From e12e1f7f19badd0080766e44163fe48c14436c79 Mon Sep 17 00:00:00 2001
From: Chris Mackey <chris@ladybug.tools>
Date: Thu, 2 Sep 2021 16:44:27 -0400
Subject: [PATCH] fix(face): Avoid removing the last vertex twice

It seems that the remove_colinear_vertices method would remove the last vertex twice if those last two vertices were equivalent to one another. This is not necessarily what you want unless both of those last two vertices are colinear with the vertices surrounding it. This commit fixes this case.
---
 ladybug_geometry/geometry3d/face.py |  5 +++++
 tests/face3d_test.py                | 12 ++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/ladybug_geometry/geometry3d/face.py b/ladybug_geometry/geometry3d/face.py
index daa3663c..31ce01e4 100644
--- a/ladybug_geometry/geometry3d/face.py
+++ b/ladybug_geometry/geometry3d/face.py
@@ -1747,6 +1747,11 @@ def _remove_colinear(self, pts_3d, pts_2d, tolerance):
                 skip = 0
             else:
                 skip += 1
+        if skip != 0 and pts_3d[-2].is_equivalent(pts_3d[-1], tolerance):
+            _a = pts_2d[-3].determinant(pts_2d[-1]) + \
+                pts_2d[-1].determinant(pts_2d[0]) + pts_2d[0].determinant(pts_2d[-3])
+            if abs(_a) >= tolerance:
+                new_vertices.append(pts_3d[-1])
         return new_vertices
 
     def _is_sub_face(self, face):
diff --git a/tests/face3d_test.py b/tests/face3d_test.py
index bd7fad43..36ad7472 100644
--- a/tests/face3d_test.py
+++ b/tests/face3d_test.py
@@ -594,12 +594,24 @@ def test_remove_colinear_vertices():
     pts_1 = (Point3D(0, 0), Point3D(2, 0), Point3D(2, 2), Point3D(0, 2))
     pts_2 = (Point3D(0, 0), Point3D(1, 0), Point3D(2, 0), Point3D(2, 2),
              Point3D(0, 2))
+    pts_3 = (Point3D(0, 0), Point3D(2, 0), Point3D(2, 2),
+             Point3D(0, 2), Point3D(0, 2))
+    pts_4 = (Point3D (24.21, 23.22, 8.00), Point3D (24.21, 23.22, 11.60),
+             Point3D (24.61, 23.22, 11.60), Point3D (27.85, 23.22, 11.60),
+             Point3D (30.28, 23.22, 11.60), Point3D (30.28, 23.22, 0.00),
+             Point3D (27.85, 23.22, 0.00), Point3D (27.85, 23.22, 4.00),
+             Point3D (27.85, 23.22, 8.00), Point3D (27.85, 23.22, 8.00),
+             Point3D (24.61, 23.22, 8.00), Point3D (24.61, 23.22, 8.00))
     plane_1 = Plane(Vector3D(0, 0, 1))
     face_1 = Face3D(pts_1, plane_1)
     face_2 = Face3D(pts_2, plane_1)
+    face_3 = Face3D(pts_3, plane_1)
+    face_4 = Face3D(pts_4)
 
     assert len(face_1.remove_colinear_vertices(0.0001).vertices) == 4
     assert len(face_2.remove_colinear_vertices(0.0001).vertices) == 4
+    assert len(face_3.remove_colinear_vertices(0.0001).vertices) == 4
+    assert len(face_4.remove_colinear_vertices(0.0001).vertices) == 6
 
 
 def test_remove_colinear_vertices_custom():