Thursday, 31 August 2017

Engine Change: Life is Strange

There has been a lot of discussion of the "fingerprint" of an engine recently. Does it matter to people who play games which engine has been used? Are we beyond an era when Unreal Engine games are desaturated brown blobs that slowly stream in the high detail textures several frames after the camera gets there or Unity Engine games are limited by the lacking level geometry options for efficient map construction? Generally the answer is yes, but there are still some things which you can choose to use from the default engine configuration that make things visible (beyond license deals to save money by showing the splash screen of the engine when you start the game - seriously publishers, pay to not show the dang logo; you can afford a proper premium license).

It's important to note that anything can be rebuilt on top of or in replacement of anything that ships by default in a major engine. Most of them now offer source code access rather than forcing developers to work in a scripting language to do their gameplay code and locking up the engine as a binary blob you can't poke and rewrite (traditionally something that was prohibitively expensive to license access to). Everything on the GPU is just a shader and you can write your own, the fingerprints can come from which shaders are in the examples directory or part of the effects package that is offered with an engine. If you want a depth of field effect, there's probably a well optimised version tuned in your engine options rather than rolling your own and possibly making some trivial mistakes (or some incredibly subtle ones that only pop up on unusual hardware platforms). If you're using physically based lighting then your engine probably has one specific way of doing that with a load of default parameters for exactly how it looks.

With the move from Unreal to Unity, let's explore that in Life is Strange. The interface immediately shows you where the Unreal Engine is an extremely mature option. Everything feels good to just move around with either mouse or joypad. Opening Before the Storm, Unity's UI (at least the iteration being used here) shows less polish. The deadzones that come with sensible defaults in Unreal are here unable to deal with the slight wobble on my old 360 stick. Is the deadzone still only 0.001 here? That does not feel like the 0.1-0.2 deadzone of sticks in something like Halo or Gears - something that should possibly be set even wider in a UI where you're only using the stick as a digital four-way most of the time.

From the very opening screens it is clear that these two games in the series are not going for the same look. We can highlight a few things here from a technical perspective. LiS has a very strong directional blur around the edge of the scene with strong chromatic aberration effect (the blur size is different for each colour, causing fringes) that's missing in BtS. Meanwhile, BtS immediately shows a high quality blur effect being used to create depth of field (which we see in LiS itself but not in this menu, where a thick fog effect really paints a haze onto the bay). There are also a thousand little things about how the lighting is calculated and the tone mapping used to resolve that to the final image which lead to very different results.

But outside of the technical, look at the art. These scenes are more than technically using slightly different technology and effect choices. LiS is always painted with a style that invokes a rectangular brush and that's already apparent here. Leaves to tree shapes to houses, to the white cliffs - it's all being textured for this very specific impression of a certain painting style, faking what would be brushstroke type despite being a clearly polygonal construction. Just look at the leaves on that main tree on the left in BtS - speckled with perfectly circular dots to give the impression of detail and the tree bark, while showing some of the rectangular blocks of colour, breaks them with far too much heavy detail texturing so the brush effect is lost. This is an artistic difference we will see throughout the comparison. It's not the engine that's providing the biggest cues to a changing style but the choices of the art director and other artists on the projects.

Here we finally pick up on that chromatic aberration in BtS but toned down to the point where we only just pick it up in the bottom of the scene (and will continue to only just catch it in the rest of these screenshots). But we can also see that the high quality blur is being used to good effect in this dark scene along with some decent light cones to make this 1337 jump out in the very first scene of the game.

But I still miss the visual style of the original game. Despite the night vs day difference here, I find that things like the heavy fog over a high quality blur make for a more satisfying result which highlights the texture work. It's rough and like the chromatic aberration, it's got absolutely no interest in even pretending to hide itself. It charms me, much like that characters in the game.

When blur is used here in LiS, it's that smearing effect that gets caught out on the polygon edges in the foreground. I know the technical reasons why and I'd avoid it 99% of the time as long as I could afford to use a more expensive DoF system but here, here it reinforces the blocky presentation. Yes, a deep blur is used in spots but it never seems to totally overwhelm the angular stroke edges it smoothes over. I will always look at the BtS depth of field and feel the roundness of it bringing out the smoothness of the scene in contrast to the more angular blocky LiS texture.

Clearly, with objective eyes to the technical details, Chloe is improved in BtS. The eyes immediately show more of a spark of life, there's an attempt to bring the characters towards a slightly cartoon end of realism and it comes with better facial animation and far closer to what you'd expect from CG actors. We will have to see how the quality is received after LiS ran into quite a lot of comments about the lip-sync that showed some had troubles connecting with the characters which getting caught up on technical details of the presentation.

LiS opened front and centre with some strong technical effects that highlighted the art direction and brush style being invoked. Water fell and left rectangular patches of wet to reflect the light, the simple models and texture style jumped out and reinforced that opening menu vista while showing off a familiarity with real-time effects around lighting that merged well with the more classic approaches like using fog to tint the scenes in a less photo-realistic style that built on those base textures. Effects were rarely subtle but it provided a very distinct final look. I am interested to see where BtS goes with this new approach which still nods to the old visuals while removing any rough edges.

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