takahashi-naminamikakukaku-movie.R

library(animation)
library(grid)
graphics.off()

N = 500
x = seq(0, 1, length.out = N)
xd = 30
NY = 36
ys = (0:NY/NY)[rep(c(F,T,T,F), length.out=NY)]
di = rep(c(1,1,-1,-1), length.out = NY)
f = function(xo) {
  grid.rect(gp = gpar(fill = "gray50"))
  for (i in 1:length(ys)) {
    y = (cos(xd*(x)*pi)+1)/100*0.25 + ys[i]
    id = (sin(xd/2*(x+di[i]*xo)*pi))>0
    id2 = cumsum(abs(c(0, diff(id))))
    id2[id<=0] = NA
    grid.lines(x, y, gp = gpar(col = "white", lwd = 3))
    grid.polyline(x, y, id = id2, gp = gpar(col = "black", lwd = 3))
  }
}
saveGIF({
  ani.options(nmax = 50)
  for (xo in seq(0, 1/xd*4, length.out = 50)) {
    grid.newpage()
    f(xo)
  }}, interval = 0.05, movie.name = "bm_demo.gif", ani.width = 600, ani.height = 600)