Non-uniform step, absorption & scattering: inhomogeneous.pxd

Hi there, many thanks as usual for the amazing work! Below is our idea of implementation of non-uniform smapling along the ray direction, alongside absorption and scattering. Changes to the original code are marked by "MMM". More insights are provided in [A. Aimetta, M. Moscheni et al, "Forward modelling of Dα camera view in ST40 informed by experimental data", submitted to Fus. Eng and Des.]. If you have any feedbacks on this, that would be appreciated!

# cython: language_level=3

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from raysect.optical cimport World, Primitive, Ray, Spectrum, Point3D, Vector3D, AffineMatrix3D
from raysect.optical.material.material cimport NullSurface

cdef class VolumeIntegrator:

    cpdef Spectrum integrate(self, Spectrum spectrum, World world, Ray ray, Primitive primitive,
                             InhomogeneousVolumeEmitter material, Point3D start_point, Point3D end_point,
                             AffineMatrix3D world_to_primitive, AffineMatrix3D primitive_to_world)

cdef class NumericalIntegrator(VolumeIntegrator):

    cdef:
        double _step
        int _min_samples

    cdef int _check_dimensions(self, Spectrum spectrum, int bins) except -1
    # MMM
    cdef double _compute_step_sampling(self, InhomogeneousVolumeEmitter material, Point3D point) except -1
    cdef tuple _simulate_scattering(self, InhomogeneousVolumeEmitter material, Point3D point, int num_collisions)

cdef class InhomogeneousVolumeEmitter(NullSurface):

    cdef public VolumeIntegrator integrator

    cpdef Spectrum emission_function(self, Point3D point, Vector3D direction, Spectrum spectrum,
                                     World world, Ray ray, Primitive primitive,
                                     AffineMatrix3D to_local, AffineMatrix3D to_world)

raysect / source

Non-uniform step, absorption & scattering: inhomogeneous.pxd #414