Fix crash in delaunay C interface test.

The test forgot to set the new need_ids field, which luckily
exposed a bug in the C api for delaunay when that field is false.
Fixed the bug and the test, and added a test for the need_ids false
case.

2 files changed, 29 insertions, 2 deletions

diff --git a/source/blender/blenlib/intern/delaunay_2d.cc b/source/blender/blenlib/intern/delaunay_2d.cc
index 362dbdf15c5..08f18d5cbf3 100644
--- a/source/blender/blenlib/intern/delaunay_2d.cc
+++ b/source/blender/blenlib/intern/delaunay_2d.cc
@@ -2851,10 +2851,12 @@ extern "C" ::CDT_result *BLI_delaunay_2d_cdt_calc(const ::CDT_input *input,
     for (int e = 0; e < ne; ++e) {
       tot_e_orig += res.edge_orig[e].size();
     }
-    for (int f = 0; f < nf; ++f) {
+  }
+  for (int f = 0; f < nf; ++f) {
+    if (input->need_ids) {
       tot_f_orig += res.face_orig[f].size();
-      tot_f_lens += res.face[f].size();
     }
+    tot_f_lens += res.face[f].size();
   }
 
   output->vert_coords = static_cast<decltype(output->vert_coords)>(
diff --git a/source/blender/blenlib/tests/BLI_delaunay_2d_test.cc b/source/blender/blenlib/tests/BLI_delaunay_2d_test.cc
index bc6b7e9fe4e..cd2d48eac4d 100644
--- a/source/blender/blenlib/tests/BLI_delaunay_2d_test.cc
+++ b/source/blender/blenlib/tests/BLI_delaunay_2d_test.cc
@@ -1756,9 +1756,34 @@ TEST(delaunay_d, CintTwoFace)
   input.faces_len_table = faces_len;
   input.faces_start_table = faces_start;
   input.epsilon = 1e-5f;
+  input.need_ids = false;
   ::CDT_result *output = BLI_delaunay_2d_cdt_calc(&input, CDT_FULL);
   BLI_delaunay_2d_cdt_free(output);
 }
+
+TEST(delaunay_d, CintTwoFaceNoIds)
+{
+  float vert_coords[][2] = {
+      {0.0, 0.0}, {1.0, 0.0}, {0.5, 1.0}, {1.1, 1.0}, {1.1, 0.0}, {1.6, 1.0}};
+  int faces[] = {0, 1, 2, 3, 4, 5};
+  int faces_len[] = {3, 3};
+  int faces_start[] = {0, 3};
+
+  ::CDT_input input;
+  input.verts_len = 6;
+  input.edges_len = 0;
+  input.faces_len = 2;
+  input.vert_coords = vert_coords;
+  input.edges = nullptr;
+  input.faces = faces;
+  input.faces_len_table = faces_len;
+  input.faces_start_table = faces_start;
+  input.epsilon = 1e-5f;
+  input.need_ids = true;
+  ::CDT_result *output = BLI_delaunay_2d_cdt_calc(&input, CDT_FULL);
+  BLI_delaunay_2d_cdt_free(output);
+}
+
 #endif
 
 #if DO_TEXT_TESTS