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| author | Stan Seibert <stan@mtrr.org> | 2011-12-21 11:28:57 -0500 |
|---|---|---|
| committer | tlatorre <tlatorre@uchicago.edu> | 2021-05-09 08:42:38 -0700 |
| commit | 04400903076e88d99cdd769de5504d7e259a1ffe (patch) | |
| tree | 3499b4f31e3352162c38363518b61066334998a5 /chroma/cuda | |
| parent | 29350829b9c4c2759aeb010da7d6f6d08687bf5d (diff) | |
| download | chroma-04400903076e88d99cdd769de5504d7e259a1ffe.tar.gz chroma-04400903076e88d99cdd769de5504d7e259a1ffe.tar.bz2 chroma-04400903076e88d99cdd769de5504d7e259a1ffe.zip | |
Allow for option of forced scattering or forced non-scattering on the first step during photon propagation.
Diffstat (limited to 'chroma/cuda')
| -rw-r--r-- | chroma/cuda/photon.h | 31 | ||||
| -rw-r--r-- | chroma/cuda/propagate.cu | 5 |
2 files changed, 33 insertions, 3 deletions
diff --git a/chroma/cuda/photon.h b/chroma/cuda/photon.h index 79a87f0..371c122 100644 --- a/chroma/cuda/photon.h +++ b/chroma/cuda/photon.h @@ -180,7 +180,7 @@ rayleigh_scatter(Photon &p, curandState &rng) } // scatter __device__ int propagate_to_boundary(Photon &p, State &s, curandState &rng, - bool use_weights=false) + bool use_weights=false, int scatter_first=0) { float absorption_distance = -s.absorption_length*logf(curand_uniform(&rng)); float scattering_distance = -s.scattering_length*logf(curand_uniform(&rng)); @@ -190,6 +190,35 @@ __device__ int propagate_to_boundary(Photon &p, State &s, curandState &rng, else use_weights = false; + if (scatter_first == 1) { + // Force scatter + float scatter_prob = 1.0f - expf(-s.distance_to_boundary/s.scattering_length); + + if (scatter_prob > WEIGHT_LOWER_THRESHOLD) { + int i=0; + const int max_i = 1000; + while (i < max_i && scattering_distance > s.distance_to_boundary) { + scattering_distance = -s.scattering_length*logf(curand_uniform(&rng)); + i++; + } + p.weight *= scatter_prob; + } + + } else if (scatter_first == -1) { + // Prevent scatter + float no_scatter_prob = expf(-s.distance_to_boundary/s.scattering_length); + + if (no_scatter_prob > WEIGHT_LOWER_THRESHOLD) { + int i=0; + const int max_i = 1000; + while (i < max_i && scattering_distance <= s.distance_to_boundary) { + scattering_distance = -s.scattering_length*logf(curand_uniform(&rng)); + i++; + } + p.weight *= no_scatter_prob; + } + } + if (absorption_distance <= scattering_distance) { if (absorption_distance <= s.distance_to_boundary) { p.time += absorption_distance/(SPEED_OF_LIGHT/s.refractive_index1); diff --git a/chroma/cuda/propagate.cu b/chroma/cuda/propagate.cu index 29f8aea..9520cf8 100644 --- a/chroma/cuda/propagate.cu +++ b/chroma/cuda/propagate.cu @@ -116,7 +116,7 @@ propagate(int first_photon, int nthreads, unsigned int *input_queue, float *wavelengths, float3 *polarizations, float *times, unsigned int *histories, int *last_hit_triangles, float *weights, - int max_steps, int use_weights, + int max_steps, int use_weights, int scatter_first, Geometry *g) { __shared__ Geometry sg; @@ -171,7 +171,8 @@ propagate(int first_photon, int nthreads, unsigned int *input_queue, if (p.last_hit_triangle == -1) break; - command = propagate_to_boundary(p, s, rng, use_weights); + command = propagate_to_boundary(p, s, rng, use_weights, scatter_first); + scatter_first = 0; // Only use the scatter_first value once if (command == BREAK) break; |