htrdr

commit 82a7b2e8552adde24bbb90d82845a20383fb32ab
parent c565ae49a99be1f1466f3708ea50e7355192123d
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Fri,  9 Dec 2022 16:14:43 +0100

planeto: add support of discrete distribution of wavelengths

In shortwave, if spectrally variable radiance is defined on the source,
wavelengths are sampled from this data.

Diffstat:
M
src/planeto/htrdr_planeto.c
 | 
53
+++++++++++++++++++++++++++++++++++++++++++++++------
M
src/planeto/htrdr_planeto_c.h
 | 
1
+
M
src/planeto/htrdr_planeto_draw_map.c
 | 
18
+++++++++++++++++-

3 files changed, 65 insertions(+), 7 deletions(-)
diff --git a/src/planeto/htrdr_planeto.c b/src/planeto/htrdr_planeto.c
@@ -19,6 +19,7 @@
 
 #include "core/htrdr.h"
 #include "core/htrdr_ran_wlen_cie_xyz.h"
+#include "core/htrdr_ran_wlen_discrete.h"
 #include "core/htrdr_ran_wlen_planck.h"
 #include "core/htrdr_log.h"
 
@@ -232,6 +233,49 @@ error:
   goto exit;
 }
 
+static res_T
+setup_spectral_domain_sw
+  (struct htrdr_planeto* cmd,
+   const struct htrdr_planeto_args* args)
+{
+  res_T res = RES_OK;
+  ASSERT(cmd && args);
+  ASSERT(cmd->spectral_domain.type == HTRDR_SPECTRAL_SW);
+
+  /* Discrete distribution */
+  if(args->source.rnrl_filename) {
+    struct htrdr_planeto_source_spectrum spectrum;
+    struct htrdr_ran_wlen_discrete_create_args discrete_args;
+
+    res = htrdr_planeto_source_get_spectrum
+      (cmd->source, cmd->spectral_domain.wlen_range, &spectrum);
+    if(res != RES_OK) goto error;
+
+    discrete_args.get = htrdr_planeto_source_spectrum_at;
+    discrete_args.nwavelengths = spectrum.size;
+    discrete_args.context = &spectrum;
+    res = htrdr_ran_wlen_discrete_create
+      (cmd->htrdr, &discrete_args, &cmd->discrete);
+    if(res != RES_OK) goto error;
+
+  /* Planck distribution */
+  } else {
+    const size_t nintervals = compute_nintervals_for_spectral_cdf(cmd);
+
+    /* Use the source temperature as the reference temperature of the Planck
+     * distribution */
+    res = htrdr_ran_wlen_planck_create(cmd->htrdr,
+      cmd->spectral_domain.wlen_range, nintervals, args->source.temperature,
+      &cmd->planck);
+    if(res != RES_OK) goto error;
+  }
+
+exit:
+  return res;
+error:
+  goto exit;
+}
+
 static INLINE res_T
 setup_spectral_domain
   (struct htrdr_planeto* cmd,
@@ -245,7 +289,6 @@ setup_spectral_domain
   cmd->spectral_domain = args->spectral_domain;
 
   /* Configure the spectral distribution */
-  nintervals = compute_nintervals_for_spectral_cdf(cmd);
   switch(cmd->spectral_domain.type) {
 
     case HTRDR_SPECTRAL_LW:
@@ -255,6 +298,7 @@ setup_spectral_domain
       /* Use as the reference temperature of the Planck distribution the
        * maximum scene temperature which, in fact, should be the maximum ground
        * temperature */
+      nintervals = compute_nintervals_for_spectral_cdf(cmd);
       res = htrdr_ran_wlen_planck_create(cmd->htrdr,
         cmd->spectral_domain.wlen_range, nintervals, ground_T_range[1],
         &cmd->planck);
@@ -262,16 +306,13 @@ setup_spectral_domain
       break;
 
     case HTRDR_SPECTRAL_SW:
-      /* Use the source temperature as the reference temperature of the Planck
-       * distribution */
-      res = htrdr_ran_wlen_planck_create(cmd->htrdr,
-        cmd->spectral_domain.wlen_range, nintervals, args->source.temperature,
-        &cmd->planck);
+      res = setup_spectral_domain_sw(cmd, args);
       if(res != RES_OK) goto error;
       break;
 
     case HTRDR_SPECTRAL_SW_CIE_XYZ:
       /* CIE XYZ distribution */
+      nintervals = compute_nintervals_for_spectral_cdf(cmd);
       res = htrdr_ran_wlen_cie_xyz_create(cmd->htrdr,
         cmd->spectral_domain.wlen_range, nintervals, &cmd->cie);
       if(res != RES_OK) goto error;
diff --git a/src/planeto/htrdr_planeto_c.h b/src/planeto/htrdr_planeto_c.h
@@ -85,6 +85,7 @@ struct htrdr_planeto {
   struct htrdr_planeto_spectral_args spectral_domain;
   struct htrdr_ran_wlen_cie_xyz* cie; /* HTRDR_SPECTRAL_SW_CIE_XYZ */
   struct htrdr_ran_wlen_planck* planck; /* HTRDR_SPECTRAL_<LW|SW> */
+  struct htrdr_ran_wlen_discrete* discrete; /* HTRDR_SPECTRAL_SW */
 
   FILE* octrees_storage;
 
diff --git a/src/planeto/htrdr_planeto_draw_map.c b/src/planeto/htrdr_planeto_draw_map.c
@@ -16,6 +16,7 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>. */
 
 #include "planeto/htrdr_planeto_c.h"
+#include "planeto/htrdr_planeto_source.h"
 
 #include "core/htrdr.h"
 #include "core/htrdr_accum.h"
@@ -23,6 +24,7 @@
 #include "core/htrdr_draw_map.h"
 #include "core/htrdr_log.h"
 #include "core/htrdr_ran_wlen_cie_xyz.h"
+#include "core/htrdr_ran_wlen_discrete.h"
 #include "core/htrdr_ran_wlen_planck.h"
 
 #include <rad-net/rnatm.h>
@@ -92,7 +94,21 @@ draw_pixel_xwave
     r2 = ssp_rng_canonical(args->rng);
 
     /* Sample a wavelength */
-    wlen[0] = wlen[1] = htrdr_ran_wlen_planck_sample(cmd->planck, r0, r1, &pdf);
+    switch(cmd->spectral_domain.type) {
+      case HTRDR_SPECTRAL_LW:
+        wlen[0] = htrdr_ran_wlen_planck_sample(cmd->planck, r0, r1, &pdf);
+        break;
+      case HTRDR_SPECTRAL_SW:
+        if(htrdr_planeto_source_does_radiance_vary_spectrally(cmd->source)) {
+          wlen[0] = htrdr_ran_wlen_discrete_sample(cmd->discrete, r0, r1, &pdf);
+        } else {
+          wlen[0] = htrdr_ran_wlen_planck_sample(cmd->planck, r0, r1, &pdf);
+        }
+        break;
+      default: FATAL("Unreachable code\n"); break;
+
+    }
+    wlen[1] = wlen[0];
     pdf *= 1.e9; /* Transform the pdf from nm⁻¹ to m⁻¹ */
 
     /* Find the band the wavelength belongs to and sample a quadrature point */