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python for unity with code examples

Ahmed Zakaria

Python is one of the most popular programming languages in the world, and it has become increasingly important in video game development. Python is easy to learn and use, with a clean syntax and a wide range of libraries and frameworks for various tasks. Unity, on the other hand, is a popular game engine used by developers to build games for multiple platforms, including desktop, mobile, and consoles. The combination of these two can lead to some extraordinary opportunities. Python for Unity is a package that allows developers to use Python scripting in the Unity game engine. With Python for Unity, it is possible to create complex features and logic that would otherwise be difficult or time-consuming to implement in C#.

Python for Unity is not a built-in feature of Unity. Therefore you need to download and install the Python interpreter and the Python for Unity package separately. Once you have both installed, you can use Python in Unity. In this article, we will explore how to use Python scripts in Unity with plenty of examples.

  1. Setting up Python for Unity
    Before we dive into Python coding in Unity, let's take a look at how to set up Python for Unity. First, you need to install the Python interpreter. You can download Python from the official website, python.org. Once you have downloaded and installed Python, you need to install the Python for Unity package.

The easiest way to install Python for Unity package is by using the Package Manager in Unity. Open the Package Manager by clicking on "Window" > "Package Manager". In the Package Manager, search for "Python for Unity". Select the package, and click the "Install" button. The package will be installed automatically.

  1. Creating a Python Script

To create a Python script in Unity, you need to create a new C# script and then rename it to have a .py extension. Once you have renamed the file, Unity will recognize it as a Python script.

Now let's create a Python script that will display a message on the screen. First, we need to create a Python script file. Right-click in the Project window, select "Create" > "Python Script" and name the file "hello_world.py". Open the script file and add the following code:

import UnityEngine

def print_message():
    print("Hello World!")
    
print_message()

Save the script and return to the Unity Editor. You should now see the "hello_world.py" file in your Project window.

  1. Executing a Python Script

To run a Python script in Unity, we need to create a C# script that will execute the Python script. Create a new C# script in the Unity Editor and name it "PythonScriptRunner.cs". Add the following code to the script:

using UnityEngine;
using System.IO;
using IronPython.Hosting;

public class PythonScriptRunner : MonoBehaviour
{
    void Start()
    {
        var engine = Python.CreateEngine();
        var searchPaths = engine.GetSearchPaths();
        var pythonPath = Application.persistentDataPath;
        searchPaths.Add(pythonPath);
        engine.SetSearchPaths(searchPaths);
 
        var scriptSource = engine.CreateScriptSourceFromFile(Application.persistentDataPath + "/hello_world.py");
        scriptSource.Execute();
    }
}

The above code will create a Python engine, set the search paths, and execute the "hello_world.py" script.

Next, attach the "PythonScriptRunner.cs" script to a GameObject in your scene. Once you run the scene, you should see "Hello World!" displayed in the console.

  1. Accessing Unity API from Python

One of the main benefits of using Python in Unity is the ability to access Unity's API from Python. With Python, it is possible to manipulate and create Unity objects, modify scenes, and implement gameplay logic.

Let's take a look at an example of how to access the Unity API from Python. In this example, we will create a new GameObject in Unity using Python. First, create a new Python script file and name it "create_cube.py". Add the following code to the script:

import UnityEngine

def create_cube():
    cube = UnityEngine.GameObject.CreatePrimitive(UnityEngine.PrimitiveType.Cube)
    cube.transform.position = UnityEngine.Vector3(0, 0, 0)

create_cube()

Next, create a new C# script file and name it "CreateCube.cs". Add the following code to the script:

using UnityEngine;
using System.IO;
using IronPython.Hosting;

public class CreateCube : MonoBehaviour
{
    void Start()
    {
        var engine = Python.CreateEngine();
        var searchPaths = engine.GetSearchPaths();
        var pythonPath = Application.persistentDataPath;
        searchPaths.Add(pythonPath);
        engine.SetSearchPaths(searchPaths);
 
        var scriptSource = engine.CreateScriptSourceFromFile(Application.persistentDataPath + "/create_cube.py");
        scriptSource.Execute();
    }
}

Attach the "CreateCube.cs" script to a GameObject in your scene. When you run the scene, a new cube will be created.

