hist3D 2D plot in background in R - r

Question

Is it possible to add a 2d plot to a 3D plot in R?
I have the following R code that generates a 3d bar plot.
dt = structure(c(1, 1, 1, 3,
0, 2, 2, 1,
1, 2, 1, 3,
2, 6, 3, 1,
1, 2, 3, 0,
1, 0, 2, 1,
1,2,2,2), .Dim = c(4L, 7L), .Dimnames = list(c("0-50",
"51-60", "61-70", "71-80"
), c("0-50", "51-60", "61-70", "71-80", "81-90", "91-100", "101-Inf")))
m <- matrix(rep(seq(4),each=7), ncol=7, nrow=4, byrow = TRUE)
hist3D(x = 1:4, z = dt, scale = T,bty="g", phi=35,theta=30,border="black",space=0.15,col = jet.col(5, alpha = 0.8), add = F, colvar = m, colkey = F, ticktype = "detailed")
The hist3d call only:
hist3D(x = 1:4, z = dt, scale = T,bty="g", phi=35,theta=30, border="black", space=0.15,col = jet.col(5, alpha = 0.8), add = F, colvar = m, colkey = F, ticktype = "detailed")
This generates the following 3d plot:
What I'm looking for is being able to add a plot in the position where the grey grid is. Is it possible?
Thanks!

Answer 1

As far as I know, there isn't a good function to make a barplot in RGL. I suggest a manual method.
dt = structure(c(1, 1, 1, 3,
0, 2, 2, 1,
1, 2, 1, 3,
2, 6, 3, 1,
1, 2, 3, 0,
1, 0, 2, 1,
1,2,2,2), .Dim = c(4L, 7L), .Dimnames = list(c("0-50",
"51-60", "61-70", "71-80"
), c("0-50", "51-60", "61-70", "71-80", "81-90", "91-100", "101-Inf")))
Making 3D barplot in RGL
library(rgl)
# make dt xyz coordinates data
dt2 <- cbind( expand.grid(x = 1:4, y = 1:7), z = c(dt) )
# define each bar's width and depth
bar_w <- 1 * 0.85
bar_d <- 1 * 0.85
# make a base bar (center of undersurface is c(0,0,0), width = bar_w, depth = bar_d, height = 1)
base <- translate3d( scale3d( cube3d(), bar_w/2, bar_d/2, 1/2 ), 0, 0, 1/2 )
# make each bar data and integrate them
bar.list <- shapelist3d(
apply(dt2, 1, function(a) translate3d(scale3d(base, 1, 1, a[3]), a[1], a[2], 0)),
plot=F)
# set colors
for(i in seq_len(nrow(dt2))) bar.list[[i]]$material$col <- rep(jet.col(5)[c(1:3,5)], 7)[i]
open3d()
plot3d(0,0,0, type="n", xlab="x", ylab="y", zlab="z", box=F,
xlim=c(0.5, 4.5), ylim=c(0.5, 7.5), zlim=c(0, 6.2), aspect=T, expand=1)
shade3d(bar.list, alpha=0.8)
wire3d(bar.list, col="black")
light3d(ambient="black", diffuse="gray30", specular="black") # light up a little
Add a 2d plot
# show2d() uses 2d plot function's output as a texture
# If you need the same coordinates of 2d and 3d, plot3d(expand=1) and show2d(expand=1),
# the same xlims, equivalent plot3d(zlim) to 2d plot's ylim, 2d plot(xaxs="i", yaxs="i") are needed.
show2d({
par(mar = c(0,0,0,0))
barplot(c(3,4,5,6), yaxs="i", ylim=c(0, 6.2))
},
expand = 1 , face = "y+", texmipmap = F) # texmipmap=F makes tone clear