ppb-vector

The 2D Vector Class for the PursuedPyBear project.

Install

You can install Vector2 pip package using

pip install 'ppb-vector'

Usage

Vector2 is an immutable 2D Vector. Instantiated as expected:

>>>> from ppb_vector import Vector2
>>> Vector2(3, 4)
Vector2(3, 4)

Implements many convenience features:

Unpacking

>>> x, y = Vector2(1, 3)
>>> print(x)
1
>>> print(y)
3

Addition

>>> Vector2(1, 0) + Vector2(0, 1)
Vector2(1, 1)

In addition to Vector2 addition also accepts vector-like objects such as tuple, list, and dict.

>>> Vector2(1, 1) + [1, 3]
Vector2(2, 4)

>>> Vector2(1, 1) + (2, 4)
Vector2(3, 5)

>>> Vector2(1, 1) + {"x": 3, "y": 5}
Vector2(4, 6)

Subtraction

>>> Vector2(3, 3) - Vector2(1, 1)
Vector2(2, 2)

As with addition, subtraction also takes vector-like objects.

>>> Vector2(3, 3) - [2, 1]
Vector2(1, 2)

>>> Vector2(3, 3) - (2, 1)
Vector2(1, 2)

>>> Vector2(3, 3) - {"x": 2, "y": 1}
Vector2(1, 2)

Equality

Vectors are equal if their members are equal.

>>> Vector2(1, 0) == Vector2(0, 1)
False

Scalar Multiplication

Multiply a Vector2 by a scalar to get a scaled Vector2

>>> Vector2(1, 1) * 3
Vector2(3, 3)

Dot Product

Multiply a Vector2 by another Vector2 to get the dot product.

>>> Vector2(1, 1) * Vector2(-1, -1)
-2

Vector Length

>>> Vector2(45, 60).length
75.0

Cross-product

Take the cross-product between two (2D) vectors. The result is expressed as a scalar, as it is known to lie on the z-axis.

>>> Vector(1, 0) ^ Vector(0, 1)
1

Access Values

Convenient access to Vector2 members via dot notation, indexes, or keys.

>>> my_vector = Vector2(2, 3)
>>> my_vector.x
2
>>> my_vector[1]
3
>>> my_vector["x"]
2

Also iterable for translation between Vector2 and other sequence types.

>>> tuple(Vector(2, 3))
(2, 3)

Negation

>>> -Vector2(1, 1)
Vector2(-1.0, -1.0)

Methods

Useful functions for game development.

rotate(deg)

Rotate a vector in relation to its own origin and return a new Vector2.

>>> Vector2(1, 0).rotate(90)
Vector2(0.0, 1.0)

Positive rotation is counter/anti-clockwise.

angle(vector)

Compute the angle between two vectors, expressed as a scalar in degrees.

>>> Vector(1, 0).angle(Vector(0, 1))
90

As with rotate(), angles are signed, and refer to a direct coordinate system (i.e. positive rotations are counter-clockwise).

normalize()

Return the normalized Vector2 for the given Vector2.

>>> Vector2(5, 5).normalize()
Vector2(0.7071067811865475, 0.7071067811865475)

truncate(scalar)

Scale a given Vector2 to length of scalar.

>>> Vector2(700, 500).truncate(5)
Vector2(4.068667356033675, 2.906190968595482)

Note that Vector2.normalize() is equivalent to Vector2.truncate(1).

>>> Vector2(200, 300).normalize()
Vector2(0.5547001962252291, 0.8320502943378436)
>>> Vector2(200, 300).scale(1)
Vector2(0.5547001962252291, 0.8320502943378436)

scale(scalar)

Scale given Vector2 to length of scalar.

>>> Vector2(7, 7).scale(5)
Vector2(3.5355339059327373, 3.5355339059327373)

Note that Vector2.scale is equivalent to Vector2.truncate when scalar is less than length.

>>> Vector2(3, 4).scale(4)
Vector2(2.4000000000000004, 3.2)
>>> Vector2(3, 4).truncate(4)
Vector2(2.4000000000000004, 3.2)
>>> Vector2(3, 4).scale(6)
Vector2(3.5999999999999996, 4.8)
>>> Vector2(3, 4).truncate(6)
Vector2(3, 4)

reflect(surface_normal)

Reflect a Vector2 based on a given surface normal.

>>> Vector2(5, 3).reflect(Vector2(-1, 0))
Vector2(-5, 3)
>>> Vector2(5, 3).reflect(Vector2(-1, -2).normalize())
Vector2(0.5999999999999996, -5.800000000000001)