Ensure that start and end points are stored as float values in Line3D (#4080)

* fixed problem with type conversions in Line3D

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* fixed broken test and Arrow3D

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* Update manim/mobject/three_d/three_dimensions.py

Co-authored-by: Aarush Deshpande <110117391+JasonGrace2282@users.noreply.github.com>

* Update manim/mobject/three_d/three_dimensions.py

Co-authored-by: Aarush Deshpande <110117391+JasonGrace2282@users.noreply.github.com>

* Delete unnecessary file

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* fixed typo in variable nam

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Aarush Deshpande <110117391+JasonGrace2282@users.noreply.github.com>

Author: 3 people

manim/mobject/three_d/three_dimensions.py

@@ -936,6 +936,10 @@ def __init__(
     ):
         self.thickness = thickness
         self.resolution = (2, resolution) if isinstance(resolution, int) else resolution
+
+        start = np.array(start, dtype=np.float64)
+        end = np.array(end, dtype=np.float64)
+
         self.set_start_and_end_attrs(start, end, **kwargs)
         if color is not None:
             self.set_color(color)
@@ -1193,8 +1197,9 @@ def __init__(
             height=height,
             **kwargs,
         )
-        self.cone.shift(end)
-        self.end_point = VectorizedPoint(end)
+        np_end = np.asarray(end, dtype=np.float64)
+        self.cone.shift(np_end)
+        self.end_point = VectorizedPoint(np_end)
         self.add(self.end_point, self.cone)
         self.set_color(color)
 

tests/test_graphical_units/test_threed.py

@@ -164,11 +164,34 @@ def param_surface(u, v):
 
 
 def test_get_start_and_end_Arrow3d():
-    start, end = ORIGIN, np.array([2, 1, 0])
+    start, end = ORIGIN, np.array([2, 1, 0], dtype=np.float64)
     arrow = Arrow3D(start, end)
     assert np.allclose(arrow.get_start(), start, atol=0.01), (
         "start points of Arrow3D do not match"
     )
     assert np.allclose(arrow.get_end(), end, atol=0.01), (
         "end points of Arrow3D do not match"
     )
+
+
+def test_type_conversion_in_Line3D():
+    start, end = [0, 0, 0], [1, 1, 1]
+    line = Line3D(start, end)
+    type_table = [type(item) for item in [*line.get_start(), *line.get_end()]]
+    bool_table = [t == np.float64 for t in type_table]
+    assert all(bool_table), "Types of start and end points are not np.float64"
+
+
+def test_type_conversion_in_Arrow3D():
+    start, end = [0, 0, 0], [1, 1, 1]
+    arrow = Arrow3D(start, end)
+    type_table = [type(item) for item in [*arrow.get_start(), *arrow.get_end()]]
+    bool_table = [t == np.float64 for t in type_table]
+    assert all(bool_table), "Types of start and end points are not np.float64"
+
+    assert np.allclose(arrow.get_start(), start, atol=0.01), (
+        "start points of Arrow3D do not match"
+    )
+    assert np.allclose(arrow.get_end(), end, atol=0.01), (
+        "end points of Arrow3D do not match"
+    )