Metro: Last Light Graphics Breakdown & Performance Guide

By Andrew Burnes on Mon, May 13 2013 Featured Stories, Guides

4A Games’ Metro 2033 was a smash hit in 2010, impressing PC gamers with its incredible graphics and unique gameplay, which bucked the bombastic trend that permeated the ever more explosive shooters of that era. The story, too, was a cut above the rest, having been adapted from a Russian novel that went viral online before becoming a best-selling published work. Unsurprisingly, a sequel was commissioned, and tomorrow it finally goes live on Steam following three years of development.

Called Metro: Last Light, this long-awaited sequel offers a direct continuation of Metro 2033’s story, putting the player in the shoes of Ranger Artyom once more. Having done what was asked of him in 2033, regardless of the repercussions, Artyom must now explore long-forgotten sections of Moscow’s underground metro railway to confront his greatest fears, and to save what’s left of his post-apocalyptic world.

As one might expect, every element of 2033 has been improved and iterated upon for Last Light, which is a superior game in every regard. That isn’t to say 2033 was lacking, but unlike most blockbusters which come from seasoned developers with several titles under their belts, 2033 was the first release for the Ukrainians at 4A, and was built on a comparatively small budget to boot. These refinements will undoubtedly be discussed at length in the many reviews hitting the airwaves this week, but I will say that I haven’t been as engrossed and immersed in a first-person shooter and game world for quite some time.

What we will be looking at today is 4A’s self-titled 4A Engine, which powers the technology behind Last Light’s astounding graphics, and those that dropped jaws in 2010.

Article Contents:

4A Engine: Optimized & Efficient

4A Games’ proprietary 4A Engine is capable of rendering breathtaking vistas, such as those showing the ruined remnants of Moscow, as well as immersive indoor areas that play with light and shadow, creating hauntingly beautiful scenes akin to those from modern-day photos of Pripyat’s abandoned factories and schools.

Ordinarily, this level of detail would require gigabytes of system memory and GPU VRAM, but thanks to a highly efficient streaming system Last Light’s world uses less than 4GB of memory, and less than 2GB of VRAM, even at 2560x1440 with every setting enabled and maxed out. More impressive still is the fact that there are no streaming texture errors, or instances of textures visibly popping from low to high quality as the player moves through the world.

Similarly, CPU usage is fine-tuned for maximum performance, allocating tasks such as the rendering of physics effects or the playing of sound to any available CPU thread instead of pre-determining the rendering of physics to thread two, and sound to thread three. This ensures that every task is completed as quickly and efficiently as possible, and that every ounce of CPU power is used in the most demanding moments, improving performance by a considerable margin in comparison to traditionally-threaded games and engines.

Of course, it would be remiss of us to ignore 2033’s performance, which could certainly be classified as “unoptimized” when maxing out each of the game’s settings. As stated earlier, 2033 was 4A’s first game, and was built on a limited budget. Furthermore, one could also argue that 2033 was ahead of its time, featuring settings and technology that were more than the then-fastest GPU, the GeForce GTX 480, could handle. For Last Light, 4A focused on optimization from the off, rewriting code to be as efficient as possible, enabling Last Light to run significantly quicker than 2033, even with its new, more advanced features.

Underlining this drive for optimization is the removal of DirectX 9 and DirectX 10 from the in-game menus, rendering Last Light’s graphics automatically via DirectX 11. Extensive testing found the pair to be up to 15% slower than DirectX 11, even with the game’s DirectX 11 render path automatically enabling extra features. As gamers without an interest in tech will likely never learn of these render speed improvements, 4A default the engine to DirectX 11 to ensure that players receive the maximum level of performance at all times.

If you don’t have a DirectX 11-compatible graphics card, don’t worry; Last Light will determine the correct DirectX version for your hardware and enable it automatically. And if you wish to switch between DirectX 9, 10, and 11 manually, for whatever reason, the r_api option in the game’s user.cfg file will allow you to do just that.