  1. Using Python to Control Unity Objects

In this example, we will use Python to control the position and rotation of a Unity GameObject. Create a new Python script file and name it "move_object.py". Add the following code to the script:

import UnityEngine

def move_object():
    obj = UnityEngine.GameObject.Find("Cube")
    obj.transform.position = UnityEngine.Vector3(2, 0, 0)
    obj.transform.Rotate(0,10,0)
    print("Object moved successfully...")

move_object()

This script will find the "Cube" GameObject in the scene, set its position to (2, 0, 0), and rotate it by 10 degrees around the Y-axis.

Create a new C# script file and name it "MoveObject.cs". Add the following code to the script:

using UnityEngine;
using System.IO;
using IronPython.Hosting;

public class MoveObject : MonoBehaviour
{
    void Start()
    {
        var engine = Python.CreateEngine();
        var searchPaths = engine.GetSearchPaths();
        var pythonPath = Application.persistentDataPath;
        searchPaths.Add(pythonPath);
        engine.SetSearchPaths(searchPaths);
 
        var scriptSource = engine.CreateScriptSourceFromFile(Application.persistentDataPath + "/move_object.py");
        scriptSource.Execute();
    }
}

Attach the "MoveObject.cs" script to a GameObject in your scene. When you run the scene, the cube will be moved to (2, 0, 0), and rotated by 10 degrees around the Y-axis.

  1. Using Python for Game Logic

In addition to manipulating objects in the scene, Python can also be used for game logic. In this example, we will use Python to create a simple game. Create a new Python script file and name it "simple_game.py". Add the following code to the script:

import UnityEngine
import random

score = 0
spawn_time = 1.0

def spawn_cube():
    x = random.randrange(-10, 10)
    y = random.randrange(0, 5)
    z = random.randrange(-10, 10)
    cube = UnityEngine.GameObject.CreatePrimitive(UnityEngine.PrimitiveType.Cube)
    cube.transform.position = UnityEngine.Vector3(x, y, z)
    return cube

def check_input():
    if (Input.GetKey(KeyCode.Space)):
        return True
    else:
        return False

def game_loop():
    global score
    global spawn_time
    while True:
        cube = spawn_cube()
        while True:
            if check_input():
                score += 1
                print("Score:", score)
                Destroy(cube)
                break
            if (cube.transform.position.y < 0):
                print("Game Over!")
                return
            cube.transform.Translate(UnityEngine.Vector3.down * Time.deltaTime)
            yield
        spawn_time -= 0.01
        yield WaitForSeconds(spawn_time)
 
game_loop()

The above code will spawn a cube at a random position and move it down towards the ground. The player must press the "Space" key to destroy the cube and earn a point. If the cube reaches the ground without being destroyed, the game ends.

Create a new C# script file and name it "SimpleGame.cs". Add the following code:

using UnityEngine;
using System.IO;
using IronPython.Hosting;

public class SimpleGame : MonoBehaviour
{
    private IEnumerator coroutine;

    void Start()
    {
        var engine = Python.CreateEngine();
        var searchPaths = engine.GetSearchPaths();
        var pythonPath = Application.persistentDataPath;
        searchPaths.Add(pythonPath);
        engine.SetSearchPaths(searchPaths);
 
        var scriptSource = engine.CreateScriptSourceFromFile(Application.persistentDataPath + "/simple_game.py");
        var scope = engine.CreateScope();
        scope.SetVariable("Destroy", new UnityEngine.Object.DestroyDelegate(UnityEngine.Object.Destroy));
        scope.SetVariable("Input", typeof(UnityEngine.Input));
        scope.SetVariable("Time", typeof(UnityEngine.Time));
        scope.SetVariable("WaitForSeconds", new UnityEngine.WaitForSecondsDelegate(UnityEngine.WaitForSeconds));
        scriptSource.Execute(scope);

        coroutine = (IEnumerator)scope.GetVariable("game_loop").Invoke(scope);
        StartCoroutine(coroutine);
    }

    void OnDestroy()
    {
        StopCoroutine(coroutine);
    }
}

Attach the "SimpleGame.cs" script to a GameObject in the scene. When you run the scene, the game will start. Press the "Space" key to destroy cubes and earn points.

In conclusion, Python for Unity is an excellent tool that can help developers create complex scripts and logic for their games. With Python, you have access to a wide range of libraries and frameworks that can help you develop faster and more efficiently. In this article, we have seen how to use Python in Unity with many examples – access Unity API from Python, manipulate Unity objects, and implement game logic. However, this is just the tip of the iceberg. Python has much more to offer for game development. If you're looking to create complex features in your game, Python for Unity is a fantastic tool to have in your toolbox.

