Paint.NET TEX Plugin

Load and save League of Legends .tex texture files in Paint.NET

Features

• Load and save DXT1, DXT5, BC5, BC7, and BGRA8 texture formats.
• Auto detects the compression, mipmaps, alpha and saves accordingly.
• Second saving option with a menu to manually pick the compression, error diffusion dithering and mipmap generation.
• Fast DXT compression/decompression using native C#.
• Fast GPU-accelerated BC7 saving.
• Great error diffusion dithering quality.
• Full alpha channel support.

Requirements

• Latest Paint.NET version (.NET 9)
• .NET 9.0 SDK (for building)
• Windows 10 or later

Installation

Installer

1. Close Paint.NET
2. Run TexFileTypeSetup.exe from the releases
3. Go through the installation. The installer finds your Paint.NET FileTypes folder automatically. You can change the destination if needed.
4. Start Paint.NET

Manual

1. Close Paint.NET
2. Open C:\Program Files\Paint.NET\FileTypes
3. Paste both TexFileType.dll and Bc7Native.dll from the releases zip into this folder
4. Start Paint.NET

• Portable version note! In order to install the plugin on the portable version of Paint.NET please paste both dll files into [Paint.NET folder]\FileTypes
• Keep both dll files together. Bc7Native.dll is what makes BC7 saving fast. Without it BC7 still works but saves very slow.

Usage

Opening TEX Files

• File → Open → Select your .tex file
• Drag and drop .tex files into Paint.NET

Saving TEX Files

1. File → Save As
2. Choose "League of Legends TEX" from the file type dropdown

Saving TEX Files with customizable settings

1. File → Save As
2. Choose League of Legends TEX (with options) from the file type dropdown

Compression formats

Not sure which one to pick? Here's a quick rundown:

• DXT1 / BC1 — smallest file size. No alpha channel. Use for opaque textures where you want the file to be as small as possible.
• DXT5 / BC3 — twice the size of DXT1. Has full alpha. The classic choice for anything with transparency.
• BC7 — same size as DXT5 but way higher quality, works on champions. This is what Riot uses for most newer UI atlases.
• BC5 — two channels only (red and green). Used for normal maps. Same size as DXT5.
• BGRA8/Uncompressed — no compression at all, perfect quality. Takes 4× more space than DXT5. Use only when you need lossless quality and don't care about file size.

Other options

• Error Diffusion Dithering (DXT1/DXT5 only) — spreads out color quantization errors across nearby pixels using Floyd-Steinberg. Helps a lot on smooth gradients where DXT compression normally shows visible banding. Turn it on unless you have a reason not to.
• Error Metric (DXT1/DXT5 only):
  • Perceptual — weights the green channel higher since your eyes are more sensitive to green. Better for normal photo-like textures. Default.
  • Uniform — treats R, G and B equally. Better for non-color data like normal maps or masks where you don't want green to be favored.
• Generate MipMaps — saves smaller pre-resized copies of the texture alongside the main one making it 33% bigger. League engine scales .tex files on it's own if mipmaps are missing, enable only if you have a reason to.

Troubleshooting

Paint.NET crashes or the file doesn't load

• Make sure you're running the latest version of Paint.NET

Plugin doesn't appear in Paint.NET:

• Make sure you're running the latest version of Paint.NET
• Make sure Paint.NET is completely closed
• Check the FileTypes folder exists: C:\Program Files\Paint.NET
• Verify both TexFileType.dll and Bc7Native.dll are in the FileTypes folder

BC7 saving is slow:

• Make sure Bc7Native.dll is in the FileTypes folder next to TexFileType.dll

"There was an error while saving the file." error when saving:

• Make sure that the dimensions of the file are divisible by 4. This is a requirement for it to work in League.

Credits

Uses LtMAO's tex reading logic. Thanks to Tarngaina.

• GitHub: https://github.com/tarngaina/LtMAO

Compression and Error Diffusion Dithering Logic

• BC1/BC3/BC5/BC7 compression and decompression is based on Microsoft DirectXTex (MIT License).