O3DECon 2021

Implementing global illumination for games at scale (on mobile devices and up to high end PCs) is a hard problem. O3DE currently uses DDGI as a solution to provide both baked and real-time global illumination. However several key issues need to be addressed before this system is ready for production. In this talk I want to address those issues: * Scalability and streaming * Authoring with small or thin objects * Probe aliasing * Volume overlaps and blending * Baking large scenes * Strange mixtures of baked and real-time probe based volumes * Baked lighting variants for day-night cycles or similar setups * Re-using visibility buffers for other effects * Going beyond diffuse GI The idea is to highlight each issue, present a small solution (not necessarily "the" solution) based off experience from developing similar volume based GI systems in other engines, and make more people from the community - both artists and programmers - aware of these issues so we can collectively come up with a proper system that has an easy workflow and provides great results when computing GI for a project. The talk will close with an outlook to some experiments, novel workflows and how the same system could be used to provide GI for large open worlds, maybe even on mobile devices.