Creating the River Derwent, jumping out of the map

jumping_water.R

library(dplyr)
library(rayshader)
loadzip = tempfile() 
download.file("https://www.tylermw.com/data/dem_01.tif.zip", loadzip)
localtif = raster::raster(unzip(loadzip, "dem_01.tif"))
unlink(loadzip)

xposfunction = function(x0,v0,a0, loss=1/4, low,starttime,cutoff) {
  xpos = rep(x0,360)
  for(i in starttime:360) {
    x0 = x0 + v0
    if(x0 > low) {
      v0 = v0 - a0
    } else {
      x0 = -x0
      v0 = -v0*loss
    }
    xpos[i] = x0
  }
  xpos[(cutoff+starttime):360] = low
  xpos
}

heightvals = c(xposfunction(0,5.5,0.08,1/2,0,1,330)[66:360],
               xposfunction(0,5.5,0.08,1/2,0,1,330)[1:65])

elmat_all_na = matrix(NA,nrow(elmat), ncol(elmat))
elmat_all_na[1,1] = 400
elmat_no_water = elmat
elmat_no_water[rayshader:::fliplr(detect_water(elmat)) == 1] = NA
elmat_no_water %>%
  sphere_shade() %>%
  plot_3d(elmat_no_water, zscale=10,windowsize = c(1000,1000),soliddepth=-40,shadowdepth = -300,
          background = "#ffd9e0", shadowcolor = "#8a4854", solidcolor = "#241605", solidlinecolor = NULL)
 
keepids = rgl::rgl.ids()

elmat_water = elmat
elmat_water[rayshader:::fliplr(detect_water(elmat)) == 0] = NA

thetaval = 45 + 30 * sinpi(1:360/180)

for(i in 1:360) {
  elmat_water %>%
    sphere_shade() %>%
    add_water(detect_water(elmat), color = "#6fbdf2") %>%
    plot_3d(elmat_water+heightvals[i]*10, zscale=10,windowsize = c(1000,1000),soliddepth=heightvals[i]-40,
            shadow=FALSE,
            background = "#ffd9e0", solidcolor = "#4b86ad", solidlinecolor = NULL) 
  elmat_all_na %>%
    sphere_shade() %>%
    plot_3d(elmat_all_na, zscale=10,windowsize = c(1000,1000),solid=TRUE, soliddepth = 399,
            shadow=FALSE,background = "#ffd9e0",) 

  removeids = rgl::rgl.ids() %>%
    filter(!(id %in% keepids$id))
  
  render_camera(theta=thetaval[i],zoom=0.8,fov=0)
  rgl::par3d(userMatrix = rgl::par3d()$userMatrix %*% t(rgl::translationMatrix(0,100,0)))
  
  render_snapshot(title_text = "River Derwent, Tasmania", title_size = 40, 
                  filename=glue::glue("waterslicename{i}"))
  rgl::rgl.pop(id = removeids$id)
}

system("ffmpeg -framerate 60 -i waterslicename%d.png -pix_fmt yuv420p waterslicenameweb.mp4")

Hi Tyler, thanks for sharing the gist (I came across it on twitter). I'm having trouble running it, the object elmat seems to be used before it is defined, so I set elmat to be localtif and that worked to a point, but there might be another issue. Regards, Martin