Lee Elliott wrote: > In a/c that have one or more VC views there's a visible 'jitter' > when looking at parts of the a/c, most notably in my experience, > with the windshield/canopy frames.
This is a bug, not an intentional feature. :) It's a precision problem with the view code. The current architecture puts the coordinate origin at the current tile origin, which is sometimes ~1000m from the viewpoint. So the OpenGL matrix stack has to do something like + move the origin from the viewpoint (where it starts, by definition) to the tile centroid + draw scenery, objects... + move the origin back to the aircraft origin + draw the aircraft, cockpit ... These two matrix multiplications result in floating point values that are "off" by a few parts in 2^23 (basically one part ), due simply to roundoff error in the single precision operations. Doing the math, that comes out to an error of about 1mm. In small cockpits (the A-4 shows this effect really well), that can be several pixels worth of screen. I looked at fixing it about a year or so ago, but got confused and distracted by other things. The best solution would be to "recreate" the cockpit modelview matrix from scratch, using double-precision math for the offsets, instead of deriving it from the tile centroid with OpenGL matrix calls. Andy _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
