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FlightGear Newsletter April 2014: Difference between revisions
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== Scenery corner == | == Scenery corner == | ||
=== The Making of a new World Scenery === | |||
A frequently asked question about scenery is: "Why isn't the terrain updated more often?". Most of us are probably unaware about what is required to build a new World Scenery and what is required to ship a complete set of data for rendering the world in FlightGear. As there is actually a new build in progress, we are able to present some naked numbers to give a rough impression about the resources involved. | |||
First, there is the raw data. Roughly half a dozen databases containing more than 100GB of elevation, coast lines, water ways, roads, land cover, navigation data and all the things that make up the details of our planets surface. [[File:terrain-generation-memory-consumption.png|right|thumb|Memory consumption during scenery creation]] | |||
All these information have to be converted into files understandable by FlightGear. The earth's surface in FlightGear is cut into tiles, each tile containing a 3d model for that area. While generating a single tile is a not too complicated task, generating the entire world is. Roads, coastlines, run- and taxiways do sometimes cross tile boundaries so the 3d surface has to be sliced at the tile boundary. The vertices on both edges have to be at the exact same position. To guarantee, you can't fall into the abyss while taxiing across an unclosed tile boundary, all tiles have to be created in a single run with the current toolchain. | |||
The machine performing that task has to crunch all the 100GB of raw data, keep the results more or less in memory and write the results to disk. This is an extremly time and resource hungry job. The current vectorization job has been started on Feb. 28th and is still running (Apr. 6th). Probably most impressive is the memory consumption which has grown to nearly 130GB. This is RAM, not Harddisk. As the machine is unfortunately ''only'' equipped with 100GB of RAM has started to use nearly 30GB of swap space. | |||
All this only works because of just a few people working hard and usually undiscovered in the background. | |||
=== Airports === | === Airports === | ||