Action Games - Fundamentals of Game Design - page 412

model makes less sense. Tet r is , for example, uses a puzzle-manipulation model.
Lemmings uses an omnipresent model; the player may click any lemming at any time.
The nature of the actions you choose to include will tend to dictate your interac-
tion model. Ask yourself what the player is going to do, and that will tell you how
she should do it.
Camera Models
Because the player must see and react to events so quickly in action games, the
choice of camera model is critical. We'll look first at the distinction between 2D
and 3D games and then at the choices available in 3D games.
2D CAMERA MODELS
Two - dimensional ac tion games t y pically use one of t wo camera models : a side v iew
or a top-down view. Tet r is uses a side view; Robotron: 2084 uses a top view of the
playfield, although the characters themselves are displayed side-on. If the side view
can scroll long distances to the left and right, this is known as side-scrolling and is
classic for avatar-based games from Defender to Kung Fu Panda . Top-down views
sometimes scroll long distances from the top to the bottom of the screen as the
avatar moves forward through an environment; this is known as top-scrolling and is
best known in flying games like Xevious . Gauntlet has a top-down view that scrolls
in all four directions.
You may also design your game so that it scrolls continuously at a fixed rate from
top to bottom or right to left; this is called continuous scrolling . It puts more pressure
on the player because she cannot stop it; she can only deal with challenges as they
come. Var iable scrolling causes the landscape to scroll under, or behind, the avatar
in direct response to the player's actions; if the avatar turns around and goes in the
opposite direction, the view duly scrolls back again. In effect, it lets the player run
away from enemies and perhaps even take a break.
Continuous scrolling and variable scrolling have a direct effect on the gameplay,
because the latter allows the player to control the pace at which he faces enemies,
whereas the former does not. You may also encounter another term, parallax scroll-
ing , which is a cosmetic display technique with no actual effect on the gameplay.
Parallax scrolling creates a slight illusion of three dimensions in a two-dimensional
environment by having objects that are designated as being in the background
scroll by more slowly than the ones in the foreground. This gives the impression
that the background objects are farther away.
3D FIRST PERSON
In games set in a 3D space, the perspective is most often, but not always, closely
tied to an avatar with either a first-person or a third-person point of view. The first-
person perspective is particularly successful for high-speed 3D shooting games such