star-geometry-3d

commit 5a6be30faf321766ced4d2e12a89d979b707b324
parent dd7e9ca85edbec1087cb81e8f609b5f4d12e5211
Author: Christophe Coustet <christophe.coustet@meso-star.com>
Date:   Wed, 10 Jun 2020 15:47:08 +0200

BugFix: some degenerated triangles where not detected

Diffstat:
M
src/sg3d_geometry.c
 | 
19
++++++++++++++-----
M
src/test_sg3d_geometry.c
 | 
26
++++++++++++++++++++++----

2 files changed, 36 insertions(+), 9 deletions(-)
diff --git a/src/sg3d_geometry.c b/src/sg3d_geometry.c
@@ -432,7 +432,7 @@ sg3d_geometry_add
   /* Get triangles and deduplicate */
   trg = darray_triangle_data_get(&geom->unique_triangles);
   FOR_EACH(nt, 0, ntris) {
-    int j, reversed;
+    int j, reversed, dg;
     struct vrtx_id3 trg_key;
     struct triangle tmp = TRG_UNDEF__;
     trg_id_t* p_trg;
@@ -449,16 +449,25 @@ sg3d_geometry_add
       tmp.vertex_ids[j]
         = darray_vertice_ids_cdata_get(&unique_vertice_ids)[tmp.vertex_ids[j]];
     }
-    if(tmp.vertex_ids[0] == tmp.vertex_ids[1]
+    dg = (tmp.vertex_ids[0] == tmp.vertex_ids[1]
       || tmp.vertex_ids[0] == tmp.vertex_ids[2]
-      || tmp.vertex_ids[1] == tmp.vertex_ids[2])
-    {
+      || tmp.vertex_ids[1] == tmp.vertex_ids[2]);
+    if(!dg) {
+      double edge1[3], edge2[3], n[3];
+      const struct vertex* vertices = darray_vertex_cdata_get(&geom->unique_vertices);
+      d3_sub(edge1, vertices[tmp.vertex_ids[1]].coord, vertices[tmp.vertex_ids[0]].coord);
+      d3_sub(edge2, vertices[tmp.vertex_ids[2]].coord, vertices[tmp.vertex_ids[0]].coord);
+      d3_cross(n, edge1, edge2);
+      dg = d3_len(n) == 0;
+    }
+    if(dg) {
       int abort = 0;
       if(dege_trg) {
         /* Let the client app rule. */
         ERR(dege_trg(nt, ctx, &abort));
       } else {
-        log_warn(geom->dev, "%s: triangle "PRTF_TRG" is degenerated.\n",
+        log_warn(geom->dev,
+          "%s: triangle "PRTF_TRG" is degenerated (removed).\n",
           FUNC_NAME, nt);
       }
       if(abort) {
diff --git a/src/test_sg3d_geometry.c b/src/test_sg3d_geometry.c
@@ -68,7 +68,10 @@ main(int argc, char** argv)
   struct sg3d_geometry* geom;
   double coord[3];
   unsigned indices[3];
-  const unsigned degenerated[3] = { 0 , 0, 0 };
+  const unsigned degenerated1[3] = { 0, 0, 0 };
+  const unsigned degenerated2[3] = { 0, 1, 2 };
+  const double degenerated_vertices[3/*#vertices*/ * 3/*#coords per vertex*/]
+    =  { 0.0, 0.0, 0.0,  1.0, 0.0, 0.0,  2.0, 0.0, 0.0 };
   unsigned properties[SG3D_PROP_TYPES_COUNT__];
   struct sg3d_geometry_add_callbacks callbacks = SG3D_ADD_CALLBACKS_NULL__;
   unsigned user_id;
@@ -270,8 +273,8 @@ main(int argc, char** argv)
   /* BA because of conflicts */
   BA(sg3d_geometry_dump_as_c_code(geom, stdout, "test", SG3D_C_DUMP_CONST));
 
-  /* Degenerated triangles */
-  ctx.indices = degenerated;
+  /* Degenerated triangles: duplicated vertex */
+  ctx.indices = degenerated1;
   /* Without callback : OK */
   OK(sg3d_geometry_add(geom, nvertices, 1, &callbacks, &ctx));
   /* With callback : OK */
@@ -280,7 +283,22 @@ main(int argc, char** argv)
   i = 0;
   OK(sg3d_geometry_add(geom, nvertices, 1, &callbacks, &ctx));
   /* With callback : KO */
-  i= 1;
+  i = 1;
+  BA(sg3d_geometry_add(geom, nvertices, 1, &callbacks, &ctx));
+
+  /* Degenerated triangles: flat triangle */
+  ctx.indices = degenerated2;
+  ctx.positions = degenerated_vertices;
+  callbacks.degenerated_triangle = NULL;
+  /* Without callback : OK */
+  OK(sg3d_geometry_add(geom, nvertices, 1, &callbacks, &ctx));
+  /* With callback : OK */
+  callbacks.degenerated_triangle = degenerated_triangle;
+  ctx.custom = &i;
+  i = 0;
+  OK(sg3d_geometry_add(geom, nvertices, 1, &callbacks, &ctx));
+  /* With callback : KO */
+  i = 1;
   BA(sg3d_geometry_add(geom, nvertices, 1, &callbacks, &ctx));
 
   OK(sg3d_geometry_ref_put(geom));