
44 I Geometry Manipulation
(a) (b)
Figure 3.4. Horizon views. (a) A hole at the north pole. (b) The filled hole.
Compared to geometric solutions, our screen-space approach has excellent vi-
sual quality with no tessellation or geometric cracking artifacts, uses very little
memory, and is light on the CPU, requiring only the bounding rectangle compu-
tations, culling, and two draw calls. However, its fragment load can be higher
given that many fragments are discarded from extreme horizon views,
2
early-z
and hierarchical-z are disabled due to using
discard, and that a ray/fragment in-
tersection test is used. Given the speed difference between JavaScript and ...