Nvidia GeForce GTX 980 White Paper page 20

MAXWELL: ENABLING THE NEXT
GeForce GTX 980 Whitepaper FRONTIER IN PC GRAPHICS
We also use the same approach to quickly compute diffuse or specular lighting with only a few scattered
cones. Ultimately as a result, we're able to compute approximate GI at high frame rates in real time,
allowing us to realistically render glossy and metallic surfaces.
Figure 10: In the example above voxel cones are used to produce various forms of diffuse and specular light
20