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Diffstat (limited to 'doc/source/surface.rst')
| -rw-r--r-- | doc/source/surface.rst | 23 |
1 files changed, 7 insertions, 16 deletions
diff --git a/doc/source/surface.rst b/doc/source/surface.rst index a9b61d1..0ed142b 100644 --- a/doc/source/surface.rst +++ b/doc/source/surface.rst @@ -3,7 +3,7 @@ Surface Models Chroma includes a variety of surface models, which control the interaction of photons with objects. The ``Surface`` class contains many (typically wavelength-dependent) surface parameters, some of which apply to each surface model. -To select a particular model for a surface, set ``surface.model = MODEL`` where ``MODEL`` is one of ``{ SURFACE_DEFAULT, SURFACE_SPECULAR, SURFACE_DIFFUSE, SURFACE_COMPLEX, SURFACE_WLS }``. +To select a particular model for a surface, set ``surface.model = MODEL`` where ``MODEL`` is one of ``{ SURFACE_DEFAULT, SURFACE_COMPLEX, SURFACE_WLS }``. ``SURFACE_DEFAULT`` ------------------- @@ -19,27 +19,17 @@ Parameters:: unsigned int n float step float wavelength0 - -``SURFACE_SPECULAR`` --------------------- - -A perfect specular reflector. Behavior is identical to ``SURFACE_DEFAULT`` with 100% specular reflection at all wavelengths, but is marginally faster. This model has no parameters. - -``SURFACE_DIFFUSE`` -------------------- - -A perfect diffuse reflector. Behavior is identical to ``SURFACE_DEFAULT`` with 100% diffuse reflection at all wavelengths, but is marginally faster. This model has no parameters. ``SURFACE_COMPLEX`` ------------------- -This surface model uses a complex index of refraction (``eta``, ``k``) to compute transmission, (specular) reflection, and absorption probabilities. Surfaces may also be photon detectors, but the detection probability is conditional on detection (``detect`` should be normalized to 1). If a surface is not transmissive (``bool transmissive``), transmitted photons are absorbed. - -This model accounts for incoming photon polarization in its calculations. +This surface model uses a complex index of refraction (``eta``, ``k``) to compute transmission, (specular) reflection, and absorption probabilities, taking into account the incoming photon polarization and surface thickness (``thickness``). Surfaces may also be photon detectors, but detection is conditional on absorption so ``detect`` should be normalized independently. Reflection may be either specular or diffuse, with probabilities given in ``reflect_specular`` and ``reflect_diffuse``; these should sum to 1 at each wavelength. By default surfaces are not transmissive (use ``bool transmissive`` to set), and transmitted photons are absorbed. Parameters:: float *detect + float *reflect_specular + float *reflect_diffuse float *eta float *k unsigned int n @@ -51,12 +41,13 @@ Parameters:: ``SURFACE_WLS`` --------------- -A model of wavelength-shifting surfaces. Surfaces may absorb and reflect (these probabilities should sum to 1). Reflection is diffuse. If a photon is absorbed, it may be reemitted with a probability given in ``float *reemit`` (normalized to 1). The reemission spectrum CDF is defined in ``float* reemission_cdf``. The CDF must start at 0 and end at 1. This model does not enforce conservation of energy, and cannot reemit multiple photons! +This surface model is used for wavelength-shifting surfaces. Surfaces may absorb, specularly reflect, diffusely reflect, or transmit photons; ``1 - absorb - reflect_diffuse - reflect_specular`` gives the transmission probability. If a photon is absorbed, it may be reemitted with a probability given in ``float *reemit``. The reemission spectrum CDF is defined in ``float* reemission_cdf``. The CDF must start at 0 and end at 1. This model does not enforce conservation of energy, and cannot reemit multiple photons! Parameters:: float *absorb - float *reflect + float *reflect_specular + float *reflect_diffuse float *reemit float *reemission_cdf unsigned int n |