EditorImportPlugin in Godot – Complete Guide

Welcome to our latest tutorial where we delve into the fascinating world of Godot 4 and its powerful feature, the EditorImportPlugin class. If you’ve been eager to flex your coding muscles and create truly custom content within the Godot Editor, you’re in the right place. Whether you’re just starting out or already have some experience in game development, understanding EditorImportPlugins can elevate your game creation workflow to new heights. Stay tuned as we uncover this feature’s potential and show you how to tap into it by creating custom resource importers for your projects.

What is EditorImportPlugin?

The EditorImportPlugin is a special class in Godot’s game engine that allows developers to extend the editor’s resource importing capabilities. Essentially, it enables you to write your own importers for various file types, making it easier to integrate new asset types and tailor the import process to specific needs. This can be a game-changer for game developers who rely on unique file formats or require more control over how assets are brought into the Godot environment.

What is it for?

Imagine you’re working with a bespoke asset format, or you want to optimize how your assets are imported for better performance or usability within Godot. That’s where EditorImportPlugin comes in handy. Godot provides a set of built-in importers for common file types, but sometimes they might not fit your exact requirements. In such cases, you can create custom import logic to import files just the way your game needs them, whether that means handling custom 3D formats, importing procedurally generated textures, or something else entirely.

Why should I learn it?

Learning to use the EditorImportPlugin feature not only enables you to enhance your Godot Editor’s capabilities, but it also opens up a new layer of customization for your game development process. By mastering this tool, you can ensure that your game assets are optimized, maintain control over your import workflow, and ultimately create a more efficient and personalized game development experience. So let’s embark on this journey and unlock the full potential of your Godot assets together!

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Setting Up Your First EditorImportPlugin

To start working with EditorImportPlugin, you need to create a new script that extends ‘EditorImportPlugin’. Let’s create a simple script that will serve as the baseline for your custom importer.

extends EditorImportPlugin

func get_importer_name():
    return "my.custom.importer"

func get_visible_name():
    return "My Custom Format"

func get_recognized_extensions():
    return ["myext"]

func get_save_extension():
    return "res"

func get_resource_type():
    return "Resource"

func get_preset_count():
    return 1

func get_preset_name(i):
    return "Default"

In the script above, several functions are overridden to define the basics of our custom importer, such as the importer name, the file extension it recognizes, and the type of resource it generates.

Implementing The Import Method

The heart of the EditorImportPlugin is the ‘import’ method which gets called when a file with the recognized extension is being imported. Let’s add some logic to our plugin to handle the import process:

func import(source_file, save_path, options, r_platform_variants, r_gen_files):
    var file = File.new()
    if file.open(source_file, File.READ) != OK:
        return ERR_CANT_OPEN
    
    var content = file.get_as_text()
    file.close()
    
    var resource = Resource.new()
    resource.set_script(preload("res://path_to_your_custom_resource.gd"))
    resource.set_name("Custom Resource from " + source_file)
    
    if ResourceSaver.save(save_path + ".res", resource) != OK:
        return ERR_CANT_SAVE
    
    return OK

This is a basic import method that reads text from a file and creates a new resource with that text. It then saves this resource in the .res format which is the serialized resource format for Godot.

Handling Import Options

Import options are user-defined settings that allow for a more flexible import process. Overriding `get_import_options` will enable you to define your own options. Here’s how:

func get_import_options():
    return [
        {
            "option_name": "import_as_lossy",
            "default_value": false,
            "property_hint": PROPERTY_HINT_BOOL,
        }
    ]

func import(source_file, save_path, options, r_platform_variants, r_gen_files):
    var lossy = options["import_as_lossy"]
    # Your import logic here, taking into account the 'lossy' flag

With the code above, we’ve added a boolean option to our importer that can be toggled in the import settings within the Godot Editor. This option can then be used to adjust the import logic as needed.

Customizing The Importer’s User Interface

To make your EditorImportPlugin even more powerful, you might want to add a custom user interface for adjusting the import options. This requires using Godot’s UI nodes within the editor. To do this, you’ll need to override `get_option_visibility`:

func get_option_visibility(option_name, options):
    return true # For now, we want all options to be visible.

This function determines whether each import option should be shown in the custom user interface. As shown, we’re keeping it simple by returning true, which will show all available options.

