Le 18-09-30 à 23:48, clipka a écrit :
> https://github.com/POV-Ray/povray/releases/tag/v3.8.0-alpha.9861167
> 
> 
> Primary feature of this update is the addition of blue noise dithering.
> 
> Blue noise dithering is a comparatively new ordered dithering algorithm,
> using a tiling pattern to vary the quantization threshold. However,
> unlike the extremely regular pattern used in the otherwise similar Bayer
> dithering, the pattern used in blue noise dithering is constructed to be
> extremely irregular at small scales, while at the same time being
> extremely regular at large scales. In other words, it has a lot of
> high-frequency noise, while at the same time having very little
> low-frequency noise.
> 
> The pattern used by POV-Ray is a hard-coded 64x64 pattern, generated
> using a so-called void-and-cluster approach (utilizing a public domain
> Python script by - as it happens - fellow "Rheinlandian", 3D enthusiast
> and namesake Christoph Peters).
> 
> Due to its high quality and ease of use, blue noise dithering is now the
> default algorithm, and is also used in the preview window, replacing the
> inferior Bayer dithering there.
> 
> 
> The blue noise dithering comes in two variants: Aside from a
> straightforward implementation (`+THbn`) where the threshold of all
> channels is varied according to the same pattern, an experimental
> implementation is available (`+THbnx`) in which the threshold for the
> red and blue channels is varied according to the inverse of the pattern,
> to reduce the noise in the brightness domain (at the cost of more noise
> in the chromaticity domain).
> 
> 
> In the wake of this, ...
> 
> - A couple more error diffusion dithering filters have been added
> (primarily for giggles and because we can). See
> povray.documentation.inbuilt, recent thread "Some stuff related to
> output file formats" for details.
> 
> - The lower limit for the bit depth (previously 5) has been dropped;
> anything between 1 and 16 is fair game now (affects PNG and PPM/PGM
> only; again, mostly for giggles, to better demonstrate dithering, but
> maybe some of you folks may want to experiment with it).
> 
> - Greyscale output no longer forces bit depth to 16 (also primarily for
> dithering demonstration purposes).
> 
> - Greyscale file output now also switches the preview window to greyscale.
> 
> - The `+F` option can now be used to specify both greyscale (`g` suffix)
> and non-default bit depth (numeric suffix) simultaneously. (The `g` must
> come first.)
> 
> - Gamma handling in PGM (greyscale "PPM") files has been changed to be
> consistent with colour PPM.
> 
> - Gamma handling in dithering has been improved.
> 
> 
> I /think/ that's all.
> 

I no longer see the post render info when using isosurfaces with 
improper max_gradient.

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