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Video Game Design Composition
At the core of interactivity in a video game is motion.
Motion
is the
change of position of an object over time. The player avatar and other
game objects move or change to create the challenges and goals of the
game. The game artist forms the objects and creates a visual world in
which game events can exist. To make these realistic, the artist must apply
certain elements to make the movement of these objects realistic. To fully
explore how motion is put into a video game, an understanding of six basic
elements of motion is needed. The six elements, which are explained in the
following sections, are:
• persistence;
• perception;
• translation;
• rotation;
• articulation; and
• morphing.
Persistence
The first element of motion is persistence.
Persistence
in its simplest
definition is, to continue to exist. Physicists have formulas to explain
persistence and what type of motion is occurring. Some of the more common
examples are acceleration, velocity, displacement, and vector.
Acceleration is the rate at which an object is speeding up or slowing down.
Velocity is the speed an object is traveling. Displacement describes how much
something has moved. These are all bundled together with vectors. Vectors
are the direction of forces. In a video game the objects, backgrounds, and
characters can all have motion. Each object will have attributes that define how
it can move and what forces act on it.
Acceleration is a positive vector when a car is speeding up, as shown
in Figure 11-1. Acceleration is a negative vector when a car is slowing
down. The velocity vector determines the direction the car is traveling. In a
video game, “vector up” might be moving forward, while “vector down” is
moving backward. The velocity in both cases is the same, but the direction
is different. Displacement vectors are also directional. A car may have driven
a displacement vector of North or South and traveled the same distance for
each trip.
Perception
Perception
is the observation of something, such as motion. Motion is
perceived as movement
relative
to a frame of reference. A person observes
how things are moving relative to
his or her position and motion.
Without a frame of reference,
motion is not perceived.
For example, if you are
traveling in a car and look at a
book on the seat next to you,
Elements of Motion
CHEAT CODE: RELATIVE
Relative means connected to or
dependent on something else.