Lighting¶

Status: Experimental

present and registered, but lightly documented and not yet covered by dedicated tests.

Description¶

Lighting

A Graphics3D / Plot3D / ParametricPlot3D option controlling surface shading. Lighting -> Automatic (default): per-face Lambertian (flat) shading with a fixed directional light; ambient 0.3, diffuse 0.7. Lighting -> None (or False): disables shading and draws surfaces in their raw PlotStyle/ColorFunction color.

Examples (3)¶

Every input below was run against the current Mathilda build and its output recorded.

Applications (3)¶

An inert option keyword: it just names the left of a rule

In[1]:= Lighting -> None
Out[1]= Lighting -> None

Protected, with no value of its own

In[2]:= MemberQ[Attributes[Lighting], Protected]
Out[2]= True

Accepted by its owning plot builtin

In[3]:= Head[Plot3D[x + y, {x, 0, 1}, {y, 0, 1}, Lighting -> None]]
Out[3]= Graphics3D

Implementation notes¶

Definition. Lighting is an inert option keyword for Graphics3D, Plot3D and ParametricPlot3D: it controls surface shading for 3D graphics; Automatic (the default) is per-face Lambertian shading with a fixed directional light, while None (or False) disables shading and draws the raw PlotStyle/ColorFunction colour. It has no builtin and no OwnValue — only the Protected attribute bit is set on the symbol in graphics_init.c, where its docstring also lives. It is a name, not a value, and exists so that Lighting -> ... can be written in an option list.

Representation. A bare Protected EXPR_SYMBOL. It never evaluates on its own; it is read as the left-hand side of a Lighting -> value rule by the owning plot builtin while it assembles the Graphics3D[...] result, through the shared options plumbing (OptionValue-style lookup). The value on the right is an ordinary expression and is evaluated as usual — so e.g. a colour name on the right reaches the builtin already reduced to its RGBColor[...] literal.

Usage & limits. Meaningful only inside a call to Graphics3D, Plot3D and ParametricPlot3D; elsewhere it is an unused symbol. An unrecognised value is handled (or defaulted) by the owning builtin, not by Lighting itself, which carries no logic of its own.

Attributes: Protected.

References¶

Source: src/graphics/graphics_init.c
Specification index: Mathilda_spec.md

Notes & additional examples¶

Notes¶

Lighting is an inert option keyword for Graphics3D, Plot3D and ParametricPlot3D — surface shading for 3D graphics (Automatic = per-face Lambertian, None/False = flat raw colour). It has no builtin and no own-value; it is Protected and stays symbolic, read only as the left-hand side of a Lighting -> value option rule while the owning builtin builds its Graphics3D[...] result. The right-hand value evaluates normally before the builtin sees it.