TGA files are used for some of the graphics in NWN. It is a uncompressed format which means no quality loss but a huge amount of speed and huge files when the image dimensions are even moderately big.
It has the lowest priority of texture formats usually, outranked by PLT then DDS (ie filename.dds will load over filename.plt which loads over filename.tga) but if you have the same DDS and TGA file at the same "level" the TGA loads first - see Content Load Order for more information.
NWN supports 32bit TGA files with alpha. They must be powers of 2, such as 32x32 or 128x1024. They can be uncompressed or compressed with RLE compression (using Bottom Left, not sure about Top Left). GIMP for instance can output compressed RLE which is up to half the size for some icons/textures.
| Image Dimensions | Uncompressed TGA File Size | Notes |
|---|---|---|
| 32x32 | 4KB | Game's default (now awful) icon size (eg; feats, spells) |
| 64x64 | 16KB | |
| 128x128 | 64KB | |
| 256x256 | 256KB | Maximum limit of certain shiny water effects. Retaining TGA for this might be advisable to improve quality slightly. |
| 512x512 | 1MB | |
| 1024x1024 | 4MB | |
| 2048x2048 | 12MB |
The TGA file format was used by Bioware to retain quality and compatibility due to the very early introduction of DDS. Therefore it got used for a large portion of the original game files. Once Hordes of the Underdark came around most usual textures were made in DDS only.
Due to quirks with the game engine and toolset this is a list of suitable uses of TGA. See also Textures for a full use case breakdown between formats.
| Type of Image | NWNEE TGA Required/Preferred | Notes |
|---|---|---|
| Mouse Cursors | Required | NWN:EE needs replacement and custom mouse cursors to be in TGA format |
| Item Icons | Required | TGA is used to validate that icons exist clientside (loading the icon at all) and serverside (eg in CopyItem), even if DDS can load once it's validated. The toolset also extensively relies on TGA being present and only loads TGA files. It also gets confusing since sometimes it needs a TGA to be present even if a PLT file would usually load. Go figure! |
| Palette definition files | Required | The toolset uses these files so to match the game use TGA |
| Portraits | Required for chargen | For new portraits TGA seems to be required (but only one size is needed now). See portraits.2da |
| Feat and Spell Icons | Not required (but can be preferred) | There is no reason to use TGA but it can help retain quality (especially if using the 32x32 standard icon size not a higher resolution version!), the toolset doesn't load these icons and they're not validated so it's reasonably safe to use DDS. |
| GUI Icons | Not required | Should load DDS fine, but as per Feat and Spell icons at 32x32 it's worth using TGA for quality, and sometimes even for higher resolution versions to retain quality at the cost of load times. |
| NUI Styling Images | Needs testing | nui_skin data can point to new image files. Need to test if these need to be TGA or can now be DDS instead. |