Last Light’s Tessellation Examined

Making a head, a cup, or a light bulb look completely smooth and round in a game requires an unfeasible number of polygons that would reduce performance and would be of better use elsewhere to add entirely new objects and detail. With DirectX 11, developers can leverage GPU technology to ‘tessellate’ pretty much anything, adding the required extra detail for a comparatively minor reduction in frame rates.


This monster's teeth are even sharper, and its body smoother and more detailed through the use of tessellation.

In Metro 2033, 4A Games tessellated characters, supernatural enemies, and some objects, adding extra detail and rounding out surfaces to make them appear more realistic and less angular. For Metro: Last Light, 4A has tessellated anything and everything that would benefit, greatly improving the detail of every scene.


Click here to view an interactive comparison highlighting the benefits of object tessellation.

With tessellation disabled, it appears that the wall is uneven, but it is in fact a clever use of Parallax Occlusion Mapping (POM), a low-cost, high-speed technique that fakes the appearance of geometric detail using displacement maps similar to those required for tessellation. In the example above, the wall appears detailed on the right of the image, but as the view extends further from Artyom the illusion fails and the wall appears flat once more. This inability to adjust pixels beyond the immediate perspective of the player is the main drawback of POM, though it should be noted that it still offers a significantly improved level of image quality over the "Low", "Normal" and "High" Quality settings that disable the feature.

Referring to our wall comparison once more, note how the torch’s dynamic shadow falls flat against the supposedly uneven wall when using POM, and how it shifts and follows the shape of the stone when real geometric detail is added with tessellation. In Last Light, with its hundreds of deferred dynamic lights and many dynamic shadows, the addition of real geometric detail results in a dramatic shift in image quality in many scenes and areas, allowing light and shadow to fall in a nonuniform fashion, lighting a nook and shading a cranny, which simply isn’t possible using other techniques.

Below, you can check out another interactive example of tessellation, highlighting how it adds detail to characters, world objects, weapons, bullets, and other man made items.


Click here to view an interactive comparison highlighting the benefits of object tessellation.

All-new for Last Light is environmental tessellation, which adds extra detail to the world itself, making ground surfaces appear uneven and therefore more realistic.


Click here to view an interactive comparison highlighting the benefits of environmental tessellation.

In Last Light’s options menu, “Normal Tessellation” enables object, character and enemy tessellation, and “High Tessellation” introduces the extra environmental detail. “Very High Tessellation” adds no further detail, but does increase the maximum view range of tessellation from ten to fifteen meters, and the distance at which tessellation is rendered in full detail from seven meters to ten meters. In the five meters between the full detail and maximum detail view distances, a level of detail system dynamically reduces the quality of tessellation to maintain performance and prevent unsightly fade-in or popping.

PhysX: Powering Hardware & Software Physics

Like Metro 2033, Metro: Last Light uses PhysX to power both general physics and hardware-accelerated physics effects. With general effects, objects can be manipulated and destroyed, and characters fall realistically when killed. Dozens of smaller, less obvious, less exciting examples can be found throughout the game, and though each effect is of a high quality, with destruction being singled out for praise in particular, each effect’s realism is limited by the need to retain compatibility across all GPUs.

To enhance these effects, and to bring them to a level of quality on par with the game’s other cutting edge features, 4A has once again implemented NVIDIA GeForce GTX, GPU-powered PhysX effects, using the PhysX SDK. Each is realistically simulated, enabling effects to persist in the world, to interact with other game elements, to move without unrealistically clipping through geometry or objects, to be dynamically shadowed and self-shadowed, and to be manipulated by the player, other characters, and other effects. They are also automatically shaded, shadowed and lit like the game’s general geometry and objects, allowing them to blend in naturally without any additional work from 4A’s developers.

Used throughout the game to enhance everything from sparks to smoke volumes, these GPU-accelerated effects fall into a few general categories.

Debris & Destruction

Shooting a surface in Last Light results in the expected release of debris, and perhaps some sparks, too, should the surface be metallic. Enabling “Advanced PhysX” from the Game Options menu results in physically-led pieces of debris being emitted, which don’t immediately fade away like standard pieces. Each piece of debris and each spark collides with the terrain, bounces, and ultimately comes to a rest. As they do, each casts a shadow, and should other pieces and sparks be nearby they may cast their own shadows upon their comrades.

