Pyramid Pie Chart Animation in ggplot2

pyramid.ani.R

library("ggplot2")
library("animation")


saveGIF({
  for(shadyside in 1:39)
  {
    sides <- c("Sky", "Sunny side of pyramid", "Shady side of pyramid")
    amounts <- c(150, 40 - shadyside, shadyside)
    
    mydf <- data.frame(values=ordered(rep(sides, amounts), levels = sides))
    
    p <- ggplot(mydf, aes(x = factor(1), fill=factor(values))) + 
      geom_bar(width = 1) + 
      coord_polar(theta = "y", start = 3.8, direction = -1) + 
      scale_fill_manual(values = c("#0095d9", "#f5e837", "#c4b633")) + 
      theme(axis.line = element_blank(),
            axis.title = element_blank(),
            axis.text = element_blank(),
            axis.ticks = element_blank(),
            legend.position = c(1, .9),
            legend.title = element_blank(),
            panel.background = element_blank())
    
    print(p)
  }
}, interval = 1/30, ani.width = 550, ani.height=450)