Hi, Thanks Kelly for the answer. Yes, the map rendering was rewritten a year ago by yours truly and some other Lindens. Quite a few things changed since 2008:
On Tue, Jan 26, 2010 at 8:03 AM, Stickman <stick...@gmail.com> wrote: > --- > 1. The maximum height that the world map captures a region at is > approx. 450 meters up. This means the world map will show anything > below that height, and will not show anything above that height. If > there's a build etc that you do not want showing on the world map > image of the region, its best to build it above 450m (usually 500m or > higher is best). > This is still true. We haven't touched this parameter. > 2. What it captures: Generally the world map will capture an object's > shape and overall color/tint. Details like exact textures on objects > usually aren't captured unless they're of such a large size that they > would take up roughly a quarter of the region or more on their own > (i.e. large enough so that the world map would show the detail of the > texture instead of just the overall color). Most of the time this > translates into roads, tops of buildings, etc. being displayed on the > map. > Incorrect: all textures are assumed to be seen from far above enough as to be average as 1 color, irrespective of their size and scaling. As the goal is to rerender the map for the *whole grid* daily (see below), we cannot fetch and decompress all the full sized textures every day (yikes!). We take full advantage of the jpeg2000 wavelet properties here to read as little as possible and still get a correct average color (modulo Zay's bug apparently). > 3. The world map for a region is updated roughly every two weeks, > which is the length of time for the system to update every region on > the grid once before starting over again. > Incorrect: it's now updated daily. There's a bit of smarts though to avoid rerendering regions that had no change at all. As some smart residents noticed, there is however a delay between texture computation and posting. This is because the map rendering does now something new: it stitches the regions 2x2 and computes sampled zoomed out tiles and repeats that process in a pyramidal scheme all the way out, effectively building a gigantic grid size mipmap. This is what makes the zoom so fast now. Couple of other things new with that map: - it computes only "objects" tiles, no "terrain" tiles: this is to merge the webapp (slurl) map experience and the IW viewer map experience. Also "terrain" was not extremely helpful in heavily built regions. - tiles are stored on Amazon S3, outside the asset server then, reducing load there - IW and webapp use the same tiles : so no more inconsistencies here Back to OObscure original question: would it be possible to get higher res maps for some regions? Hmmm.... From a rendering standpoint, that's easy but that would require a change in the scheme used to store tiles (adding a new layer to the gigantic mipmap) and a change in the viewer code map to get those tiles. We wouldn't do that wholesale though for the whole grid: storing all this data has a cost and we went through quite a bit of computation (balancing cost, speed, usability) before setting on that 256x256 pixels value. Cheers, - Merov
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