Chapter 4 Perspective, Scene Design, and Basic Animation 105
In addition to tracking off screen objects, the computer may also have
to scroll the game frame as the player moves. Scrolling is where the game
frame is moved so the position of the player is always in the visible play area.
It is important to remember that all objects on the game frame remain, even
though they are not visible. See Figure 4-13.
Scrolling can easily be demonstrated using your hand and a textbook.
The textbook is the game frame and your hand is the visible play area. Lay
your hand on the textbook and move the book without moving your hand.
That is how the computer scrolls the larger game frame to present a moving
view in the visible play area.
A 2D character can be made into multiple poses to create a sprite
character set to display the movement animations used in the game. Recall
from Chapter 1 that a sprite is a 2D asset. A sprite character set, then,
is a collection of 2D assets, such as different poses, for a single character. A
sample sprite character set from RPG Maker XP is shown in Figure 4-15.
RPG Maker XP is a game engine for developers creating role-playing games.
Length
Width
Figure 4-14. Flat shapes like those shown above are 2D objects. The have length (X) and width (Y) dimensions only.
N N
S
E
W
Figure 4-15. This goblin avatar has 16 poses to animate walking in four directions (North, South, East, and West).
Sprites traveling in more than four directions need more poses. If the goblin sprite needs to move northeast, a new
animation set for that direction must be created and programmed into the game.