star-phor-input

commit 4d57423397b6ac7aa0a6cd184ca160d9c180ef88
parent 7d41b6c42c46e3bd1a4bd59ee66cf841501b0679
Author: Eduardo Fontana Lazzari <edufonlaz@gmail.com>
Date:   Mon, 24 Mar 2025 13:46:49 +0100

Allow unit specification for geometries in the input file

Geometries are now scaled according to the specified unit.
Added corresponding tests and documentation.

Diffstat:
M
doc/star-phor-input.scd
 | 
3
++-
M
src/sphin_geometry.c
 | 
13
++++++++++++-
M
src/test_sphin_load_geometry.c
 | 
40
++++++++++++++++++++++++++++++++++++----

3 files changed, 50 insertions(+), 6 deletions(-)
diff --git a/doc/star-phor-input.scd b/doc/star-phor-input.scd
@@ -56,9 +56,10 @@ The file format describing a photoreactive system is as follows:++
                                        [<sensor>]++
                                        [<surface-source>]++
 ++
-<geometry>               ::=   *geometry:* <geometry-side> <geometry-filename>++
+<geometry>               ::=   *geometry:* <geometry-side> <geometry-filename> [<geometry-unit>]++
 <geometry-side>          ::=   *FRONT* | *BACK*++
 <geometry-filename>      ::=   path  % STL files only; spaces not allowed ++
+<geometry-unit>          ::=   *m* | *cm* | *mm* | *km* % if no unit is specified, meter is assumed++
 ++
 <sensor>                 ::=   *sensor:* [<comment>]++
                                        *response_function:* real++
diff --git a/src/sphin_geometry.c b/src/sphin_geometry.c
@@ -104,10 +104,12 @@ geometry_parse
   char* side = NULL;
   char* filename = NULL;
   char* token_ptr = NULL;
+  char* unit = NULL;
   struct sphin_geometry* geom = NULL;
   struct sstl* sstl = NULL;
   struct sstl_desc sstl_desc;
   double* coords = NULL;
+  double scaling_factor;
   size_t* indices = NULL;
   res_T res = RES_OK;
 
@@ -133,6 +135,15 @@ geometry_parse
   filename = strtok_r(NULL, " \t", &token_ptr);
   if (NULL == filename){ res = RES_BAD_ARG; goto error; }
 
+  /* Parse unit and evaluate scaling factor*/
+  unit = strtok_r(NULL, " \t", &token_ptr);
+  if (NULL == unit
+        || 0 == strcmp(unit, "m")){scaling_factor = 1e+00;}
+  else if (0 == strcmp(unit, "cm")){scaling_factor = 1e-02;}
+  else if (0 == strcmp(unit, "mm")){scaling_factor = 1e-03;}
+  else if (0 == strcmp(unit, "km")){scaling_factor = 1e+03;}
+  else { res = RES_BAD_ARG; goto error; }
+
   /* Create geometry */
   res = geometry_create(sphin, filename, &geom);
   if (RES_OK != res) { goto error; }
@@ -154,7 +165,7 @@ geometry_parse
   indices = darray_size_t_data_get(&geom->indices);
 
   FOR_EACH(i, 0, sstl_desc.vertices_count*3) {
-    coords[i] = (double)sstl_desc.vertices[i];
+    coords[i] = (double)sstl_desc.vertices[i]*scaling_factor;
   }
   FOR_EACH(i, 0, sstl_desc.triangles_count*3) {
     indices[i] = (size_t)sstl_desc.indices[i];
diff --git a/src/test_sphin_load_geometry.c b/src/test_sphin_load_geometry.c
@@ -25,6 +25,7 @@
 #include "sphin.h"
 #include "test_sphin_utils.h"
 
