[TEC] Hull water film

[kapitan_zur_see]

update: SEE [REL] here:

http://www.subsim.com/radioroom/showthread.php?t=185834


Just another abandoned feature I stumbled upon while messing around with the goblin editor... I don't know if it has been previously mentioned, but I thought it might interest some moders here nevertheless.

If you load up any u-boat model and its sim files, there's a behavior you can attach to the hull that (tries to) simulate a water film. It can be find under the grannyloader behavior and it's called HullWaterFilm.

Now if you normally try to apply it, you'll get an error and a message stating that there's a missing texture called "perlin_noise_4channels" which goblin should be finding under the data/textures path... Now there's normally no textures directly there (they should be in either Tnormal or TLowRes subdir), and textures related to FX stuff should even be in the data/misc directory. Hardcoded mistake or oversight probably...

Scanned whole /data to search for it and it doesn't exist, but there's three called perlin_noise, perlinnoise and perlinnoise1 under data/misc. So I took one, copy it over to data/Textures and rename it accordingly. Then I could apply the effect in Goblin, though I don't know how different the texture I used is compared to what was to be that perlin_noise_4channels texture that is missing and what's the impact on the effect.

It renders the whole hull slightly darker, light is much less diffused and there's a strong specular highlight under direct light. Bump mapping is also strongly affected. This is to try mimicking some wetness.

Here are comparison shots in Goblin On and off, under exact same lightning condition:

Without:




With:






Here's what it looks ingame:










Moreover, there seems to be some special function that was more or so implemented to it that seems to be related to height (altitude of the sub) albeit you cannot see it most of the time when applied to the hull (the effect seems always higher than the hull top). Indeed, you can see it if you try to apply the effect on the conning tower (it doesn't really work and causes glitches ingame as it was obviously made only for the hull).

The effect is not just applied as a plain reflective texture, but there's some kind of "line" that seems related to height state of the sub ingame that divide the effect in two. Ingame the line will mimic the waves outline shape and everything that is bellow will be rendered with the special water film effect and everything above will be rendered as normal, without the effect. The outline also seems to go lower and move up again from time to time although it seems rather unrelated to height state of the sub.

Here's some conning tower shots, you'll clearly see what I means and the difference above and under the outline (you won't see wave shape mimic under Goblin however):






It is of interest to notice that sadly, there's strictly no controllers to fiddle with in this behavior such as min/max altitude (as in caustics effect) and the like.

Applying to hull ingame is stable, doing as well on conning tower does produces glitches after a small period of time (flickering of the whole sub textures, conning tower appearing transparent). If applied as is, the effect is always turned on, be it on surface or underwater. Haven't tried messing around with my perlin_noise_4channels improvised texture yet.

It is tied to the granny shader you can find under /shaders/Granny , however sadly, my shaders programming skills are next to zero...!

I think there might be a small playground there, if it never has been mentioned before.

I believe it's been clearly abandoned due to lack of time, the effect not looking good enough right out of the box and a decade function not being implemented properly (I believe the main purpose of this "line dividing stuff" was to gradually go lower just after surfacing the sub so as to mimic the film pouring and disappearing)

Still, I can release a WIP version as is (for the hull only and always on) for those who may still be interested in it at this state.