Merge ed7e082c6f into 0e83f4b09a

manim/utils/space_ops.py

@@ -773,7 +773,11 @@ def earclip_triangulation(verts: np.ndarray, ring_ends: list) -> list:
         # Move the ring which j belongs to from the
         # attached list to the detached list
         new_ring = next(
-            (ring for ring in detached_rings if ring[0] <= j < ring[-1]), None
+            # ring[-1] is the last valid index in the ring so the upper bound needs
+            # to be inclusive. Otherwise, a connection point on a ring's final vertex
+            # doesn't match any ring and triggers "Could not find a ring to attach"
+            (ring for ring in detached_rings if ring[0] <= j <= ring[-1]),
+            None,
         )
         if new_ring is not None:
             detached_rings.remove(new_ring)

tests/module/utils/test_space_ops.py

@@ -122,3 +122,29 @@ def test_polar_coords():
     np.testing.assert_array_equal(
         np.round(spherical_to_cartesian(b), 4), np.array([0, 2, 0])
     )
+
+
+def test_triangulation_ring_connection():
+    verts = np.array(
+        [
+            # outer ring
+            [-2, -2, 0],
+            [2, -2, 0],
+            [2, 2, 0],
+            [-2, 2, 0],
+            # inner ring (hole)
+            [-0.5, -1.5, 0],
+            [-0.5, -0.5, 0],
+            [-1.5, -0.5, 0],
+            [-1.5, -1.5, 0],
+        ],
+        dtype=float,
+    )
+    ring_ends = [4, 8]
+
+    triangulation = earclip_triangulation(verts, ring_ends)
+
+    assert len(triangulation) > 0
+    assert len(triangulation) % 3 == 0
+    assert min(triangulation) >= 0
+    assert max(triangulation) < len(verts)