Creating TMP Font Assets After Build In Unity

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Creating TMP Font Assets After Build in Unity

Hey guys! So, you're looking to let your players customize their text in your Unity game, right? Specifically, you want to allow them to upload their own fonts and use them in those cool TextMeshPro (TMP) text fields. The big question is: Can you actually create a TMP Font Asset from a custom font after the game has been built? Let's dive into this and see how we can make it happen.

The Challenge: Dynamic Font Loading

Okay, so the core problem is this: you can't just slap a TTF file into your game after it's been built and expect it to work seamlessly with TMP. You need a TMP Font Asset, which is basically a pre-processed version of the font that TMP uses to render text. Think of it like a special instruction manual for your font.

When you import a font in the Unity editor, TMP handles the conversion to a Font Asset for you. But what if you need to do this at runtime, after the game has been compiled and distributed? That's where things get a bit more interesting, but don't worry, it's totally achievable!

This is a super common request, especially for games with a lot of user-generated content or those that prioritize accessibility. Imagine being able to support different languages with ease, or letting players choose a font that's easier for them to read. It opens up a whole new world of customization possibilities.

Why Not Just Use the TTF Directly?

You might be tempted to just use the TTF file directly, but TMP doesn't work that way. It needs that pre-processed Font Asset because it contains crucial information like the character glyphs (the visual representations of each character), their positioning data, and other optimizations that allow for efficient rendering. So, we're stuck with creating these Font Assets dynamically.

The Solution: Runtime Font Asset Creation

The good news is that TMP provides the tools and flexibility you need to create Font Assets at runtime. It's not a super simple process, but it's definitely doable. Here's a breakdown of the key steps and things to keep in mind:

1. Loading the Font File

The first thing you need to do is load the TTF font file. You can load it from a file path, a byte array, or even a stream. The most common approach is to let the user select a font file and then load it using File.ReadAllBytes() or similar methods. Make sure you handle file access permissions correctly!

Example:

using System.IO;
using UnityEngine;
using TMPro;

public class FontLoader : MonoBehaviour
{
    public TMP_FontAsset loadedFont;

    public void LoadFontFromFile(string filePath)
    {
        if (string.IsNullOrEmpty(filePath))
        {
            Debug.LogError("File path is empty!");
            return;
        }

        try
        {
            byte[] fontData = File.ReadAllBytes(filePath);
            loadedFont = CreateFontAsset(fontData);
            if (loadedFont != null)
            {
                Debug.Log("Font loaded successfully!");
            }
        }
        catch (Exception e)
        {
            Debug.LogError({{content}}quot;Error loading font: {e.Message}");
        }
    }

    private TMP_FontAsset CreateFontAsset(byte[] fontData)
    {
        if (fontData == null || fontData.Length == 0)
        {
            Debug.LogError("Font data is invalid!");
            return null;
        }

        // Create the font asset
        TMP_FontAsset fontAsset = new TMP_FontAsset();
        fontAsset.name = "CustomFont"; // Give it a name
        fontAsset.faceInfo = new TMP_FontAsset.FaceInfo();

        // Load the font using the byte array
        if (!fontAsset.LoadFace(fontData))
        {
            Debug.LogError("Failed to load font face.");
            return null;
        }

        // Optional: Set character set - This is very important. You'll need to know which characters your font supports.
        // If you don't set this correctly, you'll see empty squares instead of characters.
        // You can use the Character Set property to specify the range of characters.
        // For example, if you know the font only supports the basic Latin characters,
        // you can use TMP_FontUtilities.GetTextMeshProFontUnicodeRange() to get the range.
        // Then you'll need to specify which characters you want to include.

        // The process can be quite involved, needing things like font atlas size and other properties,
        // which affect the quality and performance of your text rendering.

        fontAsset.UpdateFontAsset(); // This is essential!  It builds the atlas.
        return fontAsset;
    }
}

Important Considerations:

  • File Permissions: Make sure your game has the necessary permissions to read files from the location where the user selects the font.
  • Error Handling: Always include robust error handling to gracefully handle cases where the font file is corrupted, the path is incorrect, or the file can't be accessed.

2. Creating the TMP Font Asset

This is the core of the process. You'll need to use the TMP API to create a new TMP_FontAsset. Here's a general outline:

  1. Create a TMP_FontAsset instance: This is where your new font asset will live.
  2. Load the font face: Use the LoadFace() method to load the font data from your byte array.
  3. Set Character Set: This is a crucial step. You'll need to specify the character set or ranges that your font supports. If you don't do this correctly, you'll see empty boxes instead of text for characters that aren't included in the character set. You might need to let the user select a character set or provide a way to customize it, depending on your game's needs. The character set dictates which glyphs are available in the font. Using the wrong character set will lead to missing characters. You might need to use techniques to determine the supported characters of a font.
  4. Update the font asset: Call UpdateFontAsset() to generate the font atlas and finalize the asset. This is where TMP actually creates the texture and other data needed for rendering.

3. Using the Font Asset

Once you have your TMP_FontAsset, you can assign it to your TextMeshPro text components. You can do this by:

  1. Accessing the TextMeshPro component: Get a reference to the TextMeshPro or TextMeshProUGUI component on your game object.
  2. Setting the font: Set the font property of the text component to your newly created TMP_FontAsset.

Advanced Techniques and Tips

Let's go a bit deeper, guys!

