5.2.2 Real-time solver
The real-time module is present in the editor and the game. It generates light maps and probes for direct feedback of indirect lighting.
The real-time solver is split into the following stages:
The input lighting stage calculates how lights illuminate the
clusters, including dynamic lights. The light values are added together for all
lights, and the final value is multiplied by the albedo of the cluster. This is
based on the material of the geometry that the cluster is made of. Realistic
rendering of lights always requires shadows and this applies to the input
lighting as well. Directional lights can correctly handle shadowing, that is,
clusters that are in the shadow area of the light do not receive any light.
Enlighten supports shadowed spot lights and point lights as well, but this is
not implemented in Unity 5. For this reason, set an appropriate range for both
spot and point lights to avoid light leaking of the indirect light.
The solve stage sums up the cluster value multiplied by the stored
form-factors, and stores the results in the light map. The run-time performance
is therefore directly linked to the number of form-factors stored per pixel or
The bounce stage reads back the values from the light maps and
bounces light values back to the clusters. This way Enlighten properly simulates
multiple light bounces. In real-life the bounce happens at the speed of light,
but it is limited to the light map update rate in Enlighten. This is typically
limited by the render update rate.
Lights, materials and the pre-compute data are inputs to this step and
some of these can be changed at run-time. This enables you to fine-tune the lighting and
the appearance of the scene with instant feedback.