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Clarify the difference between Vector2/3's reflect() and bounce() #68392

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Clarify the difference between Vector2/3's reflect() and bounce() #68392

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4 changes: 3 additions & 1 deletion doc/classes/Vector2.xml
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Original file line number Diff line number Diff line change
Expand Up @@ -99,7 +99,8 @@
<return type="Vector2" />
<param index="0" name="n" type="Vector2" />
<description>
Returns the vector "bounced off" from a plane defined by the given normal.
Returns the vector "bounced off" from a plane defined by the given normal [param n].
[b]Note:[/b] [method bounce] performs [i]physical[/i] reflection, as opposed to [method reflect] which performs [i]mathematical[/i] reflection. Double-check which method you actually need to use, as other engines may use these terms differently.
</description>
</method>
<method name="ceil" qualifiers="const">
Expand Down Expand Up @@ -311,6 +312,7 @@
<param index="0" name="n" type="Vector2" />
<description>
Returns the vector reflected (i.e. mirrored, or symmetric) over a line defined by the given direction vector [param n].
[b]Note:[/b] [method reflect] performs [i]mathematical[/i] reflection, as opposed to [method bounce] which performs [i]physical[/i] reflection. Double-check which method you actually need to use, as other engines may use these terms differently.
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performs [i]mathematical[/i] reflection

I'm not sure that this is properly called "mathematical" reflection. From what I can see, "n" is always the normal vector (i.e. pointing perpendicular from the surface). While in this case "n" is not the normal, but the plane itself.

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A little more insight, the wikipedia page for "reflection (mathematics)" gives a definition for reflection the same as what we use for reflection, but calls the parameter "line" instead of "normal". (https://en.wikipedia.org/wiki/Reflection_(mathematics))

Bounce on the other hand, is a mathematical reflection over a normal. It is also equivalent to -vec.reflect()

Instead of calling them "mathematical reflection" and "physical reflection" I would highlight that you are reflecting over a normal vector perpendicular to the plane, or a vector describing the plane itself. So you are either "bouncing off a surface with normal n" or you are "reflecting across the surface n"

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So you are either "bouncing off a surface with normal n"

Isn't that what bounce() does?

</description>
</method>
<method name="rotated" qualifiers="const">
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6 changes: 4 additions & 2 deletions doc/classes/Vector3.xml
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Original file line number Diff line number Diff line change
Expand Up @@ -75,7 +75,8 @@
<return type="Vector3" />
<param index="0" name="n" type="Vector3" />
<description>
Returns the vector "bounced off" from a plane defined by the given normal.
Returns the vector "bounced off" from a plane defined by the given normal [param n].
[b]Note:[/b] [method bounce] performs [i]physical[/i] reflection, as opposed to [method reflect] which performs [i]mathematical[/i] reflection.
</description>
</method>
<method name="ceil" qualifiers="const">
Expand Down Expand Up @@ -294,7 +295,8 @@
<return type="Vector3" />
<param index="0" name="n" type="Vector3" />
<description>
Returns this vector reflected from a plane defined by the given normal.
Returns the vector reflected (i.e. mirrored, or symmetric) over a plane defined by the given direction vector [param n].
[b]Note:[/b] [method reflect] performs [i]mathematical[/i] reflection, as opposed to [method bounce] which performs [i]physical[/i] reflection. Double-check which method you actually need to use, as other engines may use these terms differently.
</description>
</method>
<method name="rotated" qualifiers="const">
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