Game Development Reference
In-Depth Information
In the
contestant
model, the player answers questions and makes decisions, as if a
contestant in a TV game show. Navigation will not be necessary; you will simply
assign different decision options to different buttons.
The
desktop
model mimics a computer (or a real) desktop and is ordinarily found
only in games that represent some kind of office activity, such as business simulations.
A coherent design that follows common industry practice will probably fit into one
of these familiar models. You can create others if your game really requires them,
but if you do so, you may need to design more detailed tutorial levels to teach your
player the controls.
NOTE
The previous
edition of this topic
used the term p
erspec-
tive
for all sorts of
virtual camera behavior.
However, perspective
suggests a fixed point
of view, which is no
longer appropriate for
today's intelligent
virtual cameras. This
edition still uses
perspective
to refer to
certain camera models
that are fixed with
respect to the game
world or the avatar,
such as the top-down
perspective or the first-
person perspective.
Just remember that
a perspective is one
kind of camera model.
Other kinds of camera
models, such as
context-sensitive
cameras, aren't called
perspectives because
the camera's viewpoint
moves around.
Camera Models
Old video games, especially those for personal computers, used to treat the game
screen as if it were a game board in a tabletop game. Today we use a cinematic anal-
ogy and talk about the main view on the screen as if it displayed the output of a
movie camera looking at the game world. This is the source of the terms
virtual
camera
and
camera model
.
To define the camera model, you w ill make a number of design decisions about
how you want the player to view the game world, what the camera focuses on, and
how the camera behaves. Certain camera models work best with particular interac-
tion models; the next few sections introduce the most common camera models and
discuss the appropriate interaction models for them.
FILMMAKING TERMINOLOGY
The game industry has adopted a number of terms from filmmaking to describe certain
kinds of camera movements. When a camera moves forward or back through the envi-
ronment, it is said to
dolly
, as in
the camera dollies to follow the avatar
. When it moves
laterally, as it would to keep the avatar in view in a side-scrolling game, it
trucks
. When
it moves vertically, it
cranes
. When a camera swivels about its vertical axis but does not
move, it
pans
. When it swivels to look up or down, it
tilts
. When it rotates around an
imaginary axis running lengthwise through the lens, it is said to
roll
. Games almost
never roll their cameras except in flight simulators; as in movies, the player normally
expects the horizon to be level.
The 3D Versus 2D Question
A question you must decide early on is whether your game should use a 3D graph-
ics display engine or stick to 2D graphics technology. If a game uses 2D graphics,
the first-person and third-person perspectives will not be available; those camera
models require a 3D engine.
