The idTech 7 engine has evolved with the arrival of a brand new patch for Doom Eternal, adding ray tracing support for sufficiently equipped PCs – and of course, PlayStation 5 and Xbox Series X, which also receive resolution and 120Hz updates. But it's the RT implementation that's the star of the show, adding beautiful reflections to surfaces like water, glass, metals, plastics and even polished wood. The PC also benefits from Nvidia DLSS support, meaning that even entry-level RT video cards like RTX 2060 can deliver an excellent experience with the next-gen features in play.
So, what's the actual attraction of incorporating RT reflections into a game like Doom Eternal? At default settings, it combines with the standard screen-space reflections to form a 'complete package' for an effect that can have a transformative effect on a game with the kind of materials Doom Eternal uses throughout – shiny metals and plastics – though even rougher materials can still benefit from the effect. Reflections more accurately map to surface types and are far more dynamic, to the point where surrounding, animated environments map perfectly onto the appropriate surfaces – something that standard cube maps can't do.
I was also interested to see that particles are also present in reflections – so sending out a BFG blast into distance, then turning around 180 degrees to look at a glass window would see the effect play out in the reflection, along with other dynamic elements in the scene. And of course, the Doom Slayer himself is present in reflections too – even if it is an approximation. Doom Eternal uses a 'floating hands' approach to the actual first-person model, but the point is that with standard reflections, the player is simply not present at all. Being RT-based, based on the traversal of light rays, even distortions in the material are all accurately mapped – you only get perfect mirror-like reflections if the material itself is perfectly flat. Ray tracing also applies to every pixel, so even tiny glass objects like health flasks will exhibit full RT reflections with pristine detail if you peer at them closely.
