# NOT RUN {
#Example 1: Draw a ball
f <- function(x, y, z)x^2+y^2+z^2
x <- seq(-2,2,len=20)
contour3d(f,4,x,x,x)
contour3d(f,4,x,x,x, engine = "standard")
# ball with one corner removed.
contour3d(f,4,x,x,x, mask = function(x,y,z) x > 0 | y > 0 | z > 0)
contour3d(f,4,x,x,x, mask = function(x,y,z) x > 0 | y > 0 | z > 0,
engine="standard", screen = list(x = 290, y = -20),
color = "red", color2 = "white")
# ball with computed colors
w <- function(x,y,z) {
v <- sin(x) + cos(2 * y) * sin(5 * z)
r <- range(v)
n <- 100
i <- pmax(pmin(ceiling(n * (v - r[1]) / (r[2] - r[1])), n), 1)
terrain.colors(n)[i]
}
contour3d(f,4,x,x,x, color = w)
#Example 2: Nested contours of mixture of three tri-variate normal densities
nmix3 <- function(x, y, z, m, s) {
0.4 * dnorm(x, m, s) * dnorm(y, m, s) * dnorm(z, m, s) +
0.3 * dnorm(x, -m, s) * dnorm(y, -m, s) * dnorm(z, -m, s) +
0.3 * dnorm(x, m, s) * dnorm(y, -1.5 * m, s) * dnorm(z, m, s)
}
f <- function(x,y,z) nmix3(x,y,z,.5,.5)
g <- function(n = 40, k = 5, alo = 0.1, ahi = 0.5, cmap = heat.colors) {
th <- seq(0.05, 0.2, len = k)
col <- rev(cmap(length(th)))
al <- seq(alo, ahi, len = length(th))
x <- seq(-2, 2, len=n)
contour3d(f,th,x,x,x,color=col,alpha=al)
bg3d(col="white")
}
g(40,5)
gs <- function(n = 40, k = 5, cmap = heat.colors, ...) {
th <- seq(0.05, 0.2, len = k)
col <- rev(cmap(length(th)))
x <- seq(-2, 2, len=n)
m <- function(x,y,z) x > .25 | y < -.3
contour3d(f,th,x,x,x,color=col, mask = m, engine = "standard",
scale = FALSE, ...)
bg3d(col="white")
}
gs(40, 5, screen=list(z = 130, x = -80), color2 = "lightgray", cmap=rainbow)
# }
# NOT RUN {
#Example 3: Nested contours for FMRI data.
library(AnalyzeFMRI)
a <- f.read.analyze.volume(system.file("example.img", package="AnalyzeFMRI"))
a <- a[,,,1]
contour3d(a, 1:64, 1:64, 1.5*(1:21), lev=c(3000, 8000, 10000),
alpha = c(0.2, 0.5, 1), color = c("white", "red", "green"))
# alternative masking out a corner
m <- array(TRUE, dim(a))
m[1:30,1:30,1:10] <- FALSE
contour3d(a, 1:64, 1:64, 1.5*(1:21), lev=c(3000, 8000, 10000),
mask = m, color = c("white", "red", "green"))
contour3d(a, 1:64, 1:64, 1.5*(1:21), lev=c(3000, 8000, 10000),
color = c("white", "red", "green"),
color2 = c("gray", "red", "green"),
mask = m, engine="standard",
scale = FALSE, screen=list(z = 60, x = -120))
# }
# NOT RUN {
#Example 4: Separate the triangles from the contours of
# mixture of three tri-variate normal densities
nmix3 <- function(x, y, z, m, s) {
0.3*dnorm(x, -m, s) * dnorm(y, -m, s) * dnorm(z, -m, s) +
0.3*dnorm(x, -2*m, s) * dnorm(y, -2*m, s) * dnorm(z, -2*m, s) +
0.4*dnorm(x, -3*m, s) * dnorm(y, -3 * m, s) * dnorm(z, -3*m, s) }
f <- function(x,y,z) nmix3(x,y,z,0.5,.1)
n <- 20
x <- y <- z <- seq(-2, 2, len=n)
contour3dObj <- contour3d(f, 0.35, x, y, z, draw=FALSE, separate=TRUE)
for(i in 1:length(contour3dObj))
contour3dObj[[i]]$color <- rainbow(length(contour3dObj))[i]
drawScene.rgl(contour3dObj)
# }
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