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OPM: What is ray tracing and how will it
change how we experience games?
Tomasz Szałkowski: Ray tracing is a
technique for achieving photorealistic
graphical effects (and other effects,
such as realistic audio) which require
information gathered from a scene’s
geometry. It works based on the ability
to determine the intersect point of a
ray cast in any given direction from any
given point in a 3D scene represented in
a search-optimised form. This technique
can be mixed in with any of the other,
already-existing algorithms and effects.
With modern hardware, ray tracing can
even completely replace rasterisation
in less complicated scenes or effect
sequences. There hasn’t been a new
technology this hot in a long time; the
interest in ray tracing and the pace of
software adaptation is unprecedented.
Currently, the most popular approach
is a hybrid one, using rasterisation plus
ray tracing. This approach does not cut
off users without the required hardware
and allows for the relatively smooth
transition of individual elements of
an engine to the new technology. For
upcoming titles, this means increased
realism in terms of lighting, shadows
and object surfaces, as well as better
audio and even AI algorithms.
OPM: Is there something in Dying Light
2 that will benefit from ray tracing?
TS: Dying Light 2 is the largest game
created using our in-house C-engine. It
is very important for us to achieve our
ambitions in terms of graphics, which
is why this will be the first Techland
production to support ray tracing. We
are implementing it in cooperation with
Nvidia [on PC] and using the latest
achievements in this domain. Thanks to
this technology, our shadows in sunny
weather look like they really would
(among other reasons, because they take
into account the size of the sun in the
sky). Ambient occlusion effects have
gained spatial stability and no longer
suffer from compromises tied to the
specifics of effects affecting screen space
(they operate only on what is visible
on the screen, meaning the floor under
a table doesn’t affect the displayed
image when we look down at the table
top). Dark Zones are an important
element of our game, which is why
we are experimenting with secondary
illumination (reflected off surfaces)
from artificial light sources (such as the
player’s flashlight), which will make the
experience of exploring these regions
even more intense. As we experiment
with this new technology, we can’t help
but want to keep trying new effects or
change existing ones, so this list might
yet change.OPM: Can this be added to older games
running on new hardware?
TS: Definitely. Most of the work is tied
to creating and updating scenes for the
needs of raytracing. Then that scene can
be used in multiple passes, achieving
different effects.OPM: Is this something only large
studios can make use of?
TS: This technology is available to
anyone with the right hardware. In the
near future, that will no longer be a
barrier. This year AMD cards supporting
ray tracing will be available and we also
expect the next generation of RTX cards
from Nvidia to come out. I think Intel
will join that club as well and the new
generation of consoles will also support
ray tracing. Widely available engines
already support ray tracing, so everyone
can try it out.
Small projects even have a certain
advantage: thanks to the lower
complexity of their scene, they can
use ray tracing to a greater degree than
complicated open-world Triple-A games.OPM: Is there a downside to using ray
tracing? Will it harm framerates?
TS: I wouldn’t look at ray tracing as
an element that causes performance
problems. This is a technology, an API,
part of DX12. Effects built off the use
of ray tracing might be computationally
intense in the very nature of the effect;
for example, gathering light coming from
all directions around a pixel is a very
heavy task if you take a straightforward
approach. You need to use well-known
optimisation tricks and develop new
ones. Invest in what pays off. Like
everything new, with ray tracing it will
take time for everyone to learn how to
use it effectively. It was the same with
every advance in the world of graphics
where mature technology would often
be placed in direct comparison with
new technology. The success of that
new technology drives the research that
goes into new hardware generations. I
think in a few years, ray tracing will be
something completely standard.With ray tracing making headlines we chat to
Tomasz Szałkowski, Techland’s rendering
director, on what it means for the future of gamesRAY OF LIGHT
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