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These are the types for OpenGL ES 3.0 with notes:
| File Specification | Definition | NWN EE Notes |
|---|---|---|
| GL_COMPRESSED_R11_EAC | 11 bits for a single channel. Useful for single channel data where higher than 8 bit precision is needed. For example, heightmaps. | |
| GL_COMPRESSED_SIGNED_R11_EAC | Signed version of GL_COMPRESSED_SIGNED_R11_EAC, useful when signed data is needed. | |
| GL_COMPRESSED_RG11_EAC | 11 bits for two channels. Useful for two channel data where higher than 8 bit precision is needed. For example, normalised bump maps, the third component can be reconstructed from the other two components. | |
| GL_COMPRESSED_SIGNED_RG11_EAC | Signed version of GL_COMPRESSED_RG11_EAC, useful when signed data is needed. | |
| GL_COMPRESSED_RGB8_ETC2 | 8 bits for three channels. Useful for normal textures without alpha values | This is the standard non-alpha texture format NWNEE reads |
| GL_COMPRESSED_SRGB8_ETC2 | sRGB version of GL_COMPRESSED_RGB8_ETC2 | |
| GL_COMPRESSED_RGBA8_ETC2_EAC | 8 bits for four channels. Useful for normal textures with varying alpha values | This is the alpha texture format NWNEE reads The game defaults to 0.5 alpha mean values for KTX textures. |
| GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC | sRGB version of GL_COMPRESSED_RGBA8_ETC2_EAC | |
| GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2 | 8 bits for three channels and a 1 bit alpha channel. Useful for normal textures with binary alpha values | Punchthrough is not supported explicitly. |
| GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2 | sRGB version of GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2. | Punchthrough is not supported explicitly. |
KTX Issues
Due to the above notes the specular and roughness maps don't appear to load in the PC version correctly (being all black/incorrect) whatever combination of KTX ETC2 version is used at least from my testing.
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