Killer Game Programming in Java

Accelerating Terrain Following

The code for terrain following sacrifices accuracy for speed, meaning that users can move quickly over the terrain with the disadvantage that they move straight into the side of a mountain or float off the edge of a cliff. Their vertical position will be corrected, but a temporary position disparity is disconcerting. What can be done? A number of tricks can be utilized without making any fundamental changes to the application.

The step distance used in KeyBehavior is 0.2 world units, which is 26 terrain units (0.2/0.0078125). As a rough comparison, each mesh coordinate is 30 units apart. If the step distance was reduced, the user would move over the terrain more slowly, and height changes would occur more gradually. This would help the picking code keep up with the height adjustments.

It's possible to increase the user's height, which is 0.5 world unit in KeyBehavior or is 64 terrain units. If the eyeline is higher off the floor, then a larger height change will be required before the users notice that they've sunk beneath the surface.

Two other solutions are to create landscapes with gentler slopes and make it impossible for users to move into rough terrain by imposing restrictions on KeyBehavior. This latter kind of behavior is typical of racing games, where a vehicle can only move a short distance off the racing track.

The terrain and scenery (the 3D and 2D ground cover) are different. Even when the terrain is flat, the problem of walking through castle ...