Texture Packing and Shader Variant Stripping for Unity Mobile

TRIGGER

Use this skill when the user is dealing with texture optimization, channel packing, shader variant bloat, build size, shader compilation time, or shader keyword management in Unity. Triggers include: "channel packing", "texture packing", "mask map", "MODS map", "RMA", "shader variants", "variant stripping", "multi_compile", "shader_feature", "build size", "shader keywords", "Always Included Shaders", "IPreprocessShaders", or complaints about slow shader compilation or large build sizes.

TEXTURE CHANNEL PACKING

Channel packing stores multiple grayscale maps in a single RGBA texture. This reduces both texture sample count and memory bandwidth — the primary bottleneck on mobile.

Standard URP Packing Convention

Mask Map (single RGBA texture):
  R = Metallic
  G = Occlusion (AO)
  B = Detail mask (or custom)
  A = Smoothness