Packs six cube-face images into one 3×2 atlas Texture (px py pz / nx ny nz). Uses invertY:false so UV cellY=0 maps to the +faces row matching the shader.
Packs six cube-face images into one 3×2 atlas Texture (px py pz / nx ny nz). Uses invertY:false so UV cellY=0 maps to the +faces row matching the shader.