Game Development Reference
In-Depth Information
crouching
state. (This attribute may affect other mechanics—it could influence how
big a target the crouching figure presents—but the
crouch
mechanic does not imple-
ment those effects itself.) Next, because all actions should be accompanied by
feedback, your
crouch
mechanic lowers the value of a numeric attribute of the ava-
tar that determines how far the avatar's head is above the ground. The graphics
engine detects this and shows the first-person view from a crouching, rather than
an upright, perspective.
ACTIONS ACCOMPANIED BY DATA
More complicated actions may involve manipulation or storage of data that arrives
from the user interface. In such cases, you must create both an event mechanic that
implements the action and an entity that stores the data. The user interface sets the
value of the entity for the mechanic to interpret.
TIP
Implement
actions in the core
mechanics by creating
mechanics that the
user interface can trig-
ger and entities that
the user interface can
supply with data from
the input devices.
Suppose that in our first-person game, the player uses a mouse to control which
direction the avatar faces, and he moves the mouse to the right. This input trans-
lates into an action, causing the avatar to turn to the right. But a mouse is an
analog device, not a binary one like a controller button, so in addition to the infor-
mation that the mouse moved, the UI also sends data about how far it moved. This
event requires a mechanic that must interpret the data and make the appropriate
changes to the avatar's direction-facing attribute.
Entia non sunt multiplicanda praeter necessitatem. (Do not create more entities than
necessary.)
—A
TTRIBUTED TO
W
ILLIAM OF
O
CCAM
Designing the core mechanics consists of identifying the key entities and mechan-
ics in the game and writing specifications to document the nature of the entities
and the functioning of the mechanics. This is the very heart of the game designer's
job, and the more complex the game, the longer it takes—sometimes weeks or
months. Because you can make so many kinds of games, this topic can describe the
process only in general terms. Use your knowledge of existing games and of your
chosen genre to fill in the details.
Reading this chapter alone gives you the tools to document your core mechanics,
but it doesn't contain the information necessary to create a balanced game. Don't
start designing your mechanics until you have also read Chapter 11, “Game
Balancing.”
