htrdr

commit c5b3eb65d9d62b4f2b4da0ca75e7c06958b466b9
parent 9e449d549dc533e3b3c98750aa63be174fbc39c7
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Thu, 22 Apr 2021 11:53:11 +0200

Add the htrdr_geometry_get_epsilon function

Return a pre-computed empirical value relative to the extent of the
geometry that represents the threshold below which a numerical problem
could occur.

Diffstat:
M
src/core/htrdr_geometry.c
 | 
19
+++++++++++++++++++
M
src/core/htrdr_geometry.h
 | 
6
++++++

2 files changed, 25 insertions(+), 0 deletions(-)
diff --git a/src/core/htrdr_geometry.c b/src/core/htrdr_geometry.c
@@ -75,6 +75,10 @@ struct htrdr_geometry {
   float upper[3]; /* Ground upper bound */
   int repeat; /* Make the geom infinite in X and Y */
 
+  /* A empirical value relative to the extent of the geometry that represents
+   * the threshold below which a numerical problem could occur. */
+  float epsilon;
+
   struct htable_interface interfaces; /* Map a Star3D shape to its interface */
 
   struct htrdr* htrdr;
@@ -581,6 +585,10 @@ htrdr_geometry_create
 {
   char buf[128];
   struct htrdr_geometry* geom = NULL;
+  double low[3];
+  double upp[3];
+  double tmp[3];
+  double extent;
   struct time t0, t1;
   res_T res = RES_OK;
   ASSERT(htrdr && obj_filename && mats && out_ground);
@@ -608,6 +616,10 @@ htrdr_geometry_create
   time_dump(&t0, TIME_ALL, NULL, buf, sizeof(buf));
   htrdr_log(geom->htrdr, "Setup geom in %s\n", buf);
 
+  htrdr_geometry_get_aabb(geom, low, upp);
+  extent = d3_len(d3_sub(tmp, upp, low));
+  geom->epsilon = MMAX((float)(extent * 1e-6), FLT_EPSILON);
+
 exit:
   *out_ground = geom;
   return res;
@@ -738,3 +750,10 @@ htrdr_geometry_get_aabb
   d3_set_f3(lower, geom->lower);
   d3_set_f3(upper, geom->upper);
 }
+
+double
+htrdr_geometry_get_epsilon(const struct htrdr_geometry* geom)
+{
+  ASSERT(geom);
+  return geom->epsilon;
+}
diff --git a/src/core/htrdr_geometry.h b/src/core/htrdr_geometry.h
@@ -98,6 +98,12 @@ htrdr_geometry_get_aabb
    double lower[3],
    double upper[3]);
 
+/* Empirical value relative to the extent of the geometry that represents the
+ * threshold below which a numerical problem could occur. */
+HTRDR_CORE_API double
+htrdr_geometry_get_epsilon
+  (const struct htrdr_geometry* geom);
+
 END_DECLS
 
 #endif /* HTRDR_GEOMETRY_H */