Py5Vector#

Class to describe a 2D, 3D, or 4D vector.

Examples#

 1import numpy as np
 2
 3v1 = py5.Py5Vector(1, 2, 3)
 4print(v1)
 5# Py5Vector3D(1., 2., 3.)
 6
 7v2 = py5.Py5Vector(dim=4)
 8print(v2)
 9# Py5Vector4D(0., 0., 0., 0.)
10
11v3 = py5.Py5Vector(1 / 3, 1 / 7, dtype=np.float16)
12print(v3)
13# Py5Vector2D(0.3333, 0.1428)
14
15v4 = py5.Py5Vector([1, 2, 3])
16print(v4)
17# Py5Vector3D(1., 2., 3.)
18
19v5 = py5.Py5Vector(v4, 0)
20print(v5)
21# Py5Vector4D(1., 2., 3., 0.)
22
23arr = np.array([1., 2., 3.])
24v6 = py5.Py5Vector(arr, copy=False)
25print(v6)
26# Py5Vector3D(1., 2., 3.)

Description#

Class to describe a 2D, 3D, or 4D vector. A vector is an entity that has both a magnitude and a direction. This datatype stores the components of the vector as a set of coordinates. A 3D vector, for example, has Py5Vector.x, Py5Vector.y, and Py5Vector.z values that quantify the vector along the 3 dimensions X, Y, and Z. The magnitude and direction can be accessed via the properties Py5Vector.mag and Py5Vector.heading.

In many of the py5 examples, you will see Py5Vector used to describe a position, velocity, or acceleration. For example, if you consider a rectangle moving across the screen, at any given instant it has a position (a vector that points from the origin to its location), a velocity (the rate at which the object’s position changes per time unit, expressed as a vector), and acceleration (the rate at which the object’s velocity changes per time unit, expressed as a vector).

The Py5Vector class works well with numpy and in most cases you will be able to do math operations that combine vectors and numpy arrays.

To create a vector, you can write code like v = Py5Vector(1, 2, 3), which would create a 3D vector with the x, y, and z values equal to 1, 2, and 3. To create a vector of zeros, omit the vector values and specify the desired dimension with the dim parameter, such as v = Py5Vector(dim=4).

Internally, Py5Vector stores the vector values in a numpy array. By default, the data type (dtype) of that numpy array is the default float size for your computer, which is typically a 64 bit float, or np.float64. To create a vector with a different float size, pass your desired numpy float dtype to the dtype parameter, like v3 = py5.Py5Vector(1 / 3, 1 / 7, dtype=np.float16).

When creating a new Py5Vector, the initial vector values need not be discrete values. You can provide a list of numbers, a numpy array, or another Py5Vector. For example, v4 = py5.Py5Vector([1, 2, 3]) creates a Py5Vector from a list, and v5 = py5.Py5Vector(v4, 0) creates a 4D Py5Vector from a 3D Py5Vector and a constant value.

When creating a new Py5Vector from a single numpy array, py5 will by default create its own copy of the numpy array for the Py5Vector to use. To instruct py5 to instead use the same numpy array and share its data with provided array, set the copy parameter to False, such as v6 = py5.Py5Vector(arr, copy=False).

The following methods and fields are provided:

  • angle_between(): Measure the angle between two vectors.

  • astype(): Create a new Py5Vector instance with a specified numpy dtype.

  • copy: Create an identical copy of this Py5Vector instance.

  • cross(): Calculate the vector cross product of two 3D vectors.

  • data: Numpy array used to store the vector’s data values.

  • dim: The vector’s dimension.

  • dist(): Calculate the distance between two vectors.

  • dot(): Calculate the dot product between two vectors.

  • dtype: Vector data type.

  • from_heading(): Class method to create a new vector with a given heading, measured in radians.

  • heading: The vector’s heading, measured in radians.

  • lerp(): Calculates a vector between two vectors at a specific increment.

  • mag: The vector’s magnitude.

  • mag_sq: The square of the vector’s magnitude.

  • norm: Normalized copy of the vector.

  • normalize(): Normalize the vector by setting the vector’s magnitude to 1.0.

  • random(): Create a new vector with random values.

  • rotate(): Rotate vector by a specified angle.

  • rotate_around(): Rotate around an arbitrary 3D vector.

  • set_heading(): Align vector with the specified heading.

  • set_limit(): Constrain the vector’s magnitude to a specified value.

  • set_mag(): Set the vector’s magnitude.

  • set_mag_sq(): Set the vector’s squared magnitude.

  • tolist(): Return the vector’s values as a list.

  • w: The vector’s w dimension value.

  • x: The vector’s x dimension value.

  • y: The vector’s y dimension value.

  • z: The vector’s z dimension value.

Updated on January 16, 2022 16:51:21pm UTC