Re: [grt-talk] Rotate-bug and normal (?) accuracy problem

[Simon Adameit]

Nikodemus Siivola wrote:
> When rotating (at least around Y-axis) a rotation of 90 or 270 degrees
> causes wierd things to happen. This applies to both spheres and boxes, so
> it seems to be a problem with the transformation, but something
> *especially* funky seem to be going on with boxes...

Very strange, indeed...

> Also, when camera is farther away spheres seem to be suffering from a
> accuracy problem, probably due to normals, but the surface shadowing itself
> is also a possibility. Or maybe we a missing the first surface. I doubt the
> last one, though.

And I doubt the first one.
In trace.lisp replace local-model with this to see why:

(defun local-model (ray scene)
 (let*((n (ray-hit-normal ray))
       (r (x n))
       (g (y n))
       (b (z n)))
   (rgb r g b)))

This also shows the problem with the box edges.