Last time I discussed about Unity texture compression I've mentioned that using ETC1 + Alpha channel is the best format because it provides the best build size and memory footprint in most cases. However, Unity does not support split alpha channel for iOS. Recently I had sometime to revisit this and wrote a simple plugin to support split alpha channel on both Android and iOS devices. The plugin is called USplitAlpha.

Apparently, the split alpha mechanism is very straightforward so different team will have different workflows that suit them best. For reference, there are some other solutions on github:

• https://github.com/DragonBones/DragonBoneToUnity/blob/2609886dff00bb503c1795a01aeda7481e28cbd3/Assets/Demo/_Script/Editor/SplitAlpha.cs
• https://github.com/TalosGame/BetterFramework/blob/3eda3261ccc582041aa5e3eaced9089dd4440f75/Assets/Editor/Compression/TextureCompression.cs
• https://github.com/WakakaYixixi/Unity_extension/blob/c0ba7936f96e0da77a4138249275fc1d89cdebed/Assets/Utils/Editor/SplitAlpha.cs