본문으로 건너뛰기
CHOI HONGSU
⏱ 1 min read

Pack Textures To Array Tool

 

A Unity editor tool that takes multiple selected Texture2Ds and, with one right-click, auto-generates a grid PNG for Texture2DArray — including optimal grid calculation and automatic sRGB preservation. Category: Tool | Slug: pack-textures-to-array

Problem

To build a Texture2DArray, textures need to be composited into a grid PNG manually, and Texture Shape / Columns / Rows have to be set in the Inspector by hand. As the number of textures grows, the work becomes repetitive, and mistakes like forgetting the sRGB setting are easy to make.

Implementation

  1. 01

    1. Validation (fail-fast)

    Before merging, three conditions are checked together. If any one fails, abort immediately.

    CheckReason
    Same resolutionTexture2DArray requires all slices to be the same size
    Same sRGB settingPrevents mixing color spaces across slices
    Same folderDetermines output path + prevents accidental asset mixing
  2. 02

    2. Auto-compute the optimal grid layout

    Exhaustive search for the columns×rows arrangement that fits N items. Priorities:

    Examples: 5 items → 3×2 (waste 1), 7 → 4×2 (waste 1), 9 → 3×3 (waste 0)

  3. 03

    3. Pixel compositing via RenderTexture

    Each slice is copied into the final texture via Graphics.Blit → RenderTexture → ReadPixels.

    Watch-outs:

    • ReadPixels uses a bottom-left origin → flip Y so slice 0 is on top
    • Empty slots are cleared transparent (clearColor = 0,0,0,0)
    • GPU memory managed via RenderTexture.GetTemporary/ReleaseTemporary
  4. 04

    4. sRGB single-import preservation (AssetPostprocessor bridge)

    To apply the sRGB setting on the generated PNG in a single ImportAsset, a PendingSRGBSettings dict is used as a bridge.

    Applies sRGB on the first import without a second SaveAndReimport() call, avoiding the double-reimport problem.

  5. 05

    5. GPU limit pre-check

    Pre-validate that the output size doesn't exceed the GPU's maximum resolution via SystemInfo.maxTextureSize.

Conclusion

  • In the Project window, select 2+ Texture2Ds → right-click (COS) Pack Textures To Array once
  • T_{name}_Array.png is created, with Inspector guidance logged automatically

Tradeoffs & Future Work

Tradeoffs

  • Output is fixed to PNG (RGBA32) — if the source was a compressed format, compression settings must be applied separately after import
  • Converting the grid PNG into a Texture2DArray via Inspector (Shape / Columns / Rows) is still manual
  • Textures in different folders cannot be processed together (intentional restriction — prevents misordering)