+#include <rsys/math.h>
 #include <rsys/mem_allocator.h>
 #include <string.h>
 
@@ -48,8 +49,8 @@ write_stl_test_files
     "  facet normal 0.0 0.0 -1.0\n"
     "    outer loop\n"
     "      vertex 0.0 0.0 0.0\n"
-    "      vertex 1.0 0.0 0.0\n"
-    "      vertex 0.0 1.0 0.0\n"
+    "      vertex 1.935 0.0 0.0\n"
+    "      vertex 0.0 0.0 3.142\n"
     "    endloop\n"
     "  endfacet\n"
     "endsolid";
@@ -168,8 +169,11 @@ test_geometry_api
   CHK(fp = fopen(path, "w+"));
   fprintf(fp, "\t\t surface : \"surface name\"\n");
   fprintf(fp, "\tgeometry: FRONT test_0.stl\t\n");
-  fprintf(fp, "\tgeometry: BACK test_1.stl \t\n");
+  fprintf(fp, "\tgeometry: BACK test_1.stl\t\n");
   fprintf(fp, "\tgeometry: BACK test_2.stl\n");
+  fprintf(fp, "\tgeometry: BACK test_1.stl cm\t\n");
+  fprintf(fp, "\tgeometry: BACK test_1.stl mm\t\n");
+  fprintf(fp, "\tgeometry: BACK test_1.stl km\t\n");
   fclose(fp);
 
   CHK(sphin_load(sphin, path, &config) == RES_OK);
@@ -178,7 +182,7 @@ test_geometry_api
   CHK(sphin_config_get_surface(config, 0, &surface) == RES_OK);
   CHK(sphin_surface_get_geometry_count(NULL, &ngeometries) == RES_BAD_ARG);
   CHK(sphin_surface_get_geometry_count(surface, &ngeometries) == RES_OK);
-  CHK(ngeometries == 3);
+  CHK(ngeometries == 6);
 
   igeometry = 0;
   CHK(sphin_surface_get_geometry(surface, igeometry, &geom) == RES_OK);
@@ -204,6 +208,34 @@ test_geometry_api
   CHK(desc.mesh.vertex_count == 8);
   CHK(strcmp(desc.filename, "test_2.stl") == 0);
 
+  /* Test geometry units */
+
+  /* In the following assertions, we use an epsilon (tolerable error) of 1e-6
+   * instead of the 1e-15 used elsewhere in sphin. This is because, although
+   * sphin performs all computations using doubles, the third-party library
+   * star-stl, which is used to parse STL files, handles mesh coordinates
+   * using floats (even though those are exposed as doubles by sphin).
+   * As a result, the precision of geometrical coordinates is
+   * limited to approximately six digits. */
+
+  igeometry++;
+  CHK(sphin_surface_get_geometry(surface, igeometry, &geom) == RES_OK);
+  CHK(sphin_geometry_get_desc(geom, &desc) == RES_OK);
+  CHK(eq_eps(desc.mesh.coords[3], 0.01935, 1e-9));
+  CHK(eq_eps(desc.mesh.coords[8], 0.03142, 1e-9));
+
+  igeometry++;
+  CHK(sphin_surface_get_geometry(surface, igeometry, &geom) == RES_OK);
+  CHK(sphin_geometry_get_desc(geom, &desc) == RES_OK);
+  CHK(eq_eps(desc.mesh.coords[3], 0.001935, 1e-8));
+  CHK(eq_eps(desc.mesh.coords[8], 0.003142, 1e-8));
+
+  igeometry++;
+  CHK(sphin_surface_get_geometry(surface, igeometry, &geom) == RES_OK);
+  CHK(sphin_geometry_get_desc(geom, &desc) == RES_OK);
+  CHK(eq_eps(desc.mesh.coords[3], 1935, 1e-3));
+  CHK(eq_eps(desc.mesh.coords[8], 3142, 1e-3));
+
   CHK(sphin_geometry_ref_get(NULL) == RES_BAD_ARG);
   CHK(sphin_geometry_ref_put(NULL) == RES_BAD_ARG);
   CHK(sphin_geometry_ref_get(geom) == RES_OK);