When in motion, the trajectory and movement of each piece of debris and each spark can be altered by collisions with other emitted elements, and with objects and surfaces. A prime example, is that of the sparks emitted from broken lights, which fall to the floor at speed, before arcing off following a collision with the terrain or an object. This same effect is used with embers, emitted by welders and furnaces, but with the added effect of natural, realistic dissipation, which sees the embers cool and fade as they fall and bounce.


Destroying objects like windows, pillars, barriers, tiled walls, and boxes sees the remnants fall, bounce, and persist in the environment. And like pieces of debris these can be further manipulated by the player, other characters, and other effects. Each retains the properties of their original form, too. So for example, when compared to chunks of concrete, destroyed tiles will bounce further when initially knocked off a wall, and move further when subsequently manipulated because they are lighter and smoother, and therefore generate less friction.

Without PhysX’s hardware-accelerated enhancements, the destruction of the objects will be pre-canned, the destroyed pieces will fade away as they generically fall, and the general destruction effect will be less exciting.


Explosive Enhancements

Like gunshots, explosions result in the emission of extra physics-led particles when hardware PhysX is enabled. The difference here being the propelling of pieces through the force of the explosion, and the interaction of the explosion with other objects and physics-led effects. Furthermore, 4A was able to hand-tune the force of each explosion, ensuring an explosive barrel emits a greater degree of force than a small handheld grenade, directly affecting the maximum distance that debris can be propelled, adding a further element of realism to the effect.

Most impressively, the force of each explosion dissipates with distance, resulting in a cardboard box at the edge of the explosive radius being obliterated, and a denser concrete object barely being scratched. With regards to windows, the strength of the explosion and the distance from its epicenters determines the force at which shattered glass is propelled. Up close the glass will be launched across the room; at range it merely cracks and falls to the floor.


Fog Volumes

Metro: Last Light’s immersive scenes are filled with volumetric effects like fog, steam, and smoke, helping immerse the player in the world. With hardware PhysX enabled, many of these effects are rendered as real-time Fog Volumes solely using PhysX particles, enabling the effects to float around the environment, collide with one another, and react to external forces, like the explosions detailed earlier.

Through the PhysX Smoothed-Particle Hydrodynamics (SPH) SDK, 4A were able to fine-tune the properties of each effect, enabling heated smoke to rise and dissipate, outdoor fog to drift across the scene, and cooled vapor to persist at the foot of a walk-in freezer. These SPH particles are further enhanced in Last Light through the replication and simulation of real-world compressible fluids, enabling the player to walk through Fog Volumes, look down, and see the particles realistically shift around Artyom’s body.

Without hardware-acceleration, players will still see visually arresting, non-interactive particle effects with pre-baked, scripted movement that occurs regardless of player interaction.


Cloth

In the dilapidated world of Metro: Last Light, “pristine” is a long forgotten word. Walls and floors are grimy, dust obscures fine detail, and cosmetic niceties that meant so much are now left to rot as the Metro’s inhabitants struggle to survive. In the case of banners, flags, drapes, and other pieces of cloth, years of exposure to the elements have left them looking tattered and worn, and as the wind whips through the abandoned tunnels the cloth billows in the breeze.

Without hardware PhysX enabled, players will see non-interactive, static pieces of cloth in certain locations, and no cloth in others.


For more on PhysX, and a look at the effects in-action, check out our Metro: Last Light technology video:

Anti-Aliasing: Now Supersampled

By default, Metro: Last Light utilizes 4A’s proprietary Analytical Anti-Aliasing (AAA) to lessen the impact of jagged, aliased edges on geometry, objects, characters, transparent textures, and all other screen elements. A combination of FXAA and 4A tech, AAA improves upon other post-processing anti-aliasing techniques by doubling the internal resolution of the picture using pattern and shape detection, and downsampling the post-processed result back to the user’s screen resolution, resulting in an anti-aliased image that is far smoother and clearer than traditional post-process techniques can create.

