temp value when foundTemp is true. Is it possible for foundTemp to be false and temp to be < 0.0? If so, should you handle that case?

[adlarkin]

Is it possible for foundTemp to be false and temp to be < 0.0?

I don't think so. The only way foundTemp is set to true is if temperature is defined/attached to a visual, which would mean that <temperature> needs to be specified in the SDF file in the ign-gazebo context. If <temperature> is not specified, then this code should run (background object where object colors are used to define temperatures - since we're using rgb here, it shouldn't be possible to have an rgb value that is < 0): https://github.com/ignitionrobotics/ign-rendering/blob/8e0de0dd3e499c0fc0191a2cd8b794b0aab69980/ogre2/src/Ogre2ThermalCamera.cc#L387-L417