When Fortnite first appeared on iPhone, we were quick to laud a genuine technological achievement – a visually cut-down version of the full game that was still recognisably Fortnite, that played the same way, that run the same code and allowed users to buddy up with their friends running on console and PC. Recently, Epic took the mobile version of Fortnite to the next level; the latest iOS devices run the game smoothly at 60 frames per second, just like their console equivalents – and the story of how that became possible is absolutely fascinating.
The truth is that aside from minor modifications to unlock the frame-rate and add the option to the game’s menu system, no substantial code revamp was required at all. Fortnite on the latest iPhones runs at 60 frames per second simply by virtue of the new Apple A12 Bionic silicon – or rather its increased power and crucially, its superior thermal performance. Games development in the mobile space has an extra set of considerations for developers – specifically, not overheating the device. Ongoing optimisations have been taking place, however, but the focus there has been on maintaining performance with the additional demands of the game’s many expansions and enhancements.
Based on conversations with Epic Games, last year’s iPhone X can – in theory – run Fortnite at 60 frames per second. According to the developer, per-frame rendering times vary between eight to 16ms. In more complex scenarios it would be tight, but that’s fast enough to hit 60 frames per second for the majority of the game’s duration. However, the reality is that running the last-gen A11 Bionic flat-out would overheat the device, leading to lower CPU and GPU clocks, severely impacted performance and highly compromised battery life. Epic’s solution is simple then – lock to 30fps and in the process give the device the thermal headroom to stay cool enough to run at peak frequencies.
Read more: eurogamer.net