New surfaces module

[mkelley]

New surfaces module, addressing the first step in issue #415.

This PR defines the API for surfaces via the Surface class, and provides support for sunlight scattering off a Lambertian surface:

• Instances of the Surface class require four methods:
  • absorptance(i)
  • emittance(e, phi)
  • reflectance(i, e, phi)
  • radiance(F_i, i, e, phi)
• The provided LambertianSurface class defines absorptance, emittance, and reflectance for a surface that uniformly scatters light in all directions.
• ScatteredLight defines radiance for a surface scattering a light source.
• The ScatteredSunlight adds scattered_sunlight, which is used to calculate the radiance from a surface scattering sunlight. It is mainly for user convenience.

See the documentation for more.

I'm open to any suggestions, especially if improvements in the names and terminology are needed.

[pep8speaks]

Hello @mkelley! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

• In the file sbpy/surfaces/scattered.py:

Line 109:63: E203 whitespace before ':'
Line 119:59: E203 whitespace before ':'

Comment last updated at 2025-01-15 13:22:57 UTC

[github-actions]

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[codecov]

Codecov Report

Attention: Patch coverage is 28.85572% with 143 lines in your changes missing coverage. Please review.

Project coverage is 27.55%. Comparing base (5a3f9be) to head (5315e23).

Files with missing lines	Patch %	Lines
sbpy/surfaces/tests/test_surface.py	0.00%	56 Missing ⚠️
sbpy/surfaces/tests/test_scattered.py	0.00%	28 Missing ⚠️
sbpy/surfaces/tests/test_lambertian.py	0.00%	27 Missing ⚠️
sbpy/surfaces/surface.py	60.00%	14 Missing ⚠️
sbpy/surfaces/scattered.py	58.33%	10 Missing ⚠️
sbpy/surfaces/lambertian.py	61.11%	7 Missing ⚠️
sbpy/units/typing.py	90.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #418       +/-   ##
===========================================
- Coverage   83.15%   27.55%   -55.60%     
===========================================
  Files          88       96        +8     
  Lines        8197     8398      +201     
===========================================
- Hits         6816     2314     -4502     
- Misses       1381     6084     +4703     

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