In Metro 2033, players could utilize Multisample Anti-Aliasing (MSAA) instead of Analytical Anti-Aliasing to generate an even sharper, less aliased image. Unfortunately, due to 2033’s deferred lighting, the performance impact of MSAA was tremendous, making its use unfeasible on anything other than a three or four multi-GPU system when every other setting was enabled and maxed out. For Last Light, 4A has replaced Multisample Anti-Aliasing with Supersampling Anti-Aliasing (SSAA), which creates a significantly smoother, more detailed image by internally rendering every element of the screen at a higher resolution. In other words, on a player's 1920x1080 monitor, 2X SSAA renders Last Light at 2688x1512 on the GPU before resizing the image to 1920x1080, increasing the amount of detail per pixel. At 3X SSAA the downsample resolution increases to 3264x1836, and at 4X SSAA it is 3840x2160, the resolution of next-gen “4K” monitors and screens.

To ensure maximum anti-aliasing quality, 4A continue to use AAA even when SSAA is enabled, simultaneously drawing on the strengths of both techniques. And because SSAA supersamples everything, AAA is also supersampled, doubling in quality when 4X SSAA is enabled.


Click here to view an interactive comparison highlighting the benefits of Supersampling Anti-Aliasing. Note the increased detail in the environment, on the fence, on the tree, on the grass, and on the particles when using SSAA.

For a closer look at the detail SSAA can expose, check out the enlarged comparison below.


Click here to view an enlarged interactive comparison that better shows the improvements SSAA can introduce.

With a bit of technical know-how and the right hardware you can already downsample in games from resolutions higher than that of your screen, such as the aforementioned “4K” resolution, 3840x2160, increasing visual detail considerably. Last Light's SSAA has a clear advantage, however, in that is built directly into the game code, is optimized specifically for Last Light, has a much lower performance impact than other downsampling techniques, and can correctly anti-alias edges unlike general downsampling achieved through GPU scaling. In those cases, additional in-game or injected post-process anti-aliasing is required, further lowering the frame rate.

Compared to Metro 2033’s anti-aliasing, Last Light’s ‘super HD’ solution is far superior, and far faster.

Quality: Fourteen Settings Rolled Into One

Of Last Light’s settings, “Quality” has the greatest impact on fidelity, adjusting fourteen hidden settings as the option is raised and lowered.


Click here to view an interactive comparison showing Very High versus High, here for Very High versus Normal, and here for Very High versus Low.

Very High High Normal Low
Ambient Occlusion Precomputed + SSAO Precomputed + SSAO Approximate Approximate
Analytical Anti-Aliasing Enabled Enabled Enabled Enabled
Bump Mapping Precise Precise Coarse Coarse
Detail Texturing Enabled Enabled Enabled Disabled
Geometric Detail Very High High Normal Low
Image Post-Processing Full Full Normal Normal
Light-Material Interaction Full Normal Normal Normal
Motion Blur Camera + Objects Camera Disabled Disabled
Parallax Mapping Enabled + POM Enabled Disabled Disabled
Shadow Filtering Hi-Quality Hi-Quality Normal Fast
Shadow Resolution 9.43 Mpx 6.55 Mpx 4.19 Mpx 2.35 Mpx
Skin Shading Subsurface Scattering Simple Disabled Disabled
Soft Particles Enabled Enabled Disabled Disabled
Volumetric Texturing Full Quality + Sun Shafts Low Precision Disabled Disabled

Wondering what each setting does, and how it improves image quality? Let’s take a deeper look.

In Last Light, 4A uses an approximated technique on "Low" and "Medium" to add a basic level of AO to low-end configs, helping to improve fidelity by a fair margin. On "High" and "Very High", fast pre-calculated AO is applied to the lion’s share of the game world, and Screen Space Ambient Occlusion (SSAO) is enabled to render higher-quality real-time AO on objects and surfaces players come into close contact with, and are likely to see affected by dynamic lighting, dynamic shadowing, and other effects.

