- Multiple scattering of sun light in the atmosphere
- Multiple scattering has subtle effect during the day time, but makes the sky look much more natural
- During the twilight, multiple scattering has higher importance (see figures below) add improves realism significantly
- Since sky radiance is pre-computed for all possible locations and directions, this new method do not perform numerical integration of air light integral, but only computes total length of the illuminated ray region and distance to the first lit section. Two look-ups into scattering look-up table are then performed.
- The new shaders compute sun light extinction due to the atmosphere for each vertex of the Earth mesh. They also use pre-computed ambient skylight texture to estimate ambient light for the given sun position
- The sample implements a number of different tone mapping operators that perform better HDR to LDR conversion
This is how twilight sky looks with single scattering only:
Multple scattering makes it look more realistic: