Until now, characters in your favorite games have largely featured
totally unrealistic hair, as displaying realistic hair is one of
the most complex and challenging materials to accurately reproduce
in real-time. AMD wants to make the difference with the
introduction of the TressFX technology.
Convincingly recreating a head of lively hair involves drawing tens
of thousands of tiny and individual semi-transparent strands, each
of which casts complex shadows and requires anti-aliasing. Even
more challengingly, these calculations must be updated dozens of
times per second to synchronize with the motion of a character.
Through collaboration between software developers at AMD and
Crystal Dynamics, Tomb Raider features the world?s first real-time
hair rendering technology in a playable game: TressFX Hair.
Lara Croft is an iconic character with an equally iconic ponytail.
AMD says that the TressFX Hair technology revolutionizes Lara
Croft's locks by using the DirectCompute programming language to
unlock the parallel processing capabilities of the Graphics Core
Next architecture, enabling image quality previously restricted to
pre-rendered images. Building on AMD's previous work on Order
Independent Transparency (OIT), this method makes use of Per-Pixel
Linked-List (PPLL) data structures to manage rendering complexity
and memory usage.
DirectCompute is additionally utilized to perform the real-time
physics simulations for TressFX Hair. This physics system treats
each strand of hair as a chain with dozens of links, permitting for
forces like gravity, wind and movement of the head to move and curl
Lara's hair in a realistic fashion. Further, collision detection is
performed to ensure that strands do not pass through one another,
or other solid surfaces such as Lara's head, clothing and body.
Finally, hair styles are simulated by gradually pulling the strands
back towards their original shape after they have moved in response
to an external force.
Graphics cards featuring the Graphics Core Next architecture, like
select AMD Radeon HD 7000 Series, are particularly equipped to
handle these types of tasks, with their combination of fast on-chip
shared memory and massive processing throughput on the order of
trillions of operations per second.