04-02-2017, 08:55 PM
Thanks for the info, Bomb Bloke. 
It doesn't look like I could edited any particular section of an ETC1 texture in a hex editor, but the hope is to be able to completely replace them.
Since that last post, I got a texture compression tool from ARM and made some samples to look at. The byte structure strongly resembles what I'm seeing in the textures embedded in the model files, but those textures are lacking headers.
I also tried comparing the original model file to several with modified textures to see which parts had changed, and I found the big-endian values for the width/height of the four largest textures (128x256) near the start of where each of those textures is stored, but I'm not sure yet if that's just coincidence, since I couldn't find the width/height values for the smaller mip-levels. Not sure if they even have headers; that specification is slightly over my head.
If you're interested, I uploaded the standard Link model (shown in OP) here.
It doesn't look like I could edited any particular section of an ETC1 texture in a hex editor, but the hope is to be able to completely replace them.Since that last post, I got a texture compression tool from ARM and made some samples to look at. The byte structure strongly resembles what I'm seeing in the textures embedded in the model files, but those textures are lacking headers.
I also tried comparing the original model file to several with modified textures to see which parts had changed, and I found the big-endian values for the width/height of the four largest textures (128x256) near the start of where each of those textures is stored, but I'm not sure yet if that's just coincidence, since I couldn't find the width/height values for the smaller mip-levels. Not sure if they even have headers; that specification is slightly over my head.
If you're interested, I uploaded the standard Link model (shown in OP) here.