This technical report extends the content of [JZJ∗ 15], by adding some additional explanations and details, and including new tests with more complex multilayered materials.

In this work we introduce a set of techniques for real-time ambient occlusion targeted to very tight budgets. We propose GTAO, a new formulation of screen-space ambient occlusion that allows the composited occluded illumination to match the ground truth reference in half a millisecond on current console hardware.

Transparencies have always been a tricky problem for games, to render them correctly you have to draw them in front-to-back order from the view of the camera, traditionally this means to sort them when you do this you have to break apart material batches and sometimes even meshes, which affects performance.

Ambient occlusion is ubiquitous in games and other real-time applications to approximate global illumination effects.