Accept edge case as Delaunay

Signed-off-by: pacien <pacien.trangirard@pacien.net>

2 files changed, 5 insertions, 4 deletions

diff --git a/src/morpher/quadrilateral.c b/src/morpher/quadrilateral.c
index 9c73dfa..d5c64b0 100644
--- a/src/morpher/quadrilateral.c
+++ b/src/morpher/quadrilateral.c
@@ -7,12 +7,12 @@ static inline IntVector p2(IntVector n) {
   return n * n;
 }
 
-static inline bool not_in_circumcircle(TriangleMap *t, CartesianVector v) {
+static inline bool in_circumcircle(TriangleMap *t, CartesianVector v) {
   CartesianVector a = t->vertices[0].origin, b = t->vertices[1].origin, c = t->vertices[2].origin;
   IntVector v2 = p2(v.x) + p2(v.y);
   return matrix_int_det3(a.x - v.x, a.y - v.y, p2(a.x) + p2(a.y) - v2,
                          b.x - v.x, b.y - v.y, p2(b.x) + p2(b.y) - v2,
-                         c.x - v.x, c.y - v.y, p2(c.x) + p2(c.y) - v2) > 0;
+                         c.x - v.x, c.y - v.y, p2(c.x) + p2(c.y) - v2) < 0;
 }
 
 static inline void rotate_vertices(TriangleMap *t1, TriangleMap *t2, int e1, int e2) {
@@ -58,6 +58,6 @@ void quadrilateral_flip_diagonal(TriangleMap *t1, TriangleMap *t2) {
 
 bool quadrilateral_is_delaunay(TriangleMap *t1, TriangleMap *t2) {
   assert(t1 != NULL && t2 != NULL);
-  return not_in_circumcircle(t1, t2->vertices[(trianglemap_find_common_edge(t2, t1) + 2) % 3].origin) &&
-         not_in_circumcircle(t2, t1->vertices[(trianglemap_find_common_edge(t1, t2) + 2) % 3].origin);
+  return !in_circumcircle(t1, t2->vertices[(trianglemap_find_common_edge(t2, t1) + 2) % 3].origin) &&
+         !in_circumcircle(t2, t1->vertices[(trianglemap_find_common_edge(t1, t2) + 2) % 3].origin);
 }
diff --git a/test/morpher/quadrilateral.c b/test/morpher/quadrilateral.c
index 31b22d6..c632b82 100644
--- a/test/morpher/quadrilateral.c
+++ b/test/morpher/quadrilateral.c
@@ -57,5 +57,6 @@ int main(int argc, char **argv) {
   test_quadrilateral_flip_diagonal();
   test_quadrilateral_is_delaunay(m(0, 0), m(0, 3), m(3, 3), m(2, 1), false);
   test_quadrilateral_is_delaunay(m(0, 0), m(0, 3), m(3, 3), m(4, -1), true);
+  test_quadrilateral_is_delaunay(m(0, 0), m(0, 1), m(1, 1), m(1, 0), true);
   return 0;
 }