I'd be happy to provide more detail on the previous topics.

  1. Setting Up Python for Unity
    It's essential to set up Python for Unity correctly before beginning to write scripts. While Unity does not come prepackaged with Python support, installing it is quite easy.

First, you need to download and install Python from the official website, python.org. You should download the latest version of Python 3, as it is the most widely used version and has the most resources available online.

Once you have installed Python, you need to install the Python for Unity package. You can do this by opening the Package Manager in Unity and then searching for "Python for Unity." Select the package and click the "Install" button.

After you have installed the Python for Unity package, you're ready to start creating Python scripts in Unity.

  1. Creating a Python Script
    Creating a Python script in Unity is quite simple. All you need to do is create a new C# script and then rename it with a .py extension. Once you have done this, Unity recognises the file as a Python script.

To create a simple "hello world" Python script, open the Python script file and add the following code to it:

def hello_world():
    print("Hello World!")

hello_world()

This script defines a function "hello_world" that prints the string "Hello World!" to the console and then calls the function.

  1. Executing a Python Script
    After you have created a Python script, you need to create a C# script that will execute the Python script. In Unity, create a new C# script, name it "PythonScriptRunner.cs", and add the following code to it:
void Start()
{
    var engine = IronPython.Hosting.Python.CreateEngine();
    var scope = engine.CreateScope();
 
    // Run the script
    var source = engine.CreateScriptSourceFromFile(Application.dataPath + "/hello_world.py");
    source.Execute(scope);
}

This code creates an instance of the Python engine and then executes the "hello_world.py" script, which you have created earlier. After executing the script, Unity will display "Hello World!" in the Console.

  1. Accessing Unity API from Python
    With Python, you can access Unity's API and manipulate objects in the scene. Here is an example of a Python script that creates a new cube in the scene:
import UnityEngine
 
def create_cube():
    cube = UnityEngine.GameObject.CreatePrimitive(UnityEngine.PrimitiveType.Cube)
    cube.transform.position = UnityEngine.Vector3(0, 0, 0)
 
create_cube()

This script defines a function "create_cube" that creates a new Unity cube object and sets its position to (0, 0, 0).

To access Unity's API from Python, you need to add references to the required namespaces in your C# script. Here is an example of a C# script that executes the "create_cube.py" script:

using UnityEngine;
using System.IO;
using IronPython.Hosting;
 
public class PythonScriptRunner : MonoBehaviour
{
    void Start()
    {
        var engine = Python.CreateEngine();
        var searchPaths = engine.GetSearchPaths();
        var pythonPath = Application.persistentDataPath;
        searchPaths.Add(pythonPath);
        engine.SetSearchPaths(searchPaths);
 
        var scriptSource = engine.CreateScriptSourceFromFile(Application.persistentDataPath + "/create_cube.py");
        scriptSource.Execute();
    }
}

This script creates an instance of the Python engine, sets the search paths to the persistent data path of the project, and then executes the "create_cube.py" script.

  1. Using Python to Control Unity Objects
    Python can also be used to manipulate Unity objects. Here's an example of a Python script that moves a cube:
import UnityEngine
 
def move_cube():
    cube = UnityEngine.GameObject.Find("Cube")
    cube.transform.position = UnityEngine.Vector3(2, 0, 0)

move_cube()

This script finds the "Cube" object in the scene and moves it to (2, 0, 0).

To use a Python script to control Unity objects, you need to use a C# script to execute the Python script. Here's an example of a C# script that executes the "move_cube.py" script:

using UnityEngine;
using System.IO;
using IronPython.Hosting;
 
public class PythonScriptRunner : MonoBehaviour
{
    void Start()
    {
        var engine = Python.CreateEngine();
        var searchPaths = engine.GetSearchPaths();
        var pythonPath = Application.persistentDataPath;
        searchPaths.Add(pythonPath);
        engine.SetSearchPaths(searchPaths);
 
        var scriptSource = engine.CreateScriptSourceFromFile(Application.persistentDataPath + "/move_cube.py");
        scriptSource.Execute();
    }
}

This script creates an instance of the Python engine, sets the search paths to the persistent data path of the project, and then executes the "move_cube.py" script.

