rgl (version 1.3.1)

persp3d.triSht: Plot an interp or tripack Delaunay triangulation

Description

The tri.mesh() functions in the interp and tripack packages compute a Delaunay triangulation of a set of points. These functions display it as a surface.

Usage

# S3 method for triSht
plot3d(x, z, ...)
# S3 method for triSht
persp3d(x, z, ..., add = FALSE)
# S3 method for triSht
as.mesh3d(x, z, col = "gray", coords = c("x", "y", "z"), 
    smooth = TRUE, normals = NULL, texcoords = NULL, ...)
# S3 method for tri
plot3d(x, z, ...)
# S3 method for tri
persp3d(x, z, ..., add = FALSE)
# S3 method for tri
as.mesh3d(x, z, col = "gray", coords = c("x", "y", "z"), 
    smooth = TRUE, normals = NULL, texcoords = NULL, ...)

Arguments

x

A "triSht" or "tri" object, produced by the tri.mesh() function in the interp or tripack packages respectively.

z

z coordinate values corresponding to each of the nodes in x.

add

Whether to add surface to existing plot (add = TRUE) or create a new plot (add = FALSE, the default).

col

Colors to apply to each vertex in the triangulation. Will be recycled as needed.

coords

See Details below.

smooth

Whether to average normals at vertices for a smooth appearance.

normals

User-specified normals at each vertex. Requires smooth = FALSE.

texcoords

Texture coordinates at each vertex.

...

See Details below.

Details

These functions construct a mesh3d object corresponding to the triangulation in x. The plot3d and persp3d methods plot it.

The coords parameter allows surfaces to be plotted over any coordinate plane. It should be a permutation of the column names c("x", "y", "z"). The first will be used as the x coordinate, the second as the y coordinate, and the third as the z coordinate.

The ... parameters in plot3d.triSht and plot3d.tri are passed to persp3d; in persp3d.triSht and persp3d.tri they are passed to both as.mesh3d and persp3d.mesh3d; in as.mesh3d.triSht and as.mesh3d.tri they are used as material parameters in a tmesh3d call.

"tri" objects may contain constraints. These appear internally as extra nodes, representing either the inside or outside of boundaries on the region being triangulated. Each of these nodes should also have a z value, but triangles corresponding entirely to constraint nodes will not be drawn. In this way complex, non-convex regions can be triangulated. See the second example below.

Examples

x <- rnorm(200, sd = 5)
y <- rnorm(200, sd = 5)
r <- sqrt(x^2 + y^2)
z <- 10 * sin(r)/r
col <- cm.colors(20)[1 + round(19*(z - min(z))/diff(range(z)))]
save <- NULL
if ((haveinterp <- requireNamespace("interp", quietly = TRUE))) {
  save <- options(rgl.meshColorWarning = FALSE)
  dxy <- interp::tri.mesh(x, y)
  open3d()
  persp3d(dxy, z, col = col, meshColor = "vertices")
}
if (haveinterp) {
  open3d()
  # Do it without smoothing and with a different orientation.
  persp3d(dxy, z, col = col, coords = c("z", "x", "y"), smooth = FALSE)
}
if (requireNamespace("tripack", quietly = TRUE)) {
  if (is.null(save))
    save <- options(rgl.meshColorWarning = FALSE)

  # Leave a circular hole around (3, 0)
  theta <- seq(0, 2*pi, length.out = 30)[-1]
  cx <- 2*cos(theta) + 3
  cy <- 2*sin(theta)
  keep <- (x - 3)^2 + y^2 > 4
  dxy2 <- tripack::tri.mesh(x[keep], y[keep])
  dxy2 <- tripack::add.constraint(dxy2, cx, cy)
  z <- dxy2$x^2 - dxy2$y^2
  col <- terrain.colors(20)[1 + round(19*(z - min(z))/diff(range(z)))]
  open3d()
  persp3d(dxy2, z, col = col)
}
options(save)