Game Development Reference
In-Depth Information
Aerial Perspectives
Games with party-based or multipresent interaction models need a camera model
that allows the player to see a large part of the game world and several different
characters or units at once. Normally such games use an aerial perspective, which
gives priority to the game world in general rather than to one particular character.
In games with multipresent interaction models, you must provide a way for the
player to scroll the main game view around to see any part of the world that he
wants (although parts of it may be hidden by the
fog of war
; see Chapter 14,
“Strategy Games”). With party-based interaction models, you may reasonably
restrict the player's ability to move the camera so that it cannot move away from
the region of the game world where the party is.
TOP-DOWN PERSPECTIVE
The
top-down perspective
shows the game world from directly overhead with the
camera pointing straight down. In this respect, it resembles a map, so players find
the display familiar. It's easy to implement using 2D graphics, which keeps its use
common on smaller devices, but its many disadvantages have led designers to use
other methods on more powerful machines.
For one thing, this perspective enables the player to see only the roofs of buildings
and the tops of people's heads. To give a slightly better sense of what a building
looks like, artists often draw them
cheated
—that is, at a slight angle even though
that isn't how buildings appear from directly above (see Figure 18.1).
The top-down perspective also distances the player from the events below. He feels
remote from the action and less attached to its outcomes. It makes a game world
feel like a simulation rather than a place that could be real.
Designers of computer and console games now usually reserve this perspective for
showing maps, although it is still common on smaller devices and some web-based
games.
Flight Control
, for example, is a hugely popular top-down game for the iPhone.
ISOMETRIC PERSPECTIVE
The isometric perspective is normally used to display 2D outdoor scenes. While the
top-down perspective looks straight down at the landscape from an elevated posi-
tion, the isometric perspective looks across the landscape from a somewhat lower
elevation, with the camera tilted down about 30 degrees from the horizontal. If the
game world is rectilinear, as they usually are in games that use the isometric perspec-
tive, the camera is normally positioned at a 45-degree angle from the north-south
axis of the landscape. This permits players to see the sides of buildings in the land-
scape, as well as the roof. See Figure 4.5 for a typical example. In the main view, a
mixed troop of soldiers marches out through a gap in a city wall. You can see two
sides and the roofs of various buildings around the soldiers.
