During our recent visit to Moscow, we talked shaders, CPU scaling and DirectX with Metro 2033’s Chief Technical Officer, Olez Shishkovtsov. If you’re the kind of gamer who is truly nerdcore, and knows the difference between antialiasing and anisotropic, this is the interview for you.

games.on.net: Metro 2033 is using a new engine; what are some of the major graphical specialties of this engine?

Olez: We’ve done a lot of things which are mostly dictated by the atmosphere, by the environment. For example, very few games do volumetric effects – lighting, fogging. But when there is dust in the air, and there is a lot of it in Metro’s tunnels, we basically have to do it. This was somewhat difficult in terms of performance, as there is a lot of it. It’s kind of unusual to see it in the game at all.

We focused on a few really basic things. For example, even if you don’t enable hardware antialiasing in the game, everything will still be fully antialiased – maybe not to the extent possible with the full hardware support, but still antialiased.

This is done mostly by morphological analysis of the scene. We run a lot of compute shading, where we analyse the scene before it is shown to the user. It’s done every frame, and we can correct a lot of small inconsistencies before the user sees the scene.

games.on.net: This game is a cutting edge PC game. Was it hard to squeeze these visuals on to the Xbox 360 as well?

Olez: Yes and no. Xbox is a fixed platform, you have all the access to the hardware and you can do a lot of cool stuff way, way cheaper than on PC. So the Xbox’s graphics quality is not of a low quality PC, it’s actually better than a middle-range PC.

games.on.net: Have you had to disable any features for the 360 version?

Olez: There are a few things. We don’t have quite the performance on the 360. For example, local motion blur, where your hand moves and it has a trail – it can be done, but we’re left without performance if we do that. On the 360, you always have to run it with a guaranteed frame rate, within a certain budget.

games.on.net: Speaking of which, what frame rate are you targeting on the 360?

Olez: The 360 is always running at thirty. We try to run at 30 as well for PC, maybe a bit more because of v-synch.

games.on.net: Does your game takes advantage of multiple CPU cores?

Olez: Yes, it was a decision way, way before the engine was even in prototype. It was multithreaded from the start.

games.on.net: So if I go from a dual to quad core, what performance increase can I expect?

Olez: If you are not bottlenecked by the video card, we have linear scaling – so double the performance. This goes all the way up to eight and sixteen cores.

games.on.net: What about GPUs? How does it scale with multiple GPUs? Have you optimised the game for multiple GPUs?

Olez: GPUs are different to the CPUs. Yes we did optimise, but it’s mostly in the hands of NVIDIA and ATI, and so on. With NVIDIA we now have linear scaling as well. With ATI, we’re still working on it.

games.on.net: Can you talk about PhysX and what this will add to the game?

Olez: We’ve done a lot of stuff with PhysX fluids. A lot of stuff with particles too, and there is a lot of destruction in the game. Destruction will be more lifelike with PhysX. Everything can destruct even without NVIDIA hardware, but with NVIDIA hardware it has much better fidelity.

There are a few things specific only to NVIDIA hardware. But as a game developer, we don’t want those to affect gameplay – it’s mainly visual fidelity, like smoke the smoke effects.

games.on.net: What do you prefer developing for – PC or console?

Olez: I prefer both. For example, I really enjoy DirectX 11. It brings power back to the developers. It’s a big, big step forward. For example, the compute shading is the way of the future. It’s kind of a CPU in your GPU, that allows a lot of different stuff not available before.

games.on.net: What about DX11’s tessellation – is it really all that?

Olez: In our game, it’s only used on characters – not on the environment. Characters are usually more important though.

games.on.net: Does your engine handle large open areas as well as the smaller tunnel environments, given that Metro 2033 is focused more on the claustrophobic environments?

Olez: Yes, it does. We primarily focused on the small areas because of the settings in the story, it’s not a fundamental limit of the engine. There are a few levels which are really big in Metro 2033.

games.on.net: What are the system requirements to run the game at full detail for a PC user, everything turned on, at 1680 x 1050 resolution?

Olez: At that resolution, the last generation of high end hardware – a single GPU NVIDIA card - will suffice. The new generation of cards from ATI, and we’ve seen the new ones from NVIDIA too, they’re way more powerful. With these you can turn everything on, with image enhancing features such as Super Sampling of every surface and every texture. Everything will be more detailed with this – not just edges.

games.on.net: What are some of the tricks your AI can do – we’ve heard it can smell. How does smell differ to say, hearing?

Olez: Actually, it’s a trick. Smell is an inaudible sound. Basically it’s the same system as audio. We use wave propagation to propagate the sound. The same system allows you to propagate a smell.

games.on.net: Metro 2033 uses high dynamic range audio. What will that mean for the gamer – how does it make the game sound different?

Olez: It’s really, really simple, and the same with video. When there is a bright sound - a loud sound or in the lower frequencies – they are always audible. Everything is scaled down and the most important sounds are audible. Everything is rebalanced, every frame. There are no situations when you just shoot and hear somebody near you talk, both sounds are on the same level. There are no such things. Instead, you shoot, and you hear nothing except the gun, because that’s how it works in the real world.

games.on.net: Is your engine going to be moddable?

Olez: Yes, but it’s mostly a question for THQ about whether they allow it...