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FlightGear Newsletter September 2012: Difference between revisions
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FlightGear Newsletter September 2012 (view source)
Revision as of 12:18, 13 September 2012
, 13 September 2012→Random Buildings: http://www.mail-archive.com/flightgear-devel@lists.sourceforge.net/msg38307.html and http://flightgear.org/forums/posting.php?mode=quote&f=18&p=166601
(→Scenery corner: Small start on an OSM update, now that the license change is completed. More to follow.) |
m (→Random Buildings: http://www.mail-archive.com/flightgear-devel@lists.sourceforge.net/msg38307.html and http://flightgear.org/forums/posting.php?mode=quote&f=18&p=166601) |
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At KLAX, it's down even further, from 2.7GB to 1.6GB. So far, without any frame-rate impact. | At KLAX, it's down even further, from 2.7GB to 1.6GB. So far, without any frame-rate impact. | ||
This work is now checked into next/master. You'll need an updated simgear and data to see any effect. | |||
Basically, the design has been altered to use a scheme very similar to that of the random trees, where there are a small number of buildings created, and then instantiated multiple times. | |||
The technique relies on a vertex shader, as the final position and rotation of the building are passed in on the gl_Color vector. This in turn has meant that I've been forced to create new version of various vertex shaders. It might be possible to clean that up by having a new parameter to existing shaders indicating that position/rotation information is in gl_Color | |||
There are three known regressions from the previous implementation: | |||
* The reflection map appears to be broken, and is currently switched off. (this might be because the binormal or tangent are not being calculated correctly.) | |||
* The buidings do not cast shadows in Rembrandt, though other objects _do_ cast shadows on the buildings. I don't know the reason for this. | |||
* At high building densities and certain angles of view, one can see gaps in the building placement where the edges of the scenery triangles go. This is unfortunately inevitable, as we have less sizing information during placement. | |||
You should now see significantly lower memory occupancy (500 - 2GB less depending on area and density) when running with random buildings enabled. This will obviously be available in the next FG release as well. | |||
Feedback/comments appreciated as always. | |||
=== Project Rembrandt === | === Project Rembrandt === | ||