Texture Channel Splitter — Unpack RGBA / ORM into Grey Maps
A packed texture read through a browser canvas loses every byte under alpha 0. The Texture Lab decodes the PNG itself, so each channel comes out exactly as it was stored.
- Channel PNGsMeasured· numpy
- Normal mapMeasured· numpy
- Packed mask / ORMMeasured· Pillow
- Engine importUNVERIFIED
What it does
- One 8-bit grey PNG per channel (R, G, B, A), byte-identical to the source.
- RGB under fully transparent texels is kept (checked on 2048 texels).
- Each channel previewed with its meaning in the chosen engine layout (Unity HDRP, URP, ORM).
- Invert a channel (e.g. roughness ↔ smoothness) and save the result.
How to do it
- Drop the packed PNG.
- Pick the engine layout to see what each channel means.
- Invert a channel if needed.
- Download the channel PNGs.
Outputs and how each was checked
"Measured" means the downloaded file was opened again outside the page (Pillow, numpy or an independent parser) and the property was measured. Loading these files in a game engine was not tested.
| Target | Files | Check |
|---|---|---|
| Channel PNGs | <name>-r/g/b/a.png (8-bit grey) | Measured numpyByte-identical per channel, including RGB under fully transparent texels. |
| Normal map | PNG · OpenGL (+Y) or DirectX (−Y) | Measured numpyDecoded vectors are unit length (worst deviation 0.0002); OpenGL and DirectX differ in green only. |
| Packed mask / ORM | Unity HDRP mask · URP metallic · ORM (glTF, Godot) | Measured PillowPacked bytes checked: ORM preset over AO 10 / roughness 80 / metallic 220 → (10, 80, 220, 255). |
| Engine import | Unity · Unreal · Godot | UNVERIFIEDNot imported in any engine. |
Evidence
Channel unpack byte-identical on all four channels (max difference 0), 2048 transparent texels keep their RGB; edge bleed changed 448 texels, all with alpha 0, and no alpha byte; OpenGL ↔ DirectX differ exactly in green (255 − g); converted normals decode to unit vectors.
Limits
- Exact channel bytes need PNG; JPEG/WebP are decoded by the browser and marked "not byte-exact".
- Interlaced PNG and 16-bit output are not supported; up to 33.5 million pixels on the exact path.
- A normal map's convention cannot be detected from its pixels, only converted.
- Nothing was imported into Unity, Unreal or Godot: channel orders rest on their documentation and engine source.
Questions
Why not just open it in an image editor?
Many editors and every browser canvas premultiply alpha, so metallic/roughness bytes under transparent texels come back as 0. This path reads the PNG bytes directly.
Does it work with JPEG?
Yes, but JPEG is decoded by the browser and marked "not byte-exact".
Is it free, and do I need an account?
Everything on these pages is free and works without an account. There is no watermark and no export that is held back.
Are my sprites uploaded?
No. The Studio decodes, packs and exports in this browser tab. Projects are autosaved in the browser (IndexedDB) and can be saved as a .nerulio file.
Does it need Aseprite or an engine plugin installed?
No. .aseprite files are read and written in the browser, and each engine bundle carries what that engine needs (for Godot, the import settings and scene; for Unity and the Godot TileSet, a small editor script).