Killzone: Shadow Fall outputs in native 1080p in single player, but when it comes to multiplayer things get a bit more complicated. Developer Guerrilla Games has explained how it works and why it technically isn't "upscaling", and promised to be more clear in future.
In an FAQ on the game's website, Guerrilla addressed allegations that the game does not run in native 1080p; that it uses upscaling; and that the team had fibbed in the past by describing the game's output as native 1080p with no upscaling.
"Killzone: Shadow Fall's single and multiplayer modes both run at 1080p. In both SP and MP, Killzone: Shadow Fall outputs a full, unscaled 1080p image at up to 60 FPS. Native is often used to indicate images that are not scaled; it is native by that definition," the developer wrote.
However, Guerrilla admitted that by other definitions, multiplayer output is not natively 1080p - it employs a technique called "temporal reprojection", which combines pixels and motion vectors from multiple lower-resolution frames to reconstruct a full 1080p image.
"If native means that every part of the pipeline is 1080p then this technique is not native," Guerilla said, going on to explain its use of the word "native" and apologise for the community's confusion.
"Games often employ different resolutions in different parts of their rendering pipeline. Most games render particles and ambient occlusion at a lower resolution, while some games even do all lighting at a lower resolution. This is generally still called native 1080p. The technique used in Killzone: Shadow FallL goes further and reconstructs half of the pixels from past frames.
"We recognize the community’s degree of investment on this matter, and that the conventional terminology used before may be too vague to effectively convey what’s going on under the hood. As such we will do our best to be more precise with our language in the future."
Click through to the full FAQ for a lengthy technical discussion ot temporal reprojection and how it differs from upscaling.