Sascha Ledinsky wrote:

> Hi,
> 
> does anyone know a compile/patch for pov that supports MIP-mapping for
> image-maps or other types of interpolation than bilinear (bicubic would be
> nice).
> Or the other way round: Is there a reason for mip-mapping isn't supported (I
> think every $100 graphics card can do it ;-)


So far, I can only think of one reason: a single pov's ray has no area 
at the intersection.

Using Mip-mapping required to know that area or the four corners of the 
pixel/ray, in order to have the right depth for mip-mapping... 
(sidenote, there might be an additional problem when "once" is not used 
and there is multiple instance of images involved.)


A graphic card can use mip-mapping because it can use 'boxed rays' (but 
they won't do that with reflection on silly surface (only triangles and 
other flat poly) and neither with refraction).

Povray's ray are not that kind of rays.

It might be possible if the code was changed (heavily) so that instead 
of tracing a ray from the camera, an area (a full pixel, defined by 4 
rays) was traced from the camera. But it may generate more problems for 
other things...

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