Module 13: Animating in R

 Using Yihui Xie's animation package, I opted to try to make a simple animation of a bouncing ball. While I'm more than pleased with the results, I'm still at a loss as to why the ball isn't bouncing as it should (it's meant to flatten somewhat at the bottom). Regardless, it's still fascinating to see an actual animation having been created with only R code.

Code:

library(animation)

# Function to create the animation frames

bounce_animation <- function(height = 10, gravity = 0.1, nframes = 25, x = 0.5, filename = "bounce_animation.gif") {

  # Initialize variables

  y <- height

  velocity <- 0

  squished <- FALSE

  

  # Create and save the animation

  saveGIF({

    for (i in 1:nframes) {

      # Update position and velocity

      y <- y + velocity

      velocity <- velocity - gravity

      

      # Squish effect when ball hits the ground

      if (y < 0) {

        y <- 0

        velocity <- -velocity * 0.9  # Loss of energy upon bouncing

        squished <- TRUE

      } else {

        squished <- FALSE

      }

      

      # Plot the ball with squish effect

      plot(0, 0, type = "n", xlim = c(-1, 1), ylim = c(-1, height), xlab = "", ylab = "")

      if (squished) {

        symbols(0, y, circles = 1, inches = c((0.5 * x), 0.5), aspect = 1, add = TRUE)  # Oval shape when squished?

      } else {

        symbols(0, y, circles = 1, inches = c(0.5, 0.5), add = TRUE)  # Original ball shape

      }

      

      # Pause between frames

      Sys.sleep(0.02)  # Adjusted delay between frames for smoother animation

    }

  }, movie.name = filename)

}

# Create and save the animation

bounce_animation(x = 0.8)