Ambient Occlusion

AO will be familiar to most gamers thanks to its frequent use in modern-day games, and through the option to add it automatically to many more via the NVIDIA Control Panel. In short, AO adds contact shadows where two surfaces or objects meet, and where an object blocks light from reaching another nearby game element. The AO technique used and the quality of the implementation affects the level of accuracy of the shadowing, and whether new shadows are formed when the level of occlusion is low. Technologically there’s more to it of course (if you’re interested, learn more here), but the long and short of it is that Ambient Occlusion increases the realism and fidelity of a scene by calculating the visibility of light in real-time. Without Ambient Occlusion, scenes can look flat and unrealistic, and objects can appear as if they are floating on surfaces.


To compute the occlusion of every light source, object and surface in real-time, in a deferred renderer game with hundreds of lights per scene would be computationally inefficient and force a reduction in quality of other game settings to retain a playable frame rate. 4A’s "High" and "Very High" solution therefore gives players the best of both worlds and increases image quality considerably when compared to other titles that merely include real-time, local area AO.

Analytical Anti-Aliasing

As discussed earlier, 4A enables their FXAA-Custom Post Process AAA anti-aliasing technique automatically, regardless of the game settings chosen, and even when using SSAA.

Bump Mapping

Bump Mapping is one of the oldest techniques in 3D computer graphics, adding fake ‘bumpy’ detail to objects and surfaces that would be too expensive to fully render with polygons or tessellation. This could be because the objects and surfaces are too far from the player’s view, because they are too large and therefore too expensive to render, because they are too small to benefit from real geometric detail, or simply because they are a piece of scene detail that won’t be looked at closely, the classic example being an orange in a bowl of fruit.

In Last Light, 4A use a basic implementation on "Low" and "Medium", and a precise implementation on "High" and "Very High".

Detail Texturing

Detail Texturing increases the visual quality of a textured surface when viewed up-close by blending a second texture in with the first. Commonly, developers use this technique to make the textures of outdoor areas appear detailed up close by introducing the second higher-quality texture as the player nears. At distance, a single lower-quality texture is used on the terrain, allowing performance to remain high even when viewing expansive vistas.

In Last Light, 4A’s textures are predominantly 2048 pixels wide by 2048 pixels high, double the resolution of textures in many of today's best-looking games. Using these 2048x2048 textures at range creates highly detailed distance views, and up-close with the introduction of a second 2048x2048 texture the visual quality of surfaces skyrockets.


Click here to view an interactive comparison highlighting the benefits of Detail Texturing.

Emphasizing the importance of Detail Texturing, 4A enables the setting on everything other than "Low".

Geometric Detail

As the Quality setting raises, so does the level of detail in the world, increasing the visual complexity and quality of buildings, objects, characters, the terrain, and other game elements.

Image Post-Processing

Switching from "Low" and "Medium" to "High" or "Very High" unlocks Last Light’s full range of post-processing effects. These include, but are not limited to, High Dynamic Range lighting, bloom, Blue Shift, Tone Mapping, camera-style exposure adaptation, real-time color correction, film grain, full-scene noise, and depth of field out-of-focus rendering.


An example of Blue Shift in action.

In Metro 2033, depth of field crippled frame rates on anything other than the best systems. In Last Light, the effect has been heavily optimized and integrated directly into the post-processing pipeline, removing the dedicated “DOF” game option found in 2033.

Light-Material Interaction

In many games you’ll find a “Shader Quality” option, which adjusts the quality of light interactions with surfaces, as well as the quality of other effects, such as reflections, parallax mapping, HDR lighting, and so on and so forth. For Last Light, 4A Games has broken the catch-all Shader Quality option into its composite pieces, giving them a greater degree of control over each individual effect.

Light-Material Interaction therefore does as the name suggests: it defines how light interacts with materials, such as wood, glass, metal, and dirt. In our interactive example below you can see the setting in action, with Low, Normal and High’s “Normal Light-Material Interaction” on the left, and Very High’s “Full Interaction” on the right.


Click here to view an interactive comparison highlighting the benefits of Light-Material Interaction.

In the comparison there are several areas to examine, most prominent of all being the light’s interaction with the desk. With “Full Interaction”, the wood lacquer shine is more vibrant and nonuniform due to the accurate calculation of the light’s strength, and the reflective quality of the desk in that specific spot.

