Game Development Reference
In-Depth Information
side-scrolling
Side-scrolling games are viewed from the side, and players can pan back and forth.
A good example is
Angry Birds.
This type of game occasionally adds parallax scroll-
ing to give a greater sense of depth. A few games, such as
Fly Hard
and
Shmusicup,
use this same design approach but scroll vertically instead of horizontally.
Scrollers can support games that call for exploration but also allow for rapid
action. These types of games are often referred to as
platform
games.
in parallax scrolling,
foreground elements
move faster than
those in the back-
ground to add to the
illusion of depth.
Faux 3D Backgrounds
Scroller games are
popular, as you can
see in racing games
like
Mario Kart
, beat
'em up games like
the simpsons
, and
platformers like
super Mario Bros.
Designers are able to combine the top-down and side views into a faux 3D type
of environment using a projection. These aren't true 3D worlds. Instead, they
use 2D graphics (sprites and tileable pieces) to give the impression of a more
dimensional world, but the computer doesn't have to scale the 2D sprites or tiled
elements used to create the backgrounds.
This approach was excellent in earlier games (
DOOM, Duke Nukem 3D)
because
the machines that ran the games didn't have the computing power of most systems
available today. In those early games, the engine used to run the game created the
world on a two-dimensional grid using closed 2D shapes called
sectors
and then
added structures as flat, simple objects that were the
sprites.
Today's systems can run true 3D and allow the gamer to move throughout a
more realistic world; however, faux 3D (or 2.5D) backgrounds are still used in
some games. For the purpose of discussing faux 3D backgrounds in this chapter,
the topic is being limited to creating the graphics for the environments.
2.5 D refers to either
A
sprite
is a graphic
object with its own z
plane, which allows
it to appear in front
of or behind other
objects. it can move,
but it doesn't have to.
Pseudo (fake) 3D used for games like
Baldur's Gate
3D games that are played entirely in 2D, such as
Pandemonium
and
Clockwork Knight
Let's take a step back and review what we know about creating the illusion of
depth. Perspective is used in a drawing or painting to create a believable environ-
ment (depth). This sense of depth is accomplished by having a horizon line and
vanishing points. Figure 5.7 shows how two points fixed on a horizon line can be
used to draw shapes with correct perspective.
Projections are a bit different. A sense of depth is created, but there are no dis-
cernible vanishing points. With parallel projection (also known as
axonometric
projection
), unlike top-down or side views, the graphics are rotated slightly to
reveal other facets, thereby creating a faux 3D image.
in an axonometric
projection, there
are no discernible
vanishing points,
and the scale for
all objects remains
the same whether
they're in the
foreground or the
distance.
