Remedy has worked on the Microsoft DirectX Raytracing (DXR) API that allows them to get more accurate and precise results for lighting and ambient occlusion on modern GPUs. If this works, it can be the next step forward for lighting solutions, however, it is still a costly solution for now. Ray tracing itself is technically not a new thing, but given how real-time raytracing is computationally expensive, it hasn’t been utilized in the development process of existing games.
We had the chance to attend a keynote by Remedy at Devcom. Here are some of the key points from the presentation.
- Raytraced shadows are precise and have more info that allows for better visual accuracy
- Performance cost on a single TitanV GPU at 1080p is 5ms for AO and 4ms for shadows.
- The caveat of using rays per pixel for reflections is shimmering artefacts.
- Remedy recommends using +3 rays on bright pixels.
- The biggest optimization work was done when they split ray casting and shading. It reduced more than half of the cost of reflections for the Northlight engine.
- Remedy has already used indirect diffuse lighting for Quantum Break on consoles, and they are also likely to use the same lighting system console versions of Control.
- According to Remedy, the raytraced solution gets rid of the staircase effect often seen in games
You can read more about devcom including our coverage of the Making of God of War keynote from Cory Barlog. It gave us our first look at behind the scenes development issues and concept made by the team for this new game.