Basis compression of font png created from font asset

RyutoHaga · March 10, 2023, 5:58am

I used PlayCanvas to process all Japanese fonts. Textures of 4096x4096 were generated, with a file size of 10MB to 20MB.

The project can be found here:
https://playcanvas.com/editor/scene/1678016

The Japanese data can be found here:
https://gist.github.com/yushimatenjin/26b1a8a2223c09a2bd65341bec19fa6f

We tried to see if we could reduce the size when using Japanese:

1. Original

6.9MB + 6.8MB = 13.7MB

2. Basis-compressed( ETC / Default ) textures ( I downloaded the contents of Basis compression in the editor locally and replaced it. )

1.4MB + 1.4MB = 2.8MB

When the extension was Basis, the display was corrupted because one or more texture files were not used (not incremented).

github.com

playcanvas/engine/blob/5a22ee6e885d5f9f880214e7fb96711abd542b95/src/framework/handlers/font.js#L126

      
        
                        textures[index] = texture;
                        numLoaded++;
                        if (numLoaded === numTextures) {
                            callback(null, textures);
                        }
                    };
            
            
        if (index === 0) {
                        loader.load(url, 'texture', onLoaded);
                    } else {
                        loader.load(url.replace('.png', index + '.png'), 'texture', onLoaded);
                    }
                };
            
            
    for (let i = 0; i < numTextures; i++)
                    loadTexture(i);
            }
            
            
open(url, data, asset) {
                let font;
                if (data.textures) {

The result of rewriting this code locally to Basis is shown here.

3. I used an online compression service to compress png files.

https://compresspng.com/ja/
3.0MB + 2.9MB = 5.9MB

4. Resized from 4096 to 2048, then compressed png.

1.3MB + 1.2MB = 2.5MB

I was wondering if a font texture resized to 2048 pixels could be used in some cases. If possible, it would be nice to have an option to select the texture size in the editor, since the file size becomes very large when trying to handle Japanese textures, making it difficult to use on the Web.