118 Video Game Design Foundations
Animation
When a character or object moves on the screen, it is said to be
animated. An animation is a series of frames played in sequence with
small differences between each frame. The brain interprets these small
differences as motion. Think of the fl ip cartoons you may have sketched on
the corners of notebook pages. This is a very basic animation.
Static animation is where the object retains its original pose while
moving. An example is a stick fi gure with arms, legs, and head kept in the original
position, but the fi gure moves across the computer screen, Figure 4-34. Since
the arms and legs do not move, the fi gure appears to slide across the screen.
You can try static animation at your desk. Pick up a pencil or pen and hold it in
front of you. Move the pencil up and down while holding it in the original posi-
tion. Hurray! Static animation in practice.
In active animation, an object changes pose while moving on the
screen. An example of this is a stick fi gure with legs that move in a walking
motion to take steps as the fi gure moves across the screen, Figure 4-35.
A B
C D
Figure 4-34. These are frames from a static animation created in Pivot Stickfi gure Animator. Notice that the stick fi gure
moves to a different position without moving arms and legs. The body stays static as it moves.