Directly above the shine we see a Metro helmet. With “Full Interaction” enabled, the direction and intensity of the lighting is accurately rendered, and the effect of the visor on the lighting is calculated, resulting in the inside of the helmet being shaded and shadowed correctly. On the exterior of the helmet, visibility of its surfaces is calculated, increasing the intensity of the lighting directly below the lamp’s bulb, and increasing the quality of the shadowing below the rim of the visor and on the curved edge facing away from the lamp.

And finally, focus on the bottle. Most obviously, the shine and shading is improved, as in previous examples, but look at the base and you’ll note that the light emitted from the far side of the bottle is brighter and more accurate when using “Full Interaction”. Furthermore, the light is nonuniform, being brighter where the light passes directly through the glass, and dimmer where it also passes through the bottle’s label.

This much-improved level of interaction can be seen in every room, tunnel and area in the game, making "Very High" Quality the recommended setting to enable first above all other options.

Motion Blur

Motion Blur is a contentious setting online, receiving as much love as it does derision. In Last Light, 4A has used the option sensibly, ensuring the entire screen doesn’t blur into an unrecognizable smudge whenever the player’s perspective shifts by even the slightest amount. Instead, 4A applies velocity-specific blur that can be fine-tuned and focused, preserving detail whilst simultaneously adding a high-action, high-speed feel to fast-paced scenes.


A screenshot showing variable object-based motion blur.

On "Low" and "Medium" Motion Blur is disabled, and on "High" the player’s camera is blurred. On "Very High", all objects, characters and enemies can be independently blurred, and to differing degrees. For example, whilst standing still the general view will remain sharp and detailed, any monster lumbering towards the player is moderately blurred, and spent casings ejected from a weapon are heavily blurred.

This Object Motion Blur is enabled only when using "Very High" Quality with DirectX 10 and DirectX 11. The "Motion Blur" game option, meanwhile, merely adjusts the amount of camera motion blur, allowing the effect’s detractors to reduce its impact on high-action scenes.

Parallax Mapping

Parallax Mapping performs a similar duty to Bump Mapping, adding simulated detail to walls and other surfaces that would be too expensive to render with polygons or tessellation. A more-modern technique, its quality is a step-above Bump Mapping, making it more suitable for surfaces and objects viewed up-close.

With "Very High" Quality enabled, Parallax Occlusion Mapping (POM) is added to the mix, increasing the detail of the simulated effect yet again, and allowing for the use of self-shadowing on POM’d surfaces. This dramatically increases their realism and fidelity, which is especially important in a deferred renderer game like Last Light that relies heavily on light and shadow. As mentioned, POM simulates the appearance of tessellation when "High" or "Very High" Tessellation is not enabled, enabling the game world to appear highly detailed on slower systems.

Primarily, POM in Last Light is used in large open areas filled with detail, and on large surfaces such as building walls that cannot be examined closely. In these cases adding tessellation would prove unfeasible due to the number of tessellated triangles required. If spare performance were available, the use of it for rendering massive amounts of tessellation would be pure inefficiency, as other effects with a superior cumulative improvement on quality could instead be introduced.

Shadow Filtering

An essential feature in a shadow-heavy game like Last Light, Shadow Filtering softens and smooths the edges of shadows, removes visual artifacts, and eliminates shadow dithering. "Low" Quality uses “Fast Filtering”, "Medium" Quality “Normal Filtering”, and "High" and "Very High" Quality, “Hi-Quality Filtering”.

Shadow Resolution

To create natural-looking shadows in real-time, a high shadow map resolution is required. As the Shadow Resolution increases so does the quality of every game shadow, enabling them to better replicate the shape of the shadow caster, be that a mug or a building, or a moving person.

Taking the example of the mug, a low shadow resolution will result in a general shadow of the mug’s body, but at higher resolutions the detail of the handle will also be replicated. In the case of moving objects, such as people, higher resolutions are vital for realism as Last Light's dynamic, real-time shadows can fall across tessellated faces and bodies. A low resolution shadow would therefore appear out of sorts with a detailed character, ruining immersion.

