Re: update / new features

On 7/29/2026 4:42 PM, Jim Diamond via ntg-context wrote:
> On Wed, Jul 29, 2026 at 13:57 (+0200), Jean-Pierre Delange via ntg-context wrote:
> 
>> 2.
> 
>> One internal cross-reference remains unresolved in the 3D document.
> 
> I notice that luametafun-threed.tex has
>          reference=fig:threed:process:2,
> *twice*, once on like 513 and once on line 524.
> 
> I'd hate to go out on a limb and say this is the problem, but I'm
> suspicious.  :-)

indeed, so now that you joined the testing:

\startMPpage
lmt_scene_start [
     width        = 10cm,
     resolution   = 150,
     supersample  = 2,
     crop         = true,
     projection   = "perspective",
     light        = (0,-1,-2),
     eye          = (20,20,20),
     target       = (0,0,0),
     up           = (0,0,1),
     intensity    = 1.1,
     cache        = true,
     name         = "example",
] ;

lmt_scene_material [
     name      = "surface",
     diffuse   = (.9,.6,.2),
     specular  = (.5,.5,.5),
     shininess = 25,
     opacity   = 1,
     ambient   = .25,
] ;

lmt_scene_implicit [
     id       = "chmutov",
     code     = "32*(x*x*x*x*x*x + y*y*y*y*y*y + z*z*z*z*z*z) - 
48*(x*x*x*x + y*y*y*y + z*z*z*z) + 18*(x*x + y*y + z*z) - 3",
     dfdx     = "192*x*x*x*x*x - 192*x*x*x + 36*x",
     dfdy     = "192*y*y*y*y*y - 192*y*y*y + 36*y",
     dfdz     = "192*z*z*z*z*z - 192*z*z*z + 36*z",
     xmin     = -1.3,
     xmax     =  1.3,
     ymin     = -1.3,
     ymax     =  1.3,
     zmin     = -1.3,
     zmax     =  1.3,
     nx       = 150,
     ny       = 150,
     nz       = 150,
     material = "surface",
     normal   = "smooth",
] ;

lmt_scene_stop ;

\stopMPpage

Needs 6.277 for the initial run (5.866 metapost) .. only a million 
triangles and three times that on vertices. Kind of deep nested 
z-buffering here (some 1100 x 1100 pixels downsampled to 550x550 anti 
aliased). I bet that on this silicon graphics machine of your past it 
took more time but maybe not.

Hans

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                                           Hans Hagen | PRAGMA ADE
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