This function
modifies attributes of vertices in a single
object. The attributes
are properties of each vertex
in a scene; not all are applicable to all objects. In order,
they are: coordinates of the vertex "x", "y", "z"
, color
of the vertex "red", "green", "blue", "alpha"
, normal at the vertex
"nx", "ny", "nz"
, radius of a sphere at the vertex
"radius"
, origin within a texture "ox", "oy"
and
perhaps "oz"
, texture coordinates "ts", "tt"
.
Planes are handled specially. The coefficients a, b, c
in the planes3d
or clipplanes3d
specification are controlled
using "nx", "ny", "nz"
, and d
is handled as
"offset"
. The vertices
argument is interpreted
as the indices of the planes when these attributes are set.
If only one attribute of one vertex is specified, values
may
be given as a vector and will be treated as a one-column matrix. Otherwise
values
must be given as a matrix with ncol(values) == max(length(vertices),
length(attributes))
. The vertices
and attributes
vectors will be recycled to the same length, and entries from column j
of values
will be applied to
vertex vertices[j]
, attribute attributes[j]
.
The value
argument is translated into a row (or two rows if
interp = TRUE
) of values
by finding its location in param
.