High!

Resuming my long-cherished Khyberspace project, I once more started downloading
SRTM radar elevation data tiles and converting them into PNG 16-bit
heightfields.
For performance reasons, I pre-created the huge mesh2 code to be read in by the
scene script proper (as the mesh2 code is some 120 MB large, I just included
here the PNG heightfield and the mesh2writer script rather than the mesh2
itself).

When I render the scene, two problems occur:

First, between most of the mesh2 triangles, ugly black gaps show up (see
attached image file - no, it's NOT a anti-aliasing issue, the very scene you see
was rendered using +a0.3!). I remember that problem from back in 2005, when I
also tried a Khyberspace scene from SRTM data, and back then, I was told by Mike
Williams (if my notes are right) that it has got something to do with floating
point accuracy. So I got the suggestion to define each vertex of the mesh2 as
close to the origin as possible and then to re-translate the whole mesh.

But when I looked up the old script from 2005, I found that the I wrote back
then was a true Heath Robinson contraption, much too complicated to make use of
it now, so I did not implement Mike William's solution up to now.

The second problem is that whenever I give Earth rotation angles other than 0
(or include the axial tilt), the mesh2 is rotated "out of sight" for the trace()
vector to place the camera on the surface - though in the definition of the
mesh2, all vertices are defined with respect to the origin (as you might look up
in mesh2writer.pov)! So when I try to render such a scene, I just get empty
black space...

Any suggestion how to fix that?

See you in Khyberspace!

Yadgar

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