Caching and Optimization

Creating font assets at runtime can be resource-intensive, so you'll want to optimize this process. Here are a few tips:

  • Caching: Store the created TMP_FontAsset instances in a dictionary or other data structure so you don't have to recreate them every time. Check if you already have the font asset loaded before trying to create it again.
  • Font Asset Pre-creation: If you know the user is going to be loading fonts, you could pre-create a generic font asset with a basic character set (e.g., the ASCII set) to avoid a lag when the font is first loaded. Then, you can replace the glyphs in the pre-created asset with those from the custom font. This gives the user immediate text while the custom font is generated.
  • Asynchronous Loading: Load the font file and create the font asset in the background using async and await or coroutines to avoid blocking the main thread and freezing your game. Let the user know the font is being loaded with a progress bar.
  • Atlas Size: The font atlas is a texture that contains the glyphs for your font. Consider the atlas size. A larger atlas can hold more glyphs, but it also takes up more memory. Find the right balance between the number of glyphs your font needs to support and the performance of your game.

Character Sets and Unicode Ranges

Handling character sets and Unicode ranges is crucial for supporting different languages and character variations. Here's a more detailed look:

  • Character Set Selection: Give the user options to select the appropriate character set (e.g., Latin, Cyrillic, Greek, etc.).
  • Unicode Ranges: Use Unicode ranges to specify the characters to include in the font asset. TMP provides utilities like TMP_FontUtilities.GetUnicodeRangeList() to help you with this.
  • Font Fallback: Implement font fallback so that if a character is not found in the primary font, it will fall back to a default font that supports that character.

Font Quality and Rendering Options

  • Font Size and Style: Allow the user to adjust the font size, style (bold, italic, etc.), and other rendering options.
  • Font Asset Properties: Experiment with the font asset properties (e.g., sampling point size, padding) to fine-tune the rendering quality.

Code Example: Putting It All Together

Here's a more complete example that demonstrates the core principles of creating a TMP Font Asset at runtime. Remember to adapt it to your specific game's needs.

using System; // For Exception handling
using System.IO; // For file operations
using System.Threading.Tasks; // For async operations
using UnityEngine; // For Unity-specific functions
using TMPro; // For TextMeshPro-related components

public class DynamicFontLoader : MonoBehaviour
{
    public TMP_Text targetText; // Drag your TextMeshPro text component here in the Inspector
    public string filePath;
    public TMP_FontAsset loadedFontAsset; // Keep track of the loaded font asset

    // Method to load and apply a font from a file path
    public async void LoadAndApplyFont(string filePath)
    {
        if (string.IsNullOrEmpty(filePath))
        {
            Debug.LogError("File path is invalid.");
            return;
        }

        try
        {
            // 1. Load the font data from the file (using async to avoid blocking the main thread)
            byte[] fontData = await LoadFontDataAsync(filePath);
            if (fontData == null || fontData.Length == 0)
            {
                Debug.LogError("Failed to load font data.");
                return;
            }

            // 2. Create the TMP Font Asset
            TMP_FontAsset newFontAsset = await CreateTMPFontAssetAsync(fontData);

            if (newFontAsset != null)
            {
                // 3. Apply the font to the target text component
                ApplyFontToText(newFontAsset);
            }
            else
            {
                Debug.LogError("Failed to create font asset.");
            }
        }
        catch (Exception e)
        {
            Debug.LogError({{content}}quot;An error occurred: {e.Message}");
        }
    }

    // Asynchronously load font data from the given file path
    private async Task<byte[]> LoadFontDataAsync(string filePath)
    {
        return await Task.Run(() =>
        {
            try
            {
                return File.ReadAllBytes(filePath);
            }
            catch (Exception e)
            {
                Debug.LogError({{content}}quot;Error reading font file: {e.Message}");
                return null;
            }
        });
    }

    // Asynchronously create a TMP Font Asset from font data
    private async Task<TMP_FontAsset> CreateTMPFontAssetAsync(byte[] fontData)
    {
        return await Task.Run(() =>
        {
            if (fontData == null || fontData.Length == 0)
            {
                Debug.LogError("Invalid font data.");
                return null;
            }

            TMP_FontAsset fontAsset = new TMP_FontAsset();
            fontAsset.name = "CustomFontAsset";
            fontAsset.faceInfo = new TMP_FontAsset.FaceInfo(); // Needed for the font to load

            if (!fontAsset.LoadFace(fontData))
            {
                Debug.LogError("Failed to load font face.");
                return null;
            }

            fontAsset.UpdateFontAsset(); // Build the font atlas
            return fontAsset;
        });
    }

    // Applies the given font to the target text component
    private void ApplyFontToText(TMP_FontAsset fontAsset)
    {
        if (targetText != null && fontAsset != null)
        {
            targetText.font = fontAsset;
            Debug.Log("Font applied successfully!");
        }
        else
        {
            Debug.LogError("Target text component or font asset is null.");
        }
    }

    // This method is called from the UI, using a file browser for example.
    // Or you can hardcode the filePath, if the font comes from a remote location.
    public void LoadFontFromPath()
    {
        LoadAndApplyFont(filePath); // Or your way of getting the file path, for example, from a file browser
    }

}

How to use the code:

  1. Create a new C# script in your Unity project (e.g., DynamicFontLoader).
  2. Copy and paste the code into the script.
  3. Attach the script to a GameObject in your scene.
  4. Drag your TextMeshPro text component from the scene to the Target Text field in the Inspector.
  5. Provide the file path from which to load your custom fonts.
  6. Call the LoadFontFromPath() method when you want to load a font (usually through a UI button).

Conclusion

So, can you create a TMP Font Asset from a custom font after the game is built? Absolutely, yes! It takes a bit of work, but with the TMP API and the right approach, you can empower your players to customize their text with their favorite fonts. Remember to handle file loading, font asset creation, and character sets carefully. Good luck, and have fun building those awesome customizable text features!

I hope this helps, and happy coding, everyone!