Change where z-sorting happens in 3d camera

camera/three_d_camera.py

@@ -6,6 +6,7 @@ from constants import *
 
 from camera.camera import Camera
 from mobject.types.point_cloud_mobject import Point
+from mobject.types.vectorized_mobject import VMobject
 from mobject.three_d_utils import get_3d_vmob_start_corner
 from mobject.three_d_utils import get_3d_vmob_start_corner_unit_normal
 from mobject.three_d_utils import get_3d_vmob_end_corner
@@ -94,22 +95,27 @@ class ThreeDCamera(Camera):
             vmobject, vmobject.get_fill_rgbas()
         )
 
-    def display_multiple_vectorized_mobjects(self, vmobjects, pixel_array):
+    def get_mobjects_to_display(self, *args, **kwargs):
+        mobjects = Camera.get_mobjects_to_display(
+            self, *args, **kwargs
+        )
         rot_matrix = self.get_rotation_matrix()
 
-        def z_key(vmob):
+        def z_key(mob):
+            if not isinstance(mob, VMobject):
+                return np.inf
+            if not mob.shade_in_3d:
+                return np.inf
             # Assign a number to a three dimensional mobjects
             # based on how close it is to the camera
-            if vmob.shade_in_3d:
+            points = mob.points
+            if len(points) == 0:
+                return 0
             return np.dot(
-                    vmob.get_center(),
+                center_of_mass(points),
                 rot_matrix.T
             )[2]
-            else:
-                return np.inf
-        Camera.display_multiple_vectorized_mobjects(
-            self, sorted(vmobjects, key=z_key), pixel_array
-        )
+        return sorted(mobjects, key=z_key)
 
     def get_phi(self):
         return self.phi_tracker.get_value()