Avocado: a distributed virtual environment framework

distribution: Because the field values of a compound object completely describes the objects state, the internal representation does not need to be distributed, but can be reconstructed by each process. This can significantly reduce the amount of bandwidth needed to replicate a complex geometric object as only a few field values need to be transmitted instead of a completed geometric description of the object. Local behavior: An objects behavior evaluation ultimately results in one or 5.5. Pacman: A complex distributed application example 125 Fig. 5.17: Original and Fälschung: The Pacman game (right) is loosely based on the ATARI ST game MidiMaze (left), one of the first 3d networked multi-player first-person shooters. The text above the pacman shows user and host name of the controlling process. Fig. 5.18: The pacmans can move freely through the maze and shoot at each other (left). Once hit, a pacman is flatted and disabled for a period of time (right) more field value changes. In a distributed environment the local behavior is only evaluated locally by one process for one object copy and the result is automatically shared via field replication. The result of the behavior is distributed, not the behavior. Distributed behavior: The behavior of the internal representation of an compound object executed at each copy of the object. The behavior evaluation is distributed, not the results. Figure 5.19 shows the node class diagram for the pacman application. The pacman classes are derived from avDCS and represent the different 126 5. Avocado implementation of the distribution architecture