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Add c# samples to Vector Math
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@@ -63,10 +63,16 @@ coordinate notation. For example, in Godot the origin is the top-left
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corner of the screen, so to place a 2D node named ``Node2D`` 400 pixels to the right and
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300 pixels down, use the following code:
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::
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.. tabs::
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.. code-tab:: gdscript GDScript
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$Node2D.position = Vector2(400, 300)
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.. code-tab:: csharp
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var node2D = (Node2D) GetNode("Node2D");
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node2D.Position = new Vector2(400, 300);
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Godot supports both :ref:`Vector2 <class_Vector2>` and
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:ref:`Vector3 <class_Vector3>` for 2D and 3D usage respectively. The same
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mathematical rules discussed in this article apply for both types.
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@@ -75,7 +81,8 @@ mathematical rules discussed in this article apply for both types.
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The individual components of the vector can be accessed directly by name.
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::
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.. tabs::
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.. code-tab:: gdscript GDScript
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# create a vector with coordinates (2, 5)
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var a = Vector2(2, 5)
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@@ -84,14 +91,28 @@ The individual components of the vector can be accessed directly by name.
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b.x = 3
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b.y = 1
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.. code-tab:: csharp
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// create a vector with coordinates (2, 5)
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var a = new Vector2(2, 5);
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// create a vector and assign x and y manually
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var b = new Vector2();
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b.x = 3;
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b.y = 1;
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- Adding vectors
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When adding or subtracting two vectors, the corresponding components are added:
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::
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.. tabs::
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.. code-tab:: gdscript GDScript
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var c = a + b # (2, 5) + (3, 1) = (5, 6)
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.. code-tab:: csharp
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var c = a + b; // (2, 5) + (3, 1) = (5, 6)
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We can also see this visually by adding the second vector at the end of
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the first:
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@@ -106,11 +127,17 @@ Note that adding ``a + b`` gives the same result as ``b + a``.
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A vector can be multiplied by a **scalar**:
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::
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.. tabs::
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.. code-tab:: gdscript GDScript
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var c = a * 2 # (2, 5) * 2 = (4, 10)
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var d = b / 3 # (3, 6) / 3 = (1, 2)
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.. code-tab:: csharp
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var c = a * 2; // (2, 5) * 2 = (4, 10)
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var d = b / 3; // (3, 6) / 3 = (1, 2)
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.. image:: img/vector_mult1.png
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.. note:: Multiplying a vector by a scalar does not change its direction,
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@@ -158,20 +185,34 @@ Normalization
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preserving its direction. This is done by dividing each of its components
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by its magnitude:
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::
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.. tabs::
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.. code-tab:: gdscript GDScript
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var a = Vector2(2, 4)
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var m = sqrt(a.x*a.x + a.y*a.y) # get magnitude "m" using the Pythagorean theorem
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a.x /= m
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a.y /= m
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.. code-tab:: csharp
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var a = new Vector2(2, 4);
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var m = Mathf.Sqrt(a.x*a.x + a.y*a.y); // get magnitude "m" using the Pythagorean theorem
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a.x /= m;
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a.y /= m;
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Because this is such a common operation, ``Vector2`` and ``Vector3`` provide
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a method for normalizing:
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::
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.. tabs::
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.. code-tab:: gdscript GDScript
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a = a.normalized()
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.. code-tab:: csharp
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a = a.Normalized();
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.. warning:: Because normalization involves dividing by the vector's length,
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you cannot normalize a vector of length ``0``. Attempting to
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do so will result in an error.
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@@ -196,14 +237,28 @@ Godot, the :ref:`Vector2 <class_Vector2>` class has a ``bounce()`` method
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to handle this. Here is a GDScript example of the diagram above using a
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:ref:`KinematicBody2D <class_KinematicBody2D>`:
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::
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var collision = move_and_collide(velocity * delta) # object "collision" contains information about the collision
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.. tabs::
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.. code-tab:: gdscript GDScript
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# object "collision" contains information about the collision
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var collision = move_and_collide(velocity * delta)
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if collision:
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var reflect = collision.remainder.bounce(collision.normal)
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velocity = velocity.bounce(collision.normal)
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move_and_collide(reflect)
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.. code-tab:: csharp
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// KinematicCollision2D contains information about the collision
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KinematicCollision2D collision = MoveAndCollide(_velocity * delta);
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if (collision != null)
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{
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var reflect = collision.Remainder.Bounce(collision.Normal);
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_velocity = _velocity.Bounce(collision.Normal);
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MoveAndCollide(reflect);
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}
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Dot product
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~~~~~~~~~~~
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@@ -227,11 +282,17 @@ and
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However, in most cases it is easiest to use the built-in method. Note that
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the order of the two vectors does not matter:
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::
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.. tabs::
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.. code-tab:: gdscript GDScript
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var c = a.dot(b)
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var d = b.dot(a) # these are equivalent
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.. code-tab:: csharp
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float c = a.Dot(b);
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float d = b.Dot(a); // these are equivalent
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The dot product is most useful when used with unit vectors, making the
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first formula reduce to just ``cosθ``. This means we can use the dot
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product to tell us something about the angle between two vectors:
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@@ -259,12 +320,21 @@ the player.
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In GDScript it would look like this:
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::
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.. tabs::
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.. code-tab:: gdscript GDScript
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var AP = (P - A).normalized()
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if AP.dot(fA) > 0:
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print("A sees P!")
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.. code-tab:: csharp
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var AP = (P - A).Normalized();
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if (AP.Dot(fA) > 0)
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{
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GD.Print("A sees P!");
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}
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Cross product
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~~~~~~~~~~~~~
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@@ -281,19 +351,34 @@ If two vectors are parallel, the result of their cross product will be null vect
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The cross product is calculated like this:
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::
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.. tabs::
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.. code-tab:: gdscript GDScript
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var c = Vector3()
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c.x = (a.y * b.z) - (a.z * b.y)
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c.y = (a.z * b.x) - (a.x * b.z)
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c.z = (a.x * b.y) - (a.y * b.x)
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.. code-tab:: csharp
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var c = new Vector3();
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c.x = (a.y * b.z) - (a.z * b.y);
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c.y = (a.z * b.x) - (a.x * b.z);
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c.z = (a.x * b.y) - (a.y * b.x);
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In GDScript, you can use the built-in method:
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::
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.. tabs::
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.. code-tab:: gdscript GDScript
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var c = a.cross(b)
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.. code-tab:: csharp
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var c = a.Cross(b);
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.. note:: In the cross product, order matters. ``a.cross(b)`` does not
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give the same result as ``b.cross(a)``. The resulting vectors
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point in **opposite** directions.
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@@ -308,7 +393,8 @@ subtraction to find two edges ``AB`` and ``AC``. Using the cross product,
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Here is a function to calculate a triangle's normal in GDScript:
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::
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.. tabs::
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.. code-tab:: gdscript GDScript
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func get_triangle_normal(a, b, c):
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# find the surface normal given 3 vertices
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@@ -317,6 +403,17 @@ Here is a function to calculate a triangle's normal in GDScript:
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var normal = side1.cross(side2)
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return normal
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.. code-tab:: csharp
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Vector3 GetTriangleNormal(Vector3 a, Vector3 b, Vector3 c)
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{
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// find the surface normal given 3 vertices
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var side1 = b - a;
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var side2 = c - a;
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var normal = side1.Cross(side2);
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return normal;
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}
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Pointing to a Target
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--------------------
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