star-enclosures-3d

commit 906ed56bcfc2e8c105602b7b73dd6d9b3f68c57f
parent 051843e1a9032660bf2a7ff35030e39bbaa9d5c3
Author: Christophe Coustet <christophe.coustet@meso-star.com>
Date:   Wed,  6 May 2020 07:29:32 +0200

Fix misleading comments and small changes to the code

The modified code, that is supposed to give the same results, is
clearer.

Diffstat:
M
src/senc3d_scene_analyze.c
 | 
43
+++++++++++++++++++++++++------------------

1 file changed, 25 insertions(+), 18 deletions(-)
diff --git a/src/senc3d_scene_analyze.c b/src/senc3d_scene_analyze.c
@@ -163,7 +163,7 @@ self_hit_filter
     ((s < 0) /* Facing geometrical normal of hit */
       == ((filter_ctx->scn->convention & SENC3D_CONVENTION_NORMAL_FRONT) != 0))
     /* Warning: following Embree 2 convention for geometrical normals,
-     * the Star3D hit normal is left-handed while star-enclosure uses
+     * the Star3D hit normal is left-handed while star-enclosures-3d uses
      * right-handed convention */
     ? SENC3D_BACK : SENC3D_FRONT;
   filter_ctx->hit_component = hit_trg_comp->component[hit_side];
@@ -248,9 +248,9 @@ extract_connex_components
     /* Any not-already-used side is used as a starting point */
     side_id_t first_side_not_in_component = media_use->first;
     double max_nz;
-    side_id_t max_nz_side_id = SIDE_NULL__;
+    side_id_t max_nz_side_id;
     const side_id_t last_side = media_use->last;
-    int component_canceled = 0;
+    int component_canceled = 0, max_z_is_2sided = 0;
     res_T tmp_res = RES_OK;
     ATOMIC id;
 
@@ -444,8 +444,12 @@ extract_connex_components
         cmp[sid] = cc->cc_id;
       }
 
-      /* Compute the normal at the max_z vertex. */
+      /* Determine if this component can be an inner part inside another
+       * component (creating a hole) as only these components will need
+       * to search for their possible outer component when grouping
+       * components to create encosures */
       max_nz = 0;
+      max_nz_side_id = SIDE_NULL__;
       sz = darray_side_id_size_get(&ids_of_sides_around_max_z_vertex);
       ASSERT(sz > 0);
       FOR_EACH(ii, 0, sz) {
@@ -460,13 +464,7 @@ extract_connex_components
           darray_position_cdata_get(&scn->vertices);
         double edge0[3], edge1[3], normal[3], norm;
 
-        /* To ensure that triangles with 2 sides in the component total to 0
-         * regardless of numeric accuracy, we need to prevent them to
-         * contribute (remember than x + y - y == x can be false). */
         ASSERT(trg_comp->component[s] == cc->cc_id); (void)s;
-        if(trg_comp->component[SENC3D_FRONT] == trg_comp->component[SENC3D_BACK])
-          continue;
-
         d3_sub(edge0, vertices[trg_in->vertice_id[1]].vec,
           vertices[trg_in->vertice_id[0]].vec);
         d3_sub(edge1, vertices[trg_in->vertice_id[2]].vec,
@@ -478,10 +476,18 @@ extract_connex_components
         if(fabs(max_nz) < fabs(normal[2])) {
           max_nz_side_id = side_id;
           max_nz = normal[2];
+          max_z_is_2sided = (trg_comp->component[SENC3D_FRONT]
+            == trg_comp->component[SENC3D_BACK]);
         }
       }
-      if(max_nz == 0) cc->is_outer_border = 0;
+      /* The inner/outer property comes from the normal orientation of the
+       * triangle on top of the component, this triangle being the one whose
+       * |Nz| is maximal. If this triangle has its 2 sides in the component,
+       * the component is inner */
+      if(max_nz == 0) ASSERT(max_z_is_2sided);
+      if(max_z_is_2sided) cc->is_outer_border = 0;
       else {
+        ASSERT(max_nz_side_id != SIDE_NULL__);
         if(TRGSIDE_IS_FRONT(max_nz_side_id)
           == ((scn->convention & SENC3D_CONVENTION_NORMAL_FRONT) != 0)) {
           /* Geom normal points towards the component */
@@ -634,7 +640,7 @@ group_connex_components
     max_vrtx = positions[cc->max_z_vrtx_id].vec;
     if(cc->is_outer_border) {
       ATOMIC id;
-      /* Don't need to cast a ray */
+      /* No need to query closest point */
       cc->cc_group_root = cc->cc_id; /* New group with self as root */
       id = ATOMIC_INCR(next_enclosure_id) - 1;
       ASSERT(id <= ENCLOSURE_MAX__);
@@ -1012,6 +1018,7 @@ build_result
   const struct triangle_comp* triangles_comp;
   struct htable_vrtx_id vtable;
   int output_normal_in, normals_front, normals_back;
+  size_t cc_count;
   int64_t tt;
   int64_t ee;
 
@@ -1024,8 +1031,8 @@ build_result
   ASSERT(normals_back != normals_front);
   ASSERT(output_normal_in
     != ((scn->convention & SENC3D_CONVENTION_NORMAL_OUTSIDE) != 0));
-  ASSERT(darray_ptr_component_descriptor_size_get(connex_components)
-    <= COMPONENT_MAX__);
+  cc_count = darray_ptr_component_descriptor_size_get(connex_components);
+  ASSERT(cc_count <= COMPONENT_MAX__);
   cc_descriptors = darray_ptr_component_descriptor_cdata_get(connex_components);
   enclosures = darray_enclosure_data_get(&scn->analyze.enclosures);
   triangles_in = darray_triangle_in_cdata_get(&scn->triangles_in);
@@ -1054,9 +1061,10 @@ build_result
       ordered_ids[rank] = e;
     }
     /* Rewrite cc_descriptors */
-    FOR_EACH(d, 0, darray_ptr_component_descriptor_size_get(connex_components))
+    FOR_EACH(d, 0, cc_count) {
       cc_descriptors[d]->enclosure_id =
-      ordered_ids[cc_descriptors[d]->enclosure_id];
+        ordered_ids[cc_descriptors[d]->enclosure_id];
+    }
   single_err: (void)0;
   }/* Implicit barrier here. */
   if(*res != RES_OK) goto exit;
@@ -1093,8 +1101,7 @@ build_result
     trg_id_t t;
     medium_id_t m;
     res_T tmp_res = RES_OK;
-    ASSERT(enc->first_component
-      < darray_ptr_component_descriptor_size_get(connex_components));
+    ASSERT(enc->first_component < cc_count);
     ASSERT(cc_descriptors[enc->first_component]->cc_id
       == enc->first_component);