By understanding these fundamental elements, you’re now equipped to create basic EditorImportPlugins in Godot 4. In the following section, we’ll build upon this knowledge by expanding our examples to include more advanced scenarios and functionalities.

As you become more familiar with the basic setup of EditorImportPlugin, it’s time to enrich our custom importer with more sophisticated features. These will allow you to handle different types of data and give you greater control over the import process.

Let’s dive into some more complex examples and explore the full capabilities of EditorImportPlugin:

Advanced Parsing and Resource Creation

Assume you are working with complex data such as JSON. You’re not just importing plain text; you’re importing structured data that requires parsing and turning into a consumable resource for Godot:

var json = JSON.parse(content)
if json.error != OK:
    push_error("Invalid JSON file")
    return ERR_PARSE_ERROR

var data_dict = json.result
var custom_resource = preload("res://path_to_custom_resource_script.gd").new()
custom_resource.import_data(data_dict)

if ResourceSaver.save(save_path + ".res", custom_resource) != OK:
    push_error("Failed to save resource")
    return ERR_CANT_SAVE

return OK

Here, the `import_data` method would be a custom function defined within your custom resource script that handles the data population from the JSON object.

Importing with Dependencies

Sometimes assets are not standalone and may reference other files or resources. In such cases, handling these dependencies is critical:

for dependency_path in custom_resource.get_dependencies():
    r_gen_files.append(dependency_path)

# ...rest of your import logic

By adding the paths of the dependencies to `r_gen_files`, you inform Godot about them, ensuring all necessary files are imported and available.

Multiple Resource Generation

There might be situations where a single file leads to the creation of multiple resources. This is how you can handle that:

var generated_resources = custom_resource.generate_multiple_resources()
for res in generated_resources:
    var res_save_path = save_path + "_" + res.get_name() + ".res"
    if ResourceSaver.save(res_save_path, res) != OK:
        push_error("Failed to save resource " + res.get_name())
        return ERR_CANT_SAVE
    
    r_gen_files.append(res_save_path)

return OK

In the code snippet above, `generate_multiple_resources` would be a custom function within your resource script that returns an array of resources that should be saved alongside the main one.

Handling Post-Import Operations

After a resource is imported successfully, you may need to perform some cleanup or setup operations. You can do this within the `import` method after saving your resource:

# After saving your resource successfully
custom_resource.perform_post_import_operations()

This could include anything from deleting temporary files to configuring project settings based on the imported resource.

Debugging

When things don’t go as expected in your import process, Godot’s debugger and output console are essential tools. To add custom debug information to your plugin, use the `print` and `push_error` functions:

print("Importing resource: " + source_file)
# ... the rest of your import logic
if some_error_condition:
    push_error("Custom error message specific to the issue encountered")
    return ERR_CUSTOM

By now, you should have a greater insight into the potential of Godot’s EditorImportPlugin. Experimenting with various scenarios and fine-tuning the importer to your requirements will enable you to integrate diverse asset types and control the import process to a greater extent.

As always, at Zenva, we believe in hands-on learning. We encourage you to take these code snippets and modify them for your project needs. Remember that each game and its assets are unique, so tailoring the EditorImportPlugin to handle your assets effectively can be a significant optimization for your project’s workflow. Happy coding!

Further enhancing our importer means implementing features like error handling, custom importer UI components, optimizing import settings for different scenarios, and including support for threading which can be vital for handling large or complex import tasks. Below are examples to guide you through these advancements.

Here’s how you can add more robust error handling in your ‘import’ method:

func import(source_file, save_path, options, r_platform_variants, r_gen_files):
    var error = perform_custom_import_logic(source_file, save_path)
    if error != OK:
        return error  # We propagate the custom error to Godot's import system.
    return OK

func perform_custom_import_logic(source_file, save_path):
    # Custom import logic here.
    # Return ERR_FILE_CORRUPT if the file is not as expected
    # Return ERR_FILE_MISSING_DEPENDENCIES if dependencies are missing
    # Use your custom error codes or Godot's predefined ones
    return OK  # or an appropriate error code

To create a custom importer UI component, you might introduce a user interface using Godot’s UI nodes:

func get_editor():
    var custom_importer_ui = preload("res://CustomImporterUI.tscn").instance()
    return custom_importer_ui

# Assuming 'CustomImporterUI.tscn' is a scene with a script attached handling UI logic

This custom UI can be designed to allow the user to set import options that are then used during the import process.

