From 7474ae17b054f3f2f56480d093afde19906ff29a Mon Sep 17 00:00:00 2001
From: Grant Sanderson <grant@3blue1brown.com>
Date: Tue, 20 Aug 2024 11:52:05 -0500
Subject: [PATCH] Change default to flat stroke, except in 3d situations

---
 manimlib/mobject/coordinate_systems.py       | 2 ++
 manimlib/mobject/geometry.py                 | 2 --
 manimlib/mobject/three_dimensions.py         | 2 ++
 manimlib/mobject/types/vectorized_mobject.py | 4 ++--
 manimlib/scene/scene.py                      | 4 +++-
 5 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/manimlib/mobject/coordinate_systems.py b/manimlib/mobject/coordinate_systems.py
index eb0c0b83..0c91492d 100644
--- a/manimlib/mobject/coordinate_systems.py
+++ b/manimlib/mobject/coordinate_systems.py
@@ -530,6 +530,7 @@ class ThreeDAxes(Axes):
         z_axis_config: dict = dict(),
         z_normal: Vect3 = DOWN,
         depth: float | None = None,
+        flat_stroke: bool = False,
         **kwargs
     ):
         Axes.__init__(self, x_range, y_range, **kwargs)
@@ -553,6 +554,7 @@ class ThreeDAxes(Axes):
         self.z_axis.shift(self.x_axis.n2p(0))
         self.axes.add(self.z_axis)
         self.add(self.z_axis)
+        self.set_flat_stroke(flat_stroke)
 
     def get_all_ranges(self) -> list[Sequence[float]]:
         return [self.x_range, self.y_range, self.z_range]
diff --git a/manimlib/mobject/geometry.py b/manimlib/mobject/geometry.py
index e1151aed..2f1a4730 100644
--- a/manimlib/mobject/geometry.py
+++ b/manimlib/mobject/geometry.py
@@ -642,7 +642,6 @@ class Arrow(Line):
         end: Vect3 | Mobject,
         stroke_color: ManimColor = GREY_A,
         stroke_width: float = 5,
-        flat_stroke: bool = True,
         buff: float = 0.25,
         tip_width_ratio: float = 5,
         tip_len_to_width: float = 0.0075,
@@ -660,7 +659,6 @@ class Arrow(Line):
             start, end,
             stroke_color=stroke_color,
             stroke_width=stroke_width,
-            flat_stroke=flat_stroke,
             buff=buff,
             **kwargs
         )
diff --git a/manimlib/mobject/three_dimensions.py b/manimlib/mobject/three_dimensions.py
index d29b7ec2..73daa58a 100644
--- a/manimlib/mobject/three_dimensions.py
+++ b/manimlib/mobject/three_dimensions.py
@@ -38,6 +38,7 @@ class SurfaceMesh(VGroup):
         normal_nudge: float = 1e-2,
         depth_test: bool = True,
         joint_type: str = 'no_joint',
+        flat_stroke: bool = False,
         **kwargs
     ):
         self.uv_surface = uv_surface
@@ -49,6 +50,7 @@ class SurfaceMesh(VGroup):
             stroke_width=stroke_width,
             depth_test=depth_test,
             joint_type=joint_type,
+            flat_stroke=flat_stroke,
             **kwargs
         )
 
diff --git a/manimlib/mobject/types/vectorized_mobject.py b/manimlib/mobject/types/vectorized_mobject.py
index dc2d8e9d..3ead48a8 100644
--- a/manimlib/mobject/types/vectorized_mobject.py
+++ b/manimlib/mobject/types/vectorized_mobject.py
@@ -90,7 +90,7 @@ class VMobject(Mobject):
         long_lines: bool = False,
         # Could also be "no_joint", "bevel", "miter"
         joint_type: str = "auto",
-        flat_stroke: bool = False,
+        flat_stroke: bool = True,
         use_simple_quadratic_approx: bool = False,
         # Measured in pixel widths
         anti_alias_width: float = 1.5,
@@ -393,7 +393,7 @@ class VMobject(Mobject):
         return self.get_stroke_opacity()
 
     def set_flat_stroke(self, flat_stroke: bool = True, recurse: bool = True) -> Self:
-        self.set_uniform(recurse, flat_stroke=flat_stroke)
+        self.set_uniform(recurse, flat_stroke=float(flat_stroke))
         return self
 
     def get_flat_stroke(self) -> bool:
diff --git a/manimlib/scene/scene.py b/manimlib/scene/scene.py
index c2a05bb7..ea9caf5c 100644
--- a/manimlib/scene/scene.py
+++ b/manimlib/scene/scene.py
@@ -1049,8 +1049,10 @@ class ThreeDScene(Scene):
     default_frame_orientation = (-30, 70)
     always_depth_test = True
 
-    def add(self, *mobjects: Mobject, set_depth_test: bool = True):
+    def add(self, *mobjects: Mobject, set_depth_test: bool = True, perp_stroke: bool = True):
         for mob in mobjects:
             if set_depth_test and not mob.is_fixed_in_frame() and self.always_depth_test:
                 mob.apply_depth_test()
+            if isinstance(mob, VMobject) and mob.has_stroke() and perp_stroke:
+                mob.set_flat_stroke(False)
         super().add(*mobjects)