basemap loaded + displayed

[Patrick Nichols <pnichols@graphics.csail.mit.edu>]

All --

Hit some serious issues today actually displaying the entire basemap + 
route maps, mostly derived from Java serialization issues. I've attached 
an image of the basemap loaded and displayed in a java applet after being 
recursively obtained over RMI - basic b&w for now, will look pretty soon 
(I promise). This at least shows you what the contours look like.

Java RMI note: it turns out that when Java serializes objects, every 
non-transient field of the serialized object is *also* serialized. If a 
Space is serialized, and it has a set of Portals ... which each have a 
pair of Spaces ... which each have a set of Portals ... well, serializing 
a single object requires that the entire graph state be serialized, which 
is bad. This didn't show up for a single loaded building, or even a large 
number of unconnected buildings (remember - the entire connected graph 
only gets serialized, not the entire thing). Java has a hard cap of 15MB 
of serializable state over RMI, causing horrible EOF errors if you try to 
send a huge object over RMI.

Lesson learned: use the transient keyword early and often when writing 
Java RMI code.

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Patrick James Nichols II
Graduate Student, MIT Computer Graphics Group
http://graphics.csail.mit.edu/~pnichols