The massive scale of such games presents unique challenges to the lighting process.
ARM subsidiary Enlighten has made a significant enhancement to its real-time global illumination software for gaming, making it possible to extend the benefits of immediate illumination to open world games, the fast-growing category of games with massive “geographic” scale.
Open world games are increasing in popularity. Game vendor Ubisoft says in 2014 open world games represented 30% of industry revenue from PC and console games. Ubisoft also says the category has doubled in revenue since 2008. In 2014 five of the top ten best selling games were open world. Open world games are also increasing in game-scale size. For example, Skyrim, from 2011, covers a gaming world of 39 square kilometers; The Witcher 3, from 2015, covers 136 square kilometers. The more landscape, the longer the process of preparing the lighting.
Traditional methods of applying lighting to games—pre-rendered scenes “baked” into the software— become challenging when large open worlds are created in which a player can wander at random. “Dynamic lighting effects are desired,” says Chris Porthouse, VP of gaming middleware for Enlighten. “But the performance cost of traditional methods is too high.”
Using Enlighten to create real-time lighting in an open world game starts as it does with any game. The software precomputes the location of static geometry in every scene, and stores the relevant global illumination data. Everything else, such as characters and randomly introduced lighting issues from game play, is calculated at run-time. Enlighten computes the required indirect lighting output (light maps, light probes, and reflection captures) in real time.
Porthouse says real-time global illumination offers an improved workflow, which lowers production costs. “Our customers often license Enlighten for workflow, not just for artistic quality,” says Porthouse. “Otherwise it is a very manual operation with much waiting for baking and resetting. It is a long iterative process.” Enlighten claims their global illumination technology offers a 50% performance improvement over traditional scene-based lighting technologies. “Outdoor environments or indoor scenes, it doesn’t matter,” says Porthouse. “Because it is an infinite bounce solution, we get better detail.”
Geomerics says specific improvements in Enlighten allow:
- 50% better performance dynamic global illumination in open world games;
- Large-scale lighting effects (such as time of day) now possible at high quality;
- Natural results even in problem areas (high verticality or occlusions such as gorges);
- Continuous traversal from indoors to outdoors with consistent global illumination;
The result, Porthouse says, is “one real-time lighting solution for all scenes.”
Enlighten runs separately from the rendering thread, which Porthouse says makes it a good technology for creating virtual reality content. “Enlighten can run in the background at 10-20 frames per second; for VR it is the only game in town.”