From 7a4fde180e64c7ba94b428c8b224550cb731cddd Mon Sep 17 00:00:00 2001
From: Anmol Singh <anmolzaildar4@gmail.com>
Date: Thu, 13 Nov 2025 13:51:14 -0500
Subject: [PATCH 1/2] Fix depth sorting of 3D surfaces in 2D scenes (GH-4475)

---
 manim/camera/camera.py | 39 ++++++++++++++++++++++++++++++++-------
 1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/manim/camera/camera.py b/manim/camera/camera.py
index cab8c5ac0f..d6be2d74f3 100644
--- a/manim/camera/camera.py
+++ b/manim/camera/camera.py
@@ -475,13 +475,38 @@ def get_mobjects_to_display(
                 use_z_index=self.use_z_index,
                 only_those_with_points=True,
             )
-            if excluded_mobjects:
-                all_excluded = extract_mobject_family_members(
-                    excluded_mobjects,
-                    use_z_index=self.use_z_index,
-                )
-                mobjects = list_difference_update(mobjects, all_excluded)
-        return list(mobjects)
+
+        if excluded_mobjects:
+            all_excluded = extract_mobject_family_members(
+                excluded_mobjects,
+                use_z_index=self.use_z_index,
+            )
+            mobjects = list_difference_update(mobjects, all_excluded)
+
+        mobject_list = list(mobjects)
+
+        # --- Depth sort for 3D-shaded mobjects (e.g. Surface faces) ---
+        def z_key(mob: Mobject) -> float:
+            # Only depth-sort “true 3D” mobjects, like Surface faces.
+            if not (hasattr(mob, "shade_in_3d") and getattr(mob, "shade_in_3d")):
+                # Non-3D mobjects keep their relative order (stable sort).
+                return float("inf")
+
+            # Prefer a dedicated reference point if available.
+            if hasattr(mob, "get_z_index_reference_point"):
+                ref = mob.get_z_index_reference_point()
+            else:
+                ref = mob.get_center()
+
+            # Larger z = closer to camera = should be drawn later.
+            return ref[2]
+
+        # Python’s sort is stable: non-3D mobjects stay in order,
+        # 3D ones get correctly sorted by depth.
+        mobject_list.sort(key=z_key)
+
+        return mobject_list
+
 
     def is_in_frame(self, mobject: Mobject) -> bool:
         """Checks whether the passed mobject is in

From 3e211685744cb9351df8a6db08da6c7a46b40317 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Thu, 13 Nov 2025 18:53:11 +0000
Subject: [PATCH 2/2] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 manim/camera/camera.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/manim/camera/camera.py b/manim/camera/camera.py
index d6be2d74f3..07e53cdb0e 100644
--- a/manim/camera/camera.py
+++ b/manim/camera/camera.py
@@ -488,7 +488,7 @@ def get_mobjects_to_display(
         # --- Depth sort for 3D-shaded mobjects (e.g. Surface faces) ---
         def z_key(mob: Mobject) -> float:
             # Only depth-sort “true 3D” mobjects, like Surface faces.
-            if not (hasattr(mob, "shade_in_3d") and getattr(mob, "shade_in_3d")):
+            if not (hasattr(mob, "shade_in_3d") and mob.shade_in_3d):
                 # Non-3D mobjects keep their relative order (stable sort).
                 return float("inf")
 
@@ -507,7 +507,6 @@ def z_key(mob: Mobject) -> float:
 
         return mobject_list
 
-
     def is_in_frame(self, mobject: Mobject) -> bool:
         """Checks whether the passed mobject is in
         frame or not.