Unity editor resource import processing function OnPostprocessTexture: in-depth analysis and practical cases

Unity editor resource import processing function OnPostprocessTexture usage

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Introduction

In Unity, we can use the editor resource import processing function ( OnPostprocessTexture) to customize the import process of texture resources. This function is inherited from the class AssetPostprocessor. By rewriting this function, we can perform some customized operations after the texture resource is imported.

Inherit AssetPostprocessor

First, we need to create a AssetPostprocessorscript that inherits from. This script will be used to handle the import process of texture resources. Here is a sample code:

using UnityEditor;
using UnityEngine;

public class TexturePostprocessor : AssetPostprocessor
{
    void OnPostprocessTexture(Texture2D texture)
    {
        // 在这里编写自定义的纹理导入处理逻辑
    }
}

In this example, we created a TexturePostprocessorscript called and overridden OnPostprocessTexturethe function.

Custom texture import processing logic

In OnPostprocessTexturethe function, we can write custom texture import processing logic. Here are five sample codes showing different uses:

1. Set the texture type to Sprite

void OnPostprocessTexture(Texture2D texture)
{
    TextureImporter textureImporter = (TextureImporter)assetImporter;
    textureImporter.textureType = TextureImporterType.Sprite;
}

In this example, we set the texture's type to Sprite. This way, when the texture is imported, it will automatically be set to the Sprite type.

2. Set the PackageTag name of the texture

void OnPostprocessTexture(Texture2D texture)
{
    TextureImporter textureImporter = (TextureImporter)assetImporter;
    textureImporter.spritePackingTag = "MyPackage";
}

In this example, we set the texture's PackageTag name to "MyPackage". This way, when the texture is imported, it will automatically be added to the texture package named "MyPackage".

3. Set the MipMaps check of the texture

void OnPostprocessTexture(Texture2D texture)
{
    TextureImporter textureImporter = (TextureImporter)assetImporter;
    textureImporter.mipmapEnabled = true;
}

In this example, we set the texture's MipMaps checkbox to true. This way, when importing the texture, it will generate MipMaps to provide better rendering performance and quality.

4. Modify the texture import format

void OnPostprocessTexture(Texture2D texture)
{
    TextureImporter textureImporter = (TextureImporter)assetImporter;
    textureImporter.textureFormat = TextureImporterFormat.RGBA32;
}

In this example, we set the texture's import format to RGBA32. This way when importing the texture it will be stored in RGBA32 format.

5. Modify the texture import platform settings

void OnPostprocessTexture(Texture2D texture)
{
    TextureImporter textureImporter = (TextureImporter)assetImporter;
    textureImporter.SetPlatformTextureSettings("Android", 2048, TextureImporterFormat.ETC2_RGBA8);
}

In this example, we modify the texture import settings on the Android platform to a maximum size of 2048 and use the ETC2_RGBA8 format. This way, when the texture is imported, it will be imported with the specified settings on the Android platform.

6. Turn off Mipmaps generation for Sprite type textures

When we import Sprite type texture resources, Unity will generate Mipmaps for it by default, in order to provide better rendering effects at different distances and resolutions. However, in some cases, we may not need to use mipmaps, such as when textures are used for UI images. Here is a sample code that shows how to turn off the generation of mipmaps when importing a Sprite type texture:

using UnityEditor;
using UnityEngine;

public class TexturePostprocessor : AssetPostprocessor
{
    private void OnPostprocessTexture(Texture2D texture)
    {
        if (assetPath.Contains("Sprites"))
        {
            TextureImporter textureImporter = (TextureImporter)assetImporter;
            textureImporter.mipmapEnabled = false;
        }
    }
}

In the above code, we first determine whether the imported texture resource is located in the "Sprites" folder, then obtain the corresponding TextureImporterobject, and mipmapEnabledset its attribute to false, thereby turning off the generation of Mipmaps.

7. Set compression format and quality according to different platforms

In Unity, we can set the compression format and quality of textures according to different platforms to optimize game performance and reduce package size. Here's a sample code showing how to set the compression format and quality for different platforms when importing textures:

using UnityEditor;
using UnityEngine;

public class TexturePostprocessor : AssetPostprocessor
{
    private void OnPostprocessTexture(Texture2D texture)
    {
        TextureImporter textureImporter = (TextureImporter)assetImporter;

        if (textureImporter.assetPath.Contains("Textures"))
        {
            if (textureImporter.platformTextureSettings.Length > 0)
            {
                foreach (var platformSettings in textureImporter.platformTextureSettings)
                {
                    if (platformSettings.name == "Android")
                    {
                        platformSettings.format = TextureImporterFormat.ETC2_RGBA8;
                        platformSettings.compressionQuality = (int)TextureCompressionQuality.Normal;
                    }
                    else if (platformSettings.name == "iPhone")
                    {
                        platformSettings.format = TextureImporterFormat.PVRTC_RGBA4;
                        platformSettings.compressionQuality = (int)TextureCompressionQuality.Fast;
                    }
                }
            }
        }
    }
}

In the above code, we first obtain TextureImporterthe object of the imported texture, then traverse its platformTextureSettingsarray, and set the corresponding compression format and quality according to the platform name. In the sample code, we set the ETC2_RGBA8 format and Normal compression quality for the Android platform, and set the PVRTC_RGBA4 format and Fast compression quality for the iPhone platform.

Through the above sample code, we can customize the processing of imported texture resources according to our needs, turn off the generation of Mipmaps for Sprite type textures, and set different compression formats and qualities according to different platforms. These operations can help us optimize game performance and reduce package size.

Using the OnPostprocessTexture function

To use OnPostprocessTexturea function, simply place the script inherited from AssetPostprocessoranywhere in your project. When you import texture resources, Unity will automatically call OnPostprocessTexturethe function and execute the custom logic you wrote.

Please note that OnPostprocessTexturethe function will only be called after the imported texture resource is completed, not when the resource is updated or deleted.

Summarize

By using Unity's editor resource import processing function OnPostprocessTexture, we can execute custom processing logic after the texture resource import is completed. This allows us to better control and manage texture resources by modifying their properties and settings according to project needs.

I hope this article will help you understand and use OnPostprocessTexturefunctions!

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