Graphics Reference
In-Depth Information
II
Lighting and Shading
We've seen a great jump in the quality of game lighting in recent years. In
a natural progression from per-vertex shaded triangles through simple per-pixel
Phong of the first GPUs we entered the era of highly customized energy preserving
lighting models. The new lighting models offer greater realism expected from the
games on the new generation consoles, while allowing the artists much simpler
control, enabling them to effectively produce the incredible amount of assets
required for the new games.
The chapter “Physically Based Area Lights” by Michal Drobot discusses
the lighting approach used in the Playstation 4 exclusive launch title
Killzone:
Shadow Fall
from Guerrilla Games. We went beyond the energy preserving model
implementation and focused on accurate area light representation needed, for ex-
ample, for realistic specular reflections of the Sun. Area lights are almost a
necessity for effective work with the new energy preserving lighting models, as
these don't allow artists to fake bright and wide specular lobes any more.
The section also includes two chapters about volumetric lighting. “High Per-
formance Outdoor Light Scattering Using Epipolar Sampling” by Egor Yusov
describes the ecient solution for rendering large scale Sun-lit atmosphere. The
author uses epipolar sampling and 1D min-max shadow maps to accelerate the
rendering process.
“Volumetric Light Effects in
Killzone: Shadow Fall
” by Nathan Vos focuses
on the practical solutions to the in-game rendering of volumetrics from both
local lights and sunlight. He offers several methods for both speed and quality
improvements of the volumetrics as well as solutions for combining volumetric
effects with other transparencies in the scene.
The next chapter, “Hi-Z Screen-Space Cone-Traced Reflections,” by Yasin
Uludag describes the fast screen-space real-time reflections system used in the
new
Mirror's Edge
game. Yasin uses ideas from cone tracing to produce plausible
reflections for any surface roughness as well as hierarchical Z-buffer to accelerate
the ray marching pass.
“TressFX: Advanced Real-Time Hair Rendering” by Timothy Martin, Wolf-
gang Engel, Nicolas Thibieroz, Jason Yang, and Jason Lacroix discusses tech-
niques used for hair rendering in the
Tomb Raider
. The authors cover individual
conservative hair rasterization and antialiasing, transparency sorting using linked
lists, as well as lighting and shadowing of the hair volume.
