IBL in AI War 2!

Pics lower down. 🙂

The Problem I Wanted To Solve

One of the frustrations I’ve had with the ship graphics in AI War 2 is that it’s hard to make sure that they’re both vibrant AND nicely reactive to the environmental colors and similar while being so hugely restricted in terms of how many truly-PBR techniques we can use because of limitations caused by having SO many realtime objects to light in that sort of scenario.

I’ve gotten around that with a variety of tricks that have evolved over the last months, and it’s been working well with Blue’s cel-shaded clean ship albedo/diffuse coloring.  It wasn’t perfect, but I knew I’d have time to improve it later — the main issue I had was that specular highlights tended to trend to white on all models.

Part of the recent evolution in the look of ships was to give them more of a metallic-on-cel-shaded look, which allows for a lot more flexibility in the sort of visual effects we can then do.  My first approach to that was to think of PBR, and so that’s what we recently converted to — the Unity Standard shader, which is heavily PBR.

There were a variety of challenges with that, though — I couldn’t control the amount of specular whiteout as much as I wanted while still having a ton of metallic feel to it.  Cinth kind of set me on the path of chasing the metallic look to marry that to the cel-shaded look that Blue sent me chasing, and I really wanted to get those working together.

The New Approach!

Experimenting a bunch last night and then today, I’ve settled on an IBL approach that is using Blinn-Phong again, back to what my custom rim-lighting shader was doing before we went to the standard shader (sorry, no link on that one — it’s somewhere on the forums or kickstarter, though).

Anyhow, the big benefit of this approach is that I’m able to handle reflections via a cubemap that has nothing to do with the larger scene, and then tint the reflections as needed, along with using a fresnel effect on them.  Then beyond that I’m faking a metalness map in some cases (such as for the fighter and bomber) by additively using the inverse of that data in the diffuse channel.

It’s All About The Motion

Bear in mind that the result is a lot more dramatic in motion, because as ships move around you get a lot more of them shimmering and glinting in the light as a school of fish might.

Even so — in still screenshots I think that it looks a bit better now.  But in motion it’s night and day.

Also: Lighting

Also!  Bear in mind that based on the lighting of the planet in question, you’ll get pretty drastically different results from what I am about to show.  In one case I was frustrated because the serial number on the fighter wasn’t showing up properly… only to realize that in fact it was acting appropriately in the lower-direct-lighting environment it was in at the time.

The basic rule of thumb is that the ships wind up varying in appearance more from planet to planet in terms of the characteristics of light on them, which is a big part of the goal.

Bomber

The above is what I had before, using the Standard shader and a metalness map.  I was particularly unhappy with that one.

Now a few shots of what the new one looks like from various angles:

You’ll notice that in the two different angles give a really different feel to the color, even within one lighting profile.  That has a lot to do with the fresnel effect and cubemap for the reflections, but also just the specular highlights based on the view angle toward the light, too.

In a couple of angles that makes it looked a little more washed out in the cool orange parts, but very metallic — and then in other angles it looks rich and deep like the original cel-shading work that Blue did.  I’m really pleased with how these feel like they’re a living and interesting part of the scene, rather than just a flat piece of junk that always looks the same no matter where you see it or from what angle.  Perish the thought. 😉

Fighter

So the above is again the “before shot,” prior to today’s IBL work.  I was actually really happy with this one already.  Then here are a few angles of what it looks like now:

In some lighting angles, you can see that this one is really dark on some of the surfaces.  But there’s also a very metallic sheen to it.  From other angles the main color comes right back out, and from yet others there’s this kind of bluish shimmer that passes over it as the camera or the ship turns, either way.

I might need to make the cockpit a little brighter, I dunno.  Minor tweaks.

More To Come!

At any rate, the space dock and Ark and warp gate and planet controllers also really got a huge upgrade out of all this.  All the rest of the ships are still using the PBR approach, which looks similar-enough but not quite the same by any stretch.

This wasn’t really on my list of things to work on this week originally, but with Cinth having some major health issues and there also being some major health issues with a couple of my extended family members, it’s been a week where I wanted to focus on some things that were productive, but not quite as mentally taxing.  This was a tricky problem to solve, but not as tricky as some.

Anyway — enjoy!  Thanks for reading.

Chris