If you need different import settings based on whether the game is running on a PC or a mobile device, you can use `r_platform_variants` to handle this:

func import(source_file, save_path, options, r_platform_variants, r_gen_files):
    var resource = create_resource_from_file(source_file)
    
    for platform in r_platform_variants:
        if platform == "Android" or platform == "iOS":
            optimize_for_mobile(resource)
            
    save_resource(resource, save_path)
    return OK

func optimize_for_mobile(resource):
    # Optimize the resource specifically for mobile platforms.

In this scenario, `optimize_for_mobile` would be a function that tweaks the asset’s properties to perform better on mobile devices.

For handling large or time-consuming imports, Godot’s threading can be utilized:

func import(source_file, save_path, options, r_platform_variants, r_gen_files):
    var thread = Thread.new()
    thread.start(self, "_threaded_import", [source_file, save_path, options])
    return OK

func _threaded_import(data):
    var source_file = data[0]
    var save_path = data[1]
    var options = data[2]
    # Perform resource creation and saving operations in the thread.

User feedback during import operations is also essential, especially during lengthy processes. Implement a progress bar within your importer UI:

var progress_bar = get_node("CustomImporterUI/ProgressBar")
progress_bar.max_value = total_steps
progress_bar.value = 0

for step in range(total_steps):
    do_import_step(step)
    progress_bar.value += 1
    OS.delay_msec(50)  # Add a slight delay so the progress bar updates can be seen

Lastly, when your importer is finished, it is crucial to give feedback to the user. For example, display a message once the import is completed:

func import(source_file, save_path, options, r_platform_variants, r_gen_files):
    # After successful import
    show_import_result("Import successful!", save_path)

func show_import_result(message, path):
    var dialog = get_node("CustomImporterUI/ImportResultDialog")
    dialog.title = message
    dialog.popup_centered()

By integrating these code examples into your EditorImportPlugin, you can greatly enhance its functionality and usability. Keep in mind that error messages and progress reporting are not only helpful but also add a layer of professionalism to your tools.

At Zenva, we’re passionate about ensuring that you gain practical skills that can be immediately applied to your projects. Try cut and try these examples to see which combinations best fit the needs of your game and its assets. Personalize your Godot Editor and improve your game development pipeline with powerful import plugins. And above all, enjoy the creative process!

Continuing Your Game Development Journey with Godot

Your adventure into customizing Godot doesn’t have to stop here. If you’ve found your passion ignited by the power of EditorImportPlugin, it’s time to deepen your skills and expand your knowledge in game development with Godot. Our Godot Game Development Mini-Degree provides a comprehensive curriculum that will take you through the essentials of building games with Godot 4.

With our project-based learning approach, you’ll grasp complex concepts by building real-world projects from scratch. From mastering 2D and 3D game mechanics to scripting and UI systems, our courses are designed for both budding developers and those looking to refine their existing skills. And because we understand the fast-paced nature of technology, we ensure our content is up-to-date, revising courses whenever necessary to reflect the latest in game development practices.

Feeling ready for more? Explore the full array of our Godot tutorials and courses at Zenva, where we offer a wide-ranging selection for all experience levels. Check out our Godot courses today and continue your journey toward becoming a proficient game developer. At Zenva, we’re excited to be part of your journey and look forward to helping you achieve your game development dreams.

Conclusion

Embarking on the journey of creating custom EditorImportPlugins in Godot can open the doors to personalized game development and offer a tailored experience that caters to your project’s unique needs. Embrace the power and flexibility of Godot 4 and take your game assets to the next level with optimizations and enhancements that only custom tools can provide. Remember, the games you envision are not just dreams; they can be your reality with the right tools and knowledge at your disposal.

Whether you’re looking to refine your current skills or start from the basics, our Godot Game Development Mini-Degree is here to guide you every step of the way. Your game development adventure doesn’t stop with this tutorial—it’s just the beginning. Join us at Zenva, where we’re committed to providing you with high-quality content that propels you forward in creating unforgettable gaming experiences. Let’s build something extraordinary together!

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