I have 2 textures. I want to use one as a regular diffuse
texture on my object, and another texture in a
higher channel, using the #add blend function.
This works fine, except when my regular diffuse texture has
transparent areas (i.e. it uses an alpha
channel), in which case it becomes opaque when the #add
texture layer is applied in a higher channel.
Using the #multiply blend function seems to work fine over a
diffuse texture with an alpha channel, but
using the #add function appears to completely prevent the
diffuse texture below from appearing
transparent at all.
Update, which just makes it weirder, it seems the
transparency is preserved if the 3D renderer is set to #directX5_2
or #software. I guess this is something to do with the fact that
both of those modes only support one texture layer, so the 2nd
layer is drawn in a second renderer pass.