diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/photon.h | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/src/photon.h b/src/photon.h index f76ca54..45ad79b 100644 --- a/src/photon.h +++ b/src/photon.h @@ -179,7 +179,15 @@ __device__ void propagate_at_boundary(Photon &p, State &s, curandState &rng) float refracted_angle = asinf(sinf(incident_angle)*s.refractive_index1/s.refractive_index2); float3 incident_plane_normal = cross(p.direction, s.surface_normal); - incident_plane_normal /= norm(incident_plane_normal); + float incident_plane_normal_length = norm(incident_plane_normal); + + // Photons at normal incidence do not have a unique plane of incidence, + // so we have to pick the plane normal to be the polarization vector + // to get the correct logic below + if (incident_plane_normal_length < 1e-6f) + incident_plane_normal = p.polarization; + else + incident_plane_normal /= incident_plane_normal_length; float normal_coefficient = dot(p.polarization, incident_plane_normal); float normal_probability = normal_coefficient*normal_coefficient; |