FUEL RESHADED v5.1 (2024 Mar 26) addon

added rimshine to trees, ground, grass, tire tracks, vehicles, etc

• I had a version from The Dark Mod, but created a new version that uses a different fresnel function that concentrates light right around the edges of objects, and concentrates it along the "sunny trail". When combined with bloom, this adds a nice rim light overbright higlighting to objects helping them stand out a bit and add depth to scenes.
• made it individually on/off'able, and adjustable for trees, grass + ground (since they have to function in-unison), man-made objects
• basically, PBR BRDF creates a realistic lighting model that ensures the light energy hitting things is properly conserved (neither created nor destroyed.) But, then we add rimshine as "creating light energy out of thin air" to boost the lighting to look more dramatic on edges. It's the "artistic license" part of graphic design where, once you've got everything looking natural, you boost certain spots to make them pop and make the scene look cinematic
• trees and grass use an extra black-n-white mask to add extra shine to some bits
• this makes grass a tiny bit shinier on the top than the base which simulates light diffusing through grass tops
• on trees, this makes a few parts of branches and some leaves shine even more on the "sunny trail".
  to simulate light diffusing through leaves towards the camera. essentially giving trees more "body" and light/shadow depth. (basically poor man's subsurface scattering of light through semi-transparent stuff)

added "specular in shadow" to vehicles and trees again, but just them and just a bit

• I had this in, then ripped it out when it was creating unnatural "circular sun" spots in some places, like in shadows on mountain sides.
• But, adding it back to a few things helps some stuff look more natural
• The idea is that objects that sit above the ground catch more ambient / indirect light that's bouncing around into the shadows, through the air, and off other surfaces
• this simulates things lower to ground having more AO darkening (eg: the ground, the grass) while tall things (vehicles, trees) get a bit of shine left on them in shadows.
• Helps add depth to objects
• not doing it on very large man-made objects b/c they look unnaturally glowy, and not doing it on ground/water/grass since you'll see an unnatural sun spot in shadows

replaced post-processing color brightness w/ a better version that reduces math per-pixel for same result

• added user-value to adjust it. So, it's no longer an on/off, but you can increase/decrease it to your liking.

optimized some calc's more

• been looking at Ben Clowder's shader tuts
• While they're Unity & Unreal GUI focused, the basic math and concepts were able to apply to some things in the FUEL shaders. (Mainly optimizing the normal map calculations)
• highly recommend his series of vids

also used Ben's Rain Tutorial 14 "Wetness" vid to figure out how to oversaturate & darken color
realistically when it rains

• so things get a deeper color and a bit darker in rain
• this enhances rainy areas as they become darker, deeper, and wetter-looking
• (the desaturate function provided the added bonus of using it on post-processing color over-saturation as a cheaper "color brightness" function)

fixed sun/moon so clouds impact them again

• unfortunately, Moon is a bit purple'ish again, b/c it required adding an atmospheric haze value back in. But, clouds covering moon & sun like they should is more realistic.

Ambient Occlusion softening only impacts the AO created by trees, not under vehicles.

• This helps soften shadows in trees which were the main culprits of overly-dark shadows while letting vehicles still have their full AO under them to help add depth and positioning to them when in shadows under trees

Misc Commentary:

Odd part about working on shaders is you'll find industry-standardized functions and algorithms for some things, then other things are just an absolute hack-fest and experimentation. EG: PBR BRDF is pretty standard these days. But, implementing rain.. I thought I could come across a simple algorithm without having to implement some complex subsurface scattering thing. But, no. Ben's tutorial on "wetness" showed various hacks to darken things while over-saturating their colors as hack ways to make things look wetter, but it's not implementing a standardized white paper algorithm. It's funny how there's this technical, standardized base of industry algorithms that we then prop up 3 racoons in a trenchcoat on in hackish fashion to simulate other effects.

I tried giving VSM / ESM shadows another crack, but after checking over the code Asobo was trying to use the tex2Dproj and tex2D functions with shadow lookups and projection calculations. I already experimented trying to do that using their implementation of Cascading Shadow Maps (CSM), but couldn't get it to work. So, if VSM (Variance Shadow Maps) and ESM (Exponential Shadow Maps) rely on that, it simply won't work. I'm basically stuck with the limitations of the shader model, DirectX 9, and whatever the game engine pipes in. After a while it's like trying to beat your head into a wall trying to get things to work without having complete control over the things you'd ideally control to make it happen.

This leads me to "giving up" on working on the shaders again. I wanted to really make the shadows look nicer, do god rays, and also do screen space ambient occlusion. But, I think all that has to use game engine tweaks or better Direct X version or something I can't control. I decided to practice "mindfulness" with the shaders. IE: instead of trying to force certain things, I decided to just stroll through the shaders every now and then and see where things take me. Or, I'll play another game, see some effect, and wonder if I can implement it in the FUEL shaders. (EG: the Rimlighting / Rimshine effect I noticed when playing The Dark Mod). This takes a lot of pressure off, but it means I create a "white whale" effect where I'll be annoyed at not being able to Captain Ahab the main features I wanted to implement, b/c they'll be constantly out of reach.

Once again, I'm having to put the shaders away, b/c I'm spending to much time obsessing over things I can't change, and working on stuff that shouldn't change and risk breaking it while trying to do very minor things of little consequence.

It's a 14yo game. Time to let it go.