support silicate BGM

[mdsumner]

From @mdsumner on February 28, 2018 1:53

From @mdsumner on September 14, 2016 6:2

BGM needs

• mixed quads and triangles (use extrude3d though later use RTriangle)
• bgm data structure probably should be rangl from the start

Copied from original issue: hypertidy/anglr#33

Copied from original issue: hypertidy/silicate#54

[mdsumner]

A start

## Spatially explicit ecosystem model (Atlantis)


library(rbgm)
bgm <- bgmfile(bgmfiles::bgmfiles("antarctica_99"))

bgm$boxes$botz
cols <- viridis::viridis(nrow(bgm$boxes))
for (i in seq(nrow(bgm$boxes))) {
#x <- sp::spTransform(boxSpatial(bgm)[i, ], "+proj=laea +lat_0=-65 +lon_0=100")
x <- boxSpatial(bgm)[i, ]
dz <- rbgm:::build_dz(x$botz)
#z0 <- 0
alp <- seq(0.05, 0.9, length = length(dz))
for (zi in seq_along(dz)) {
  if (dz[zi] > 0) {
    p <- spbabel::sptable(x)[, c("x_", "y_")]
    rglobj <- rgl::extrude3d(p, thickness = dz[zi])
    rglobj$vb[3,] <- rglobj$vb[3,] - sum(dz[seq(zi)])
   # print(sum(dz[seq(zi)]))
    rgl::shade3d(rglobj, col = cols[i], alpha = alp[zi], 
                 specular = "black")
  }
}
}
rgl::aspect3d(1, 1, 1e-3)