When CryTek was tasked with creating visually stunning game for the Xbox One, they found themselves with a problem to solve: how to create an experience that would show off the graphical fidelity of the console on a weaker hardware than their usual PC target?
The technology and solutions they used were explained in depth during a panel at the Game Developers Conference titled “Moving to the Next Generation – The Rendering Technology of Ryse”, hosted by Senior Rendering Engineer Nicolas Schulz.Here’s what we learned from the panel:The project had a small team of rendering engineers fully dedicated to the game.It was designed as a “visual showcase” for the Xbox One from the get go despite the fact that the target hardware was less powerful than the usual PC target CryTek used.This created a major challenge: How can you still get people excited for next-gen visuals?Since Crysis 3 was already a visually rich game just adding more visual fidelity wasn’t an option on weaker hardware, and post processing was already maxed in the previous generation. That pushed CryTek to focus on the details instead, like shading, material definition, lighting quality and global illumination effects.The developer wanted to escape the usual “gamey” look, and to get closer to CG film quality by implementing well recognizable materials, a clean image with no aliasing and soft, realistic lighting.Physically Based Shading was used for the game, creating an interaction between light and materials similar to the real world. This had considerable implications as it enforced a plausible material model and defined clear rules for assets, enhancing consistency across the board. It also involved More complex BRDFs (bidirectional reflectance distribution function), Fresnel, normalization of specular highlights, energy conservation in general.The lighting model was especially affected as the developer had to be careful to preserve material integrity.The Oren-nayar model was used for BDRF, as it takes in account retro-reflection based on surface roughness. It improves quality for rough materials like stone, but it still offers similar results to the traditional Lambertian model for smooth materials.To enable deferred shading the team started from the code of Crysis 2.Initially Forward+ rendering with MSAA anti-aliasing was considered, but then the team decided to go with Deferred rendering for most materials and Forward+ only with materials with specific shading requirements like hair and eyes. Forward+ remains an interesting option for future development.Physically Based Shading is very prone to specular aliasing, and that was fixed by applying a variance filter in screen space, that also helps on thin, highly reflective geometry.Unfortunately the filter created noticeable outline artifact. It was partly fixed by reducing specular reflectance for dielectrics, but ultimately the team decided that temporal stability was more relevant than the additional artifacts.Lighting was especially important for the game, and the team implemented a quite complex model:
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