Fix projector FOV, orientation, and crashes

[iche033]

🦟 Bug fix

Summary

Fix a number of issues with projector

• Fixed FOV calculation - int division issue
• Fixed orientation - it was upside down
• Fixes crashes
  • on exit in the destructor
  • when heightmaps are in the scene - the ogre2 generated shaders didn't compile

Test it

Can be tested with the harmonic demo: gazebosim/harmonic_demo#10
The expected result is shown in the screenshot in that pull request. Without these changes, the harmonic demo will crash on launch.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[codecov]

Codecov Report

Merging #913 (b5e5076) into gz-rendering8 (8c1fd27) will decrease coverage by 0.02%.
Report is 1 commits behind head on gz-rendering8.
The diff coverage is 60.00%.

❗ Current head b5e5076 differs from pull request most recent head 5362088. Consider uploading reports for the commit 5362088 to get more accurate results

@@                Coverage Diff                @@
##           gz-rendering8     #913      +/-   ##
=================================================
- Coverage          75.18%   75.16%   -0.02%     
=================================================
  Files                177      177              
  Lines              16846    16849       +3     
=================================================
  Hits               12665    12665              
- Misses              4181     4184       +3     

Files Changed	Coverage Δ
ogre2/src/Ogre2RenderEngine.cc	68.18% <ø> (ø)
ogre2/src/Ogre2Projector.cc	70.86% <60.00%> (-0.91%)	⬇️

... and 1 file with indirect coverage changes