htrdr

commit 59fde9035d6ae2b725eeabfba1208566053e8a86
parent a535d68dc5bdaa31ac36feed38a026ba4d89e4aa
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Tue, 19 Mar 2019 10:24:16 +0100

Merge branch 'release_0.0.4'

Diffstat:
M
README.md
 | 
12
++++++++++++
M
cmake/CMakeLists.txt
 | 
2
+-
M
src/htrdr.c
 | 
4
+++-
M
src/htrdr_compute_radiance_sw.c
 | 
10
++++++----

4 files changed, 22 insertions(+), 6 deletions(-)
diff --git a/README.md b/README.md
@@ -60,6 +60,18 @@ informations on CMake.
 
 ## Release notes
 
+### Version 0.0.4
+
+- Fix the computation of the surface scattering: there was a bug in how Russian
+  roulette was implemented at surface scattering leading to an underestimation
+  of the surface reflection.
+- Update the thread allocation policy: by default, the number of threads is now
+  defined as the maximum between the number of processors detected by OpenMP
+  and the number of threads defined by the `OMP_NUM_THREADS` environment
+  variable. This variable can be used to counteract the number of processors
+  detected by OpenMP that can be lower than the real number of processors of
+  the system.
+
 ### Version 0.0.3
 
 - Fix compilation on systems with a GNU C Library whose version is less than
diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
@@ -60,7 +60,7 @@ include_directories(
 ################################################################################
 set(VERSION_MAJOR 0)
 set(VERSION_MINOR 0)
-set(VERSION_PATCH 3)
+set(VERSION_PATCH 4)
 set(VERSION ${VERSION_MAJOR}.${VERSION_MINOR}.${VERSION_PATCH})
 
 set(HTRDR_ARGS_DEFAULT_CAMERA_POS "0,0,0")
diff --git a/src/htrdr.c b/src/htrdr.c
@@ -437,6 +437,7 @@ htrdr_init
   double sun_dir[3];
   const char* output_name = NULL;
   size_t ithread;
+  int nthreads_max;
   res_T res = RES_OK;
   ASSERT(args && htrdr);
 
@@ -451,10 +452,11 @@ htrdr_init
 
   str_init(htrdr->allocator, &htrdr->output_name);
 
+  nthreads_max = MMAX(omp_get_max_threads(), omp_get_num_procs());
   htrdr->dump_vtk = args->dump_vtk;
   htrdr->cache_grids = args->cache_grids;
   htrdr->verbose = args->verbose;
-  htrdr->nthreads = MMIN(args->nthreads, (unsigned)omp_get_num_procs());
+  htrdr->nthreads = MMIN(args->nthreads, (unsigned)nthreads_max);
   htrdr->spp = args->image.spp;
   htrdr->width = args->image.definition[0];
   htrdr->height = args->image.definition[1];
diff --git a/src/htrdr_compute_radiance_sw.c b/src/htrdr_compute_radiance_sw.c
@@ -325,6 +325,7 @@ htrdr_compute_radiance_sw
   /* Radiative random walk */
   for(;;) {
     struct scattering_context scattering_ctx = SCATTERING_CONTEXT_NULL;
+    double bounce_reflectivity = 0;
 
     /* Find the first intersection with a surface */
     d2(range, 0, DBL_MAX);
@@ -388,16 +389,14 @@ htrdr_compute_radiance_sw
 
     /* Scattering at a surface */
     if(SVX_HIT_NONE(&svx_hit)) {
-      double reflectivity;
       double N[3];
       int type;
 
       d3_normalize(N, d3_set_f3(N, s3d_hit.normal));
       if(d3_dot(N, wo) < 0) d3_minus(N, N);
-      reflectivity = ssf_bsdf_sample
-        (bsdf, rng, wo, N, dir_next, &type, &pdf);
-      if(ssp_rng_canonical(rng) > reflectivity) break; /* Russian roulette */
 
+      bounce_reflectivity = ssf_bsdf_sample
+        (bsdf, rng, wo, N, dir_next, &type, &pdf);
       if(d3_dot(N, sun_dir) < 0) { /* Below the ground */
         R = 0;
       } else {
@@ -432,6 +431,9 @@ htrdr_compute_radiance_sw
     ksi *= Tr_abs;
     w += ksi * L_sun * sun_solid_angle * Tr * R;
 
+    /* Russian roulette */
+    if(ssp_rng_canonical(rng) >= bounce_reflectivity) break;
+
     /* Setup the next random walk state */
     d3_set(pos, pos_next);
     d3_set(dir, dir_next);