With over 2,000 developers and an estimated $100 million budget, fans had a right to expect high production values from The Last of Us 2. While opinions naturally vary, the award-wining game succeeded in offering impressive graphical fidelity. Naughty Dog was so committed it overhauled part of its rendering software to make sure one detail was precisely perfect.

The Last of Us 2 technical art director Waylon Brinck and technical artist Steven Tang gave a presentation at a graphics conference earlier this year. They talked about the intense work that went into rendering the character’s eyes.

RELATED: The Last of Us 2 Player Finds Hidden Abby Reference in Jackson

As the old saying goes, the eyes are the windows to the soul, and eye contact is indeed a significant part of human communication. For those reasons, Naughty Dog worked hard to make The Last of Us 2 characters’ eyes as realistic as possible. After all, time and money spent on hair animation and skin textures don’t count for much if characters are staring creepily at the player with glassy eyes. This proved to be a significant undertaking, as the studio had to completely overhaul the software used to render characters' eyes.

As Brinck pointed out, Ellie had very realistic eyes in The Last of Us 2’s reveal trailer. However, that was largely thanks to careful lighting and camera angles. Overcoming this limitation in-game was a lengthy process that began with taking numerous reference photos. After that, the team applied “screen space shadows” to the character’s eyelids and lashes. That’s a type of ambient occlusion that utilizes ray tracing to accurately depict how light interacts with a 3D model. It gave the character’s eyes much-needed depth, resulting in a more realistic and relatable appearance.

Human eyes weren’t the only ones to get special treatment either. As Brinck and Tang explained, the team was working on giving taxidermied wolves “retro-reflective eyes.” This is a common trait of naturally nocturnal animals, where their eyes reflect light differently depending on the brightness level. It’s the reason dogs’ and cats’ eyes appear to glow in the dark. Naughty Dog managed to simulate it by writing a piece of code to calculate the reflectiveness of the pupil. The game engine then applied an iridescent glow to the animal’s eyes. The developers liked the effect and applied it to all Infected enemies in The Last of Us 2. The result was zombified creatures that looked even more unsettling.

Altogether, this may seem like a lot of work for comparatively minor details. However, the developers believed it was an essential step toward immersing players in the game’s world and story. And while The Last of Us 2 was not without controversy, no one can accuse Naughty Dog of skimping on the details.

The Last of Us 2 is available now on PlayStation 4.

MORE: The Silence Around The Last of Us 2's Faction Multiplayer is Concerning

Source: Kotaku