In Last Light, “Low" Quality nets players a Shadow Resolution of 2.35 megapixels (Mpx), “Medium" Quality 4.19 Mpx, “High" Quality 6.55 Mpx, and “Very High" Quality an unprecedented 9.43 Mpx. It’s also worth mentioning that regardless of the shadow resolution, umbra, penumbra, and variable penumbra are calculated and applied to add distance, occlusion-based depth and variability to shadows. If you're unfamiliar with the terms, umbra replicates the darkest area of a shadow directly behind an object occluding a light source, and variable penumbra softens shadows as the distance between the end point of the shadow and the shadow’s source increases.

Skin Shading

Similar to Light-Material Interaction, which controls the interaction of light with non-organic surfaces, Skin Shading determines how light interacts with the skin of human characters. On "Low" and "Normal" Skin Shading is disabled to maintain performance; on "High", “Simple Shading” is enabled, offering a rough approximation of "Very High’s" technique, which is called “Subsurface Scattering”.

Designed to tackle the ‘plastic wax’ phenomenon, whereby light hits a character and simply bounces back as if the character were made of plastic, Subsurface Scattering calculates the strength and direction of light rays as they hit and penetrate a character’s skin, scattering the rays realistically and allowing the light to exit at multiple locations if of a sufficiently high intensity. For a real world example, shine a torch through a hand in a dark room and observe how the light continues through to the other side of the hand, and illuminates the darkness.


Click here to view an interactive comparison highlighting the benefits of Subsurface Scattering.

Such a vivid example will rarely be found in-game. Instead, Subsurface Scattering is more readily seen as variable shininess on foreheads, and lighter skin tones on fringes of body parts occluding light sources, adding an extra layer of fidelity and realism, putting the image quality of Skin Shading on par with Last Light’s other high-quality settings.

Soft Particles

Particle effects with depth, like smoke, fire or fog, are typically squares comprised of sprites, overlaid on the screen to simulate the appearance of dynamic particle effects. These face towards and follow the camera’s viewpoint like sprite trees from early 3D titles, which eerily shifted and followed the player’s view. In open environments this is a perfectly acceptable, high-speed solution for simulating particle effects, but in enclosed rooms the sprite square often intersects with geometry, revealing visible lines where the two meet. This shatters the illusion of the effect and prevents it from appearing as intended.

To rectify the problem ‘Soft Particle’ techniques are applied, enabling the effect to appear correctly when viewed from all angles, regardless of object or surface intersection. Often, Soft Particle techniques have secondary benefits, in that they allow developers to specific the opacity and transparency of each pixel of the square, resulting in a superior simulated particle effect.

In Last Light, "High" and "Very High" gain the use of Soft Particles, helping to improve the quality and fidelity of the game world when compared to "Low" and "Normal". To see real dynamic particles on-screen, you'll have to enable Advanced PhysX.

Volumetric Texturing

Soft Particles may be superior to Hard Particles that clip when intersecting with geometry, but ultimately their use of sprites limits their quality and the ways in which they can be manipulated. A more modern, more flexible technique called Volumetric Texturing allows 4A to create improved effects that are more suitable for up-close examination.

Constructed from three-dimensional textures, as opposed to 2D sprite squares, Volumetric Textures allow 4A to generate smoke, fog, and fire effects that display a high level of detail when viewed at extremely close range. But though Volumetric Textures are heavily optimized and assignable to any available CPU thread like other game tasks, distance particle effects will still commonly be constructed from Soft and Hard Particles to ensure optimum performance, and to minimize memory usage.


In addition to generating volumetric particle effects, Volumetric Texturing is also an excellent solution for creating thick layers of grass and fur with a minimal performance impact, and for creating detailed sun shafts as seen in Last Light when "Very High" Quality is enabled. On "High", low-precision Volumetric Texturing is applied to the world and Volumetric sun shafts are disabled, and on "Low" and "Normal" the Volumetric Texturing technique is itself disabled.