  1. Using Python for Game Logic
    Python is also great for implementing game logic. Here's an example of a Python script that implements a simple game:
import UnityEngine
import random
 
score = 0
spawn_time = 1.0

def spawn_cube():
    x = random.randrange(-10, 10)
    y = random.randrange(0, 5)
    z = random.randrange(-10, 10)
    cube = UnityEngine.GameObject.CreatePrimitive(UnityEngine.PrimitiveType.Cube)
    cube.transform.position = UnityEngine.Vector3(x, y, z)
    return cube
 
def check_input():
    if (Input.GetKey(KeyCode.Space)):
        return True
    else:
        return False
 
def game_loop():
    global score
    global spawn_time
    while True:
        cube = spawn_cube()
        while True:
            if check_input():
                score += 1
                print("Score:", score)
                Destroy(cube)
                break
            if (cube.transform.position.y < 0):
                print("Game Over!")
                return
            cube.transform.Translate(UnityEngine.Vector3.down * Time.deltaTime)
            yield
        spawn_time -= 0.01
        yield WaitForSeconds(spawn_time)
 
game_loop()

This script spawns cubes randomly and moves them down towards the ground. The player must press the "Space" key to destroy the cube and earn a point. If the cube reaches the ground without being destroyed, the game ends.

To execute a Python script that implements game logic, you need to create a C# script that executes the Python script. Here's an example of a C# script that executes the "simple_game.py" script:

using UnityEngine;
using System.IO;
using IronPython.Hosting;
 
public class PythonScriptRunner : MonoBehaviour
{
    private IEnumerator coroutine;
 
    void Start()
    {
        var engine = Python.CreateEngine();
        var searchPaths = engine.GetSearchPaths();
        var pythonPath = Application.persistentDataPath;
        searchPaths.Add(pythonPath);
        engine.SetSearchPaths(searchPaths);
 
        var scriptSource = engine.CreateScriptSourceFromFile(Application.persistentDataPath + "/simple_game.py");
        var scope = engine.CreateScope();
        scope.SetVariable("Destroy", new UnityEngine.Object.DestroyDelegate(UnityEngine.Object.Destroy));
        scope.SetVariable("Input", typeof(UnityEngine.Input));
        scope.SetVariable("Time", typeof(UnityEngine.Time));
        scope.SetVariable("WaitForSeconds", new UnityEngine.WaitForSecondsDelegate(UnityEngine.WaitForSeconds));
        scriptSource.Execute(scope);

        coroutine = (IEnumerator)scope.GetVariable("game_loop").Invoke(scope);
        StartCoroutine(coroutine);
    }
 
    void OnDestroy()
    {
        StopCoroutine(coroutine);
    }
}

This script creates an instance of the Python engine, sets the search paths to the persistent data path of the project, and then executes the "simple_game.py" script. The script also sets up the scope required for the game_loop function to execute correctly. Finally, the script uses a coroutine to execute the game_loop function.

In conclusion, Python for Unity is an incredible tool that allows developers to write scripts in Python within the Unity game engine. As we have seen, it is quite simple to set up Python for Unity and start writing Python scripts that interact with the Unity API and manipulate objects within the scene. Python for Unity provides new possibilities for developers who are looking to create complex game logic and features within Unity.

Popular questions

Sure, I can provide 5 questions and answers about "Python for Unity with Code Examples":

  1. What is Python for Unity?
    Answer: Python for Unity is a package that allows developers to use Python scripting in the Unity game engine. It provides the ability to create complex features and logic that would otherwise be challenging or time-consuming to implement in C#.

  2. How do you set up Python for Unity?
    Answer: You need to download and install the Python interpreter, and then install the Python for Unity package through the Package Manager in Unity. Once you have both installed, you can use Python in Unity.

  3. How do you create a Python script in Unity?
    Answer: To create a Python script in Unity, you need to create a new C# script and rename it with a .py extension. Once renamed, Unity will recognize it as a Python script.

  4. Can you access Unity's API from Python?
    Answer: Yes, you can access Unity's API from Python. You need to add references to the required namespaces in a C# script

Tag

PyUnity

I am a driven and diligent DevOps Engineer with demonstrated proficiency in automation and deployment tools, including Jenkins, Docker, Kubernetes, and Ansible. With over 2 years of experience in DevOps and Platform engineering, I specialize in Cloud computing and building infrastructures for Big-Data/Data-Analytics solutions and Cloud Migrations. I am eager to utilize my technical expertise and interpersonal skills in a demanding role and work environment. Additionally, I firmly believe that knowledge is an endless pursuit.
Website https://www.linkedin.com/in/ahmed-zakaria-20184a146/
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