Parallax scrolling

related topics
{system, computer, user}
{@card@, make, design}
{game, team, player}
{math, energy, light}
{film, series, show}
{ship, engine, design}
{math, number, function}

Parallax scrolling is a special scrolling technique in computer graphics, first popularized in the 1982 arcade game Moon Patrol.[1] In this pseudo-3D technique, background images move by the "camera" slower than foreground images, creating an illusion of depth in a 2D video game and adding to the immersion.[2] The technique grew out of the multiplane camera technique used in traditional animation since the 1940s.[3]

Contents

Methods

There are four main methods of parallax scrolling used in titles for video game console systems.

The layer method

Some display systems support multiple background layers that can be scrolled independently in horizontal and vertical directions and composited on one another. On such a display system, a game can produce parallax by simply changing each layer's position by a different amount in the same direction. Layers that move more quickly are perceived to be closer to the virtual camera. Layers can be placed in front of the playfield—the layer containing the objects with which the player interacts—for various reasons such as to provide increased dimension, obscure some of the action of the game, or distract the player.

The sprite method

Programmers may also make pseudo-layers of sprites—individually controllable moving objects drawn by hardware on top of or behind the layers—if they are available on the display system. For instance Star Force, an overhead-view vertically scrolling shooter for NES, used this for its starfield, and Final Fight for the Super NES used this technique for the layer immediately in front of the main playfield.

The repeating pattern/animation method

Scrolling displays built up of individual tiles can be made to 'float' over a repeating background layer by animating the individual tiles' bitmaps in order to portray the parallax effect. This software effect gives the illusion of another (hardware) layer. Many games used this technique for a scrolling star-field, but sometimes a more intricate or multi-directional effect is achieved, such as in the game Parallax by Sensible Software.

The raster method

In raster graphics, the lines of pixels in an image are typically composited and refreshed in top-to-bottom order with a slight delay (called the horizontal blanking interval) between drawing one line and drawing the next line. Games designed for older graphical chipsets—such as those of the third and fourth generations of video game consoles, those of dedicated TV games, or those of similar handheld systems—take advantage of the raster characteristics to create the illusion of more layers.

Full article ▸

related documents
Highcolor
Eurocard (printed circuit board)
Tablet PC
Refreshable Braille display
Bit blit
Wikipedia:How to reduce colors for saving a JPEG as PNG
Power Mac G4 Cube
Fairchild Channel F
Graphics tablet
Williams tube
Connection Machine
5ESS switch
Distributed switching
Physical Layer
Signal generator
UAE (emulator)
Carrier sense multiple access
Automatic call distributor
Sendmail
Insertion loss
Amiga Advanced Graphics Architecture
PalmPilot
Wireless community network
Digital compositing
V5 interface
Bit stuffing
Java Platform, Enterprise Edition
Audio editing
Corel Ventura
Location-based service