Graphics Reference
In-Depth Information
Roughness = 0
Roughness = 0.25
Roughness = 0.4
Figure 4.28.
Another example of Hi-Z Screen-Space Cone Tracing producing spread
reflections the farther it travels due to micro fracture simulation using material rough-
ness.
levels. While the algorithm works well for local reflections, there are some edge
cases where it may fail because of insucient information on the screen. This
algorithm can only reflect what the original input image has, as we have seen.
You will not be able to look at yourself in the mirror since that information is
not available to us in screen space. Hi-Z Screen-Space Cone Tracing is more of
a supplementary effect for dynamic reflections in dynamic 3D scenes with the
cheap glossy appearance on them, and it's recommended that you combine it
with other types of reflection techniques such as local box projected [Behc 10]
or sphere projected [Bjorke 07] cube-maps to take over when Hi-Z Screen-Space
Cone Tracing fails as a backup plan. Hi-Z Screen-Space Cone Tracing should
not be used on its own as a single solution because of the inherent problems the
screen-space algorithm has, unless you have a very specific controlled scene with
a specific camera angle where you can avoid the problems to begin with, such as
flat walls and no mirrors, etc. The glossy reflections help hide artifacts that are
otherwise visible as mirror reflections.
4.11 Future Work
The system could be extended in many ways. One idea is to take a screenshot
of a 3D scene and store the color and depth information in conjunction with the
camera basis. With this we could at run time re-project this local screenshot
without any dynamic objects obscuring interesting information from us. The
screenshots would act like local reflection probes, and we would pick the closest
interesting one and do our Hi-Z traversal.
The Hi-Z Screen-Space Cone-Tracing technique could also be applied on cube-
maps, where we construct a cube-mapped Hi-Z acceleration structure and ray-