Optimal Playable Settings

The best way to automatically configure and apply Metro: Last Light’s game options for your specific system configuration is through GeForce Experience, our new application that optimizes your games, updates your drivers, and streams PC games to your Project SHIELD handheld. Taking into account your GPU and CPU, as well as many additional factors, GeForce Experience’s recommendations can be applied with a single click and will be updated over time should developer updates and NVIDIA drivers improve performance further still. On that note, make sure to download and install the new GeForce 320.14 beta drivers, through GeForce Experience or our site, to improve performance by up to 10% in Metro: Last Light.

The below recommendations were generated through extensive benchmarking and testing in the game's most demanding moments, with the intention of maintaining a frame rate of at least 40 frames per second during the biggest, most action-packed set pieces, ensuring a silky smooth experience at all times. Please note that our recommendations may differ from those in GeForce Experience if you use a Dual Core CPU or older Quad Core CPU, like the Q6600.

1920x1080 OPS Quality Advanced PhysX Tessellation SSAA
GTX TITAN Very High On Very High 2X SSAA
GTX 690 Very High On Very High 2X SSAA
GTX 680 SLI Very High On Very High 2X SSAA
GTX 670 SLI Very High On Very High 2X SSAA
GTX 680 Very High On Very High Off
GTX 670 Very High On Very High Off
GTX 660 Ti Very High On Normal Off
GTX 660 Very High On Off Off
GTX 650 Ti BOOST Very High On Off Off
GTX 650 Ti High Off Off Off
GTX 650 Normal Off Off Off
GTX 580 Very High Off Off Off
GTX 570 High Off Off Off
GTX 560 Ti Normal Off Off Off
GTX 560 Normal Off Off Off

As you can see, our claims about Last Light’s optimization hold true. On a GeForce GTX 650 Ti Boost, Last Light runs at 40 frames per second, or more, at all times when using "Very High" quality settings. Stepping up to a GTX 660 allows for the use of hardware-accelerated PhysX effects that enhance most scenes, and with a GTX 670 plugged-in Tessellation can be enabled, adding extra geometric detail to objects, characters and the environment.

On the top-end of the GPU scale, 2X Supersampling Anti-Aliasing increases detail by 1.4x on the GTX 670 SLI, GTX 680 SLI, GTX 690, and GTX TITAN, resulting in an effective resolution of 2688x1512 at 1920x1080. Without SSAA, each config can be cranked up to 2560x1440 or 2560x1600 on higher-resolution monitors.

At 2560x1440 or 2560x1600, players will require 2-Way SLI GTX TITANs, 3-Way SLI GTX 670s, 3-Way SLI GTX 680s, or Quad SLI GTX 690s to enable 2X SSAA, resulting in an effective resolution of 3584x2016 at x1440, and 3584x2240 at x1600. On the Quad GTX 690s, higher levels of SSAA should also be possible.

You may also be interested to know that Metro: Last Light launches with full Surround multi-monitor support, 3D Vision support, and 3D Vision Surround support, immersing the player in the action through the use of three 120Hz stereoscopic 3D widescreen monitors. Performance data has yet to be run on those configurations, but one can predict that a high-end system will be required when using max settings, based on our single-screen results.

Conclusion

As is evident from the reams of technical info in this article, Metro: Last Light is one of the most technologically and graphically advanced games ever released, using the latest techniques and solutions to attain an unprecedented level of image quality. And thanks to continual optimization that occurred throughout Last Light’s development, Last Light runs significantly faster than its predecessor, even with the extra settings and new cutting-edge features.

This optimization enables the entry-level GeForce GTX 650 Ti Boost to render Last Light’s full suite of fourteen Quality settings at Very High, maximum detail levels. For hardware-accelerated GPU effects a faster GTX 660 is recommended, and for tessellation we found a GTX 670 to be necessary to maintain a minimum of 40 frames per second at all times whilst simultaneously using Very High settings and PhysX. Beyond this level only Supersampling Anti-Aliasing and resolution can be changed, both of which required faster SLI configurations or a single GTX TITAN in our testing.

Metro: Last Light shows what the latest GPUs are capable of when properly utilized, and offers an early look at the next-generation of games, which will be playing catch-up in 2014 and beyond.

If you require a new video card for Last Light, our Metro: Last Light GeForce GTX GPU Bundle includes a free copy of the game at participating retailers and e-tailers. Learn more here.

Comments