Game Development Reference
In-Depth Information
Normally, a 2D display engine draws the isometric perspective using interchange-
able tiles of a fixed size. As a result, the isometric perspective distorts reality
somewhat because objects that are farther from the camera are not smaller on the
screen. However, the camera does not display much of the landscape at one time,
so players don't mind the slight distortion. The player can truck or dolly the cam-
era above the landscape but cannot pan, tilt, or roll it. You can also allow the player
to shift the camera orientation to one of the other ordinal points of the compass to
see other sides of objects in the game world. If you want to provide this feature, the
artists will have to draw four sets of tiles, one for each possible camera orientation.
You can also let the player choose an altitude from which to view the world, but
the artists will have to draw multiple sets of tiles at different scales.
The isometric perspective brings the player closer to the action than the top-down
perspective and allows him to see the sides of buildings as well as the roofs, so the
player feels more involved with the world. It also enables him to see the bodies of
people more clearly. Real-time strategy games and construction and management
simulations, both of which normally use multipresent interaction models, rou-
tinely display the isometric perspective or its modern 3D equivalent, the
free-roaming camera. Some role-playing games that use a party-based interaction
model still employ the isometric perspective (see Figure 15.3).
FREE-ROAMING CAMERA
For aerial perspectives today, designers favor the
free-roaming camera
, a 3D camera
model that evolved from the isometric perspective and is made possible by modern
3D graphics engines. It allows the player considerably more control over the cam-
era; she can crane it to choose a wide or a close-in view; and she can tilt and pan in
any direction at any angle, unlike the fixed camera angle of the isometric perspec-
tive. The free-roaming camera also displays the world in true perspective: Objects
farther away seem smaller. The biggest disadvantage of the free-roaming camera is
that you have to implement all the controls for moving the camera and teach the
player how to use them.
CONTEXT-SENSITIVE CAMERA MODELS
Context-sensitive camera models require 3D graphics and are normally used with
avatar-based or party-based interaction models. In a context-sensitive model, the
camera moves intelligently to follow the action, displaying it from whatever angle
best suits the action at any time. You must define the behavior of the camera for
each location in the game world and for each possible situation in which the avatar
or party may find themselves.
Ico
, an action-adventure game, implements a context-sensitive model, using differ-
ent camera positions in different regions of the world to show off the landscape
and the action to the best advantage. This makes
Ico
an unusually beautiful game
(see Figure 13.7). Context-sensitive models allow the designer to act as a
