I decided to commit a lot more in this case and try to really finish and polish it. So far the project was only supposed to be a playground for WebGL experimentation.
There is now a Java project which will at some point offer server side functionality. So far the project can not be built, though ... I just wanted to have a rough structure in place.
It will take some time until I figure out how to bring the technologies together (Ivy, Spring ... probably Jenkins and connections to a database for file storage - maybe CouchDB).
Currently I am working on the client side, though and that probably will not change for quite some time.
The latest big change was trying to move the map / image creation into a gamestate object in order to handle the process asynchronously.
Unfortunately I do not know enough about the lifecycle of those processes and have yet to really think the mechanism through.
What I have right now works mostly in Chrome and sometimes in Firefox (again!) ... but I am not even sure if it works correctly at all.
The loading information is shown, the mouse pointer does not say "busy", but the text can not be selected, so I guess something is still blocking.
Pretty often Firefox blocks everything for almost the entire loading process ...
Maybe looking into Closures can help with figuring out what I am doing and what I should be doing.
I asked the question on StackExchange:
A feeling tells me that the process is called asynchronously but still blocks everything, because the CPU works on the new process exclusively.
Maybe I have to use several setTimeout calls in order to free CPU resources (so that the tab / browser is never blocked)!?