Add primitive shape
Adds a shape node to the current scene.
points3d(x, y = NULL, z = NULL, ...) lines3d(x, y = NULL, z = NULL, ...) segments3d(x, y = NULL, z = NULL, ...) triangles3d(x, y = NULL, z = NULL, ...) quads3d(x, y = NULL, z = NULL, ...)
x, y, z |
coordinates. Any reasonable way of defining the
coordinates is acceptable. See the function |
... |
Material properties (see |
The functions points3d, lines3d, segments3d,
triangles3d and quads3d add points, joined lines, line segments,
filled triangles or quadrilaterals to the plots. They correspond to the OpenGL types
GL_POINTS, GL_LINE_STRIP, GL_LINES, GL_TRIANGLES and GL_QUADS respectively.
Points are taken in pairs by segments3d, triplets as the vertices
of the triangles, and quadruplets for the quadrilaterals. Colors are applied vertex by vertex;
if different at each end of a line segment, or each vertex of a polygon, the colors
are blended over the extent of the object. Polygons
must be non-degenerate and quadrilaterals must be entirely
in one plane and convex, or the results are undefined.
These functions call the lower level functions rgl.points, rgl.linestrips.
The appearance of the new objects are defined by the material properties.
See rgl.material for details.
The two principal differences between the rgl.* functions and
the *3d functions are that the former set all unspecified
material properties to defaults, whereas the latter use current values
as defaults; the former make persistent changes to material properties
with each call, whereas the latter make temporary changes only for the
duration of the call.
Each function returns the integer object ID of the shape that
was added to the scene. These can be passed to pop3d
to remove the object from the scene.
Ming Chen and Duncan Murdoch
# Show 12 random vertices in various ways.
M <- matrix(rnorm(36), 3, 12, dimnames = list(c('x', 'y', 'z'),
rep(LETTERS[1:4], 3)))
# Force 4-tuples to be convex in planes so that quads3d works.
for (i in c(1, 5, 9)) {
quad <- as.data.frame(M[, i + 0:3])
coeffs <- runif(2, 0, 3)
if (mean(coeffs) < 1) coeffs <- coeffs + 1 - mean(coeffs)
quad$C <- with(quad, coeffs[1]*(B - A) + coeffs[2]*(D - A) + A)
M[, i + 0:3] <- as.matrix(quad)
}
open3d()
# Rows of M are x, y, z coords; transpose to plot
M <- t(M)
shift <- matrix(c(-3, 3, 0), 12, 3, byrow = TRUE)
points3d(M)
lines3d(M + shift)
segments3d(M + 2*shift)
triangles3d(M + 3*shift, col = 'red')
quads3d(M + 4*shift, col = 'green')
text3d(M + 5*shift, texts = 1:12)
# Add labels
shift <- outer(0:5, shift[1, ])
shift[, 1] <- shift[, 1] + 3
text3d(shift,
texts = c('points3d', 'lines3d', 'segments3d',
'triangles3d', 'quads3d', 'text3d'),
adj = 0)
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