3DISO: Adapting Isometric Scrolling Theory to 3D Worldspace, Part 2

February 7, 2002
by Andrew M. Phelps

Part 1 of this article discussed some of the impetus behind moving our existing isometric engine over to Shockwave 3D, and discussed the basic theory behind scrolling games.

Sample Director 8.5 movie source is available for download in ZIP or SIT archive format (both files are approximately 1.2MB). If you have Shockwave 8.5, you can view the 3DISO engine (~185K).

2 Tile Engines and Scrolling Theory (continued)

2.2 Scrolling in Two Dimensions Simultaneously

Scrolling in two dimensions can, in some sense, be thought of as an extension of single direction character movement, with a mathematical structure of a slightly more rigorous base. Simultaneous scrolling technology has been around for a while now, with classics like Nintendo's Legend of Zelda and Sega's Phantasy Star Series (see figure 7) serving as an impeccable example of the genre. Indeed, most systems to this day operate on the following two principles:

That the data structure that holds the center point stores with it information about the angle the character is heading, and
That the engine has the capability to convert between the local (character) coordinate system and the Cartesian (screen based) coordinates.

Such systems are consistent with the Turtle Graphics methodology developed at MIT under Ableson ^[5], although they can be implemented through a variety of mechanisms.

Andrew (Andy!) is a professor at the Rochester Institute of Technology (RIT) serving in the Dept. of Information Technology, specializing in Multimedia and Web Programming. While completing his MS in Information Technology, he became increasingly interested in multi-user virtual spaces. He is also developing a game programming curriculum, with an emphasis on Lingo based solutions as well as more traditional approaches. Visit his home at andysgi.rit.edu.