Fix T89330 Exact Boolean fails on a simple model.

The problem was an optimization I put in to triangulate quads.
It was wrong if the quad, after projecting onto a 2d plane, was
not convex. Handling quads the same as other faces fixes the bug.
Unfortunately, this will slow down Exact Boolean when the input has
many quads (the usual case, of course).
Will attempt to fix that with a later change, but for now, this
at least restores correctness.

1 files changed, 70 insertions, 0 deletions

diff --git a/source/blender/blenlib/tests/BLI_mesh_intersect_test.cc b/source/blender/blenlib/tests/BLI_mesh_intersect_test.cc
index ec57cf29cad..1a9ffbd3403 100644
--- a/source/blender/blenlib/tests/BLI_mesh_intersect_test.cc
+++ b/source/blender/blenlib/tests/BLI_mesh_intersect_test.cc
@@ -174,6 +174,76 @@ TEST(mesh_intersect, Mesh)
   EXPECT_TRUE(f->is_tri());
 }
 
+TEST(mesh_intersect, TriangulateTri)
+{
+  const char *spec = R"(3 1
+  0 0 0
+  1 0 0
+  1/2 1 0
+  0 1 2
+  )";
+
+  IMeshBuilder mb(spec);
+  IMesh im_tri = triangulate_polymesh(mb.imesh, &mb.arena);
+  EXPECT_EQ(im_tri.faces().size(), 1);
+}
+
+TEST(mesh_intersect, TriangulateQuad)
+{
+  const char *spec = R"(4 1
+  0 0 0
+  1 0 0
+  1 1 0
+  0 1 0
+  0 1 2 3
+  )";
+
+  IMeshBuilder mb(spec);
+  IMesh im_tri = triangulate_polymesh(mb.imesh, &mb.arena);
+  EXPECT_EQ(im_tri.faces().size(), 2);
+}
+
+TEST(mesh_intersect, TriangulatePentagon)
+{
+  const char *spec = R"(5 1
+  0 0 0
+  1 0 0
+  1 1 0
+  1/2 2 0
+  0 1 0
+  0 1 2 3 4
+  )";
+
+  IMeshBuilder mb(spec);
+  IMesh im_tri = triangulate_polymesh(mb.imesh, &mb.arena);
+  EXPECT_EQ(im_tri.faces().size(), 3);
+  if (DO_OBJ) {
+    write_obj_mesh(im_tri, "pentagon");
+  }
+}
+
+TEST(mesh_intersect, TriangulateTwoFaces)
+{
+  const char *spec = R"(7 2
+  461/250 -343/125 103/1000
+  -3/40 -453/200 -97/500
+  237/100 -321/200 -727/500
+  451/1000 -563/500 -1751/1000
+  12/125 -2297/1000 -181/1000
+  12/125 -411/200 -493/1000
+  1959/1000 -2297/1000 -493/1000
+  1 3 2 0 6 5 4
+  6 0 1 4
+  )";
+
+  IMeshBuilder mb(spec);
+  IMesh im_tri = triangulate_polymesh(mb.imesh, &mb.arena);
+  EXPECT_EQ(im_tri.faces().size(), 7);
+  if (DO_OBJ) {
+    write_obj_mesh(im_tri, "twofaces");
+  }
+}
+
 TEST(mesh_intersect, OneTri)
 {
   const char *spec = R"(3 1