Fungus can't grow on Trenches. I'd like Trenches to be able to exist next to land, so they can act as a barrier against fungus, just like Ridges are on land.
For that reason I tried to modify the shelf terrain textures, giving them the trench colour. The results are... bad. The coastal sand textures, necessary for terrain to look well next to land, also shows up between shelf and trench. Screenie at the bottom as illustration.
Terrain graphic generation seems to be determined by a terrain's layer order. In vanilla, land has the lowest layer order, thus are generated first. Then coast gets added on top of it, creating the coastal sand look. Then ocean gets added on top of it. Because that comes last, there is no coastal sands in the water. Unfortunately this means it's impossible to have more than one coastal terrain type.
As a consequence I was thinking to turn Trenches into a Feature. They would then require nif files though. I'm not sure if this is possible, or if I have the best idea on implementation. I'm wondering, is it possible to create nif files which are a flat coloured plane, and only of minimal height (Z-axis?), so that they would cover up the terrain textures, but still look completey flat??
One nif for all trenches would look bad though. There would be a sudden colour transition etc. I'm wondering if something like the icepack nifs is a possibility? The icepack XML can be copied for trenches. That would create some variety in trench connections, and there wouldn't be a straight line seperating trench from ocean. The dds could be the trench colour that appears in the game, including at the side of the dds some colour transition from the trench to ocean colours. Can an in-game screenshot be used to create dds textures for a nif??