Rohan Bernett <rox### [at] yahoocom> wrote:
> NO NO NO! Not mip mapping in POVRay! Mip mapping ruins the image.

  Strange claim.
  Trilinear filtering is closer to the photographic phenomenon than the
plain bilinear filtering. In other words, it's more photorealistic.

  In the real world, when you scan a photograph (or take a photo with a
high-quality digital camera), one pixel will be the average of all the
colors inside the pyramid which goes through that pixel towards the scene.
This is exactly what trilinear filtering simulates: It averages all the
texture pixels which fall into this pyramid to get the pixel color.
  That is, if 40 of the texture pixels are inside that singe image pixel,
the average of all those 40 pixels is calculated there (as would happen
with a photograph).

  In regular bilinear filtering this does not happen. Instead of taking
into account all the 40 texture pixels, it takes 4. All the other 36
texture pixels are simply ignored.
  You can imagine that if the texture has very fine details, this causes
really bad moire effects.

-- 
plane{-x+y,-1pigment{bozo color_map{[0rgb x][1rgb x+y]}turbulence 1}}
sphere{0,2pigment{rgbt 1}interior{media{emission 1density{spherical
density_map{[0rgb 0][.5rgb<1,.5>][1rgb 1]}turbulence.9}}}scale
<1,1,3>hollow}text{ttf"timrom""Warp".1,0translate<-1,-.1,2>}//  - Warp -

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