Abstract: A method is provided to update information in a computer system comprising providing a reactive value hierarchy structure in a non-transitory computer readable storage device; in response to a change in a reactive value corresponding to a node in the hierarchy, marking nodes within the hierarchy that share as dirty a path with a node corresponding to a changed reactive value; traversing down through the hierarchy to a level where a reactive value is located that is either dirty or clean; if the reactive value is dirty, traversing back up to a dependent node in the hierarchy and compute a new reactive value and repeating the traversing down step; if the reactive value is clean, traversing back up to a dependent node and repeating the traversing down step; and producing at least one side-effect in the computer system in response to a compute of a new reactive value.

Abstract: The present invention provides a method, system, and computer program product for managing terrain rendering information. The terrain rendering information includes a data structure of render blocks. The data structure represents a three-dimensional terrain topology of a virtual world with a set of two-dimensional terrain topologies. Each render block includes primitives that define samples of a respective area of terrain to be rendered. A render block manager manages the allocation of render blocks in the data structure based on current reference point information and allocation criteria. Terrain data at higher levels of detail (that is, a greater resolution) is kept closer to the reference point information by adding and removing appropriate render blocks. In this way, appropriate terrain rendering information is maintained efficiently in the data structure during movement of a reference point.