R/compute_ghost_coord.R

In mcanouil/ggpacman: A 'ggplot2' and 'gganimate' Version of Pac-Man

#' Compute Ghost Coordinates
#'
#' @param data A `data.frame` with the coordinates of Ghost moves.
#'
#' @return Returns a `tibble` of cartesian coordinates.
#'
#' @export
compute_ghost_coord <- function(data) {
  data %>%
    tidyr::unnest(c("x", "y")) %>%
    dplyr::mutate(
      X0 = .data[["x"]],
      Y0 = .data[["y"]],
      state_x = sign(round(.data[["x"]]) - dplyr::lag(round(.data[["x"]]))),
      state_y = sign(round(.data[["y"]]) - dplyr::lag(round(.data[["y"]]))),
      direction = dplyr::case_when(
        (is.na(.data[["state_x"]]) | .data[["state_x"]] %in% 0) &
          (is.na(.data[["state_y"]]) | .data[["state_y"]] %in% 0) ~ "middle",
        .data[["state_x"]] == 1 & .data[["state_y"]] == 0 ~ "right",
        .data[["state_x"]] == -1 & .data[["state_y"]] == 0 ~ "left",
        .data[["state_x"]] == 0 & .data[["state_y"]] == -1 ~ "down",
        .data[["state_x"]] == 0 & .data[["state_y"]] == 1 ~ "up"
      )
    ) %>%
    tidyr::unnest("direction") %>%
    dplyr::mutate(state = list(1:4)) %>%
    tidyr::unnest("state") %>%
    dplyr::mutate(
      step = 1:dplyr::n(),
      noise_x = stats::rnorm(dplyr::n(), mean = 0, sd = 0.05),
      noise_y = stats::rnorm(dplyr::n(), mean = 0, sd = 0.05),
      body = purrr::pmap(
        .l = list(.data[["x"]], .data[["y"]], .data[["noise_x"]], .data[["noise_y"]]),
        .f = function(.x, .y, .noise_x, .noise_y) {
          dplyr::mutate(
            .data = get(utils::data("ghost_body")),
            x = .data[["x"]] + .x + .noise_x,
            y = .data[["y"]] + .y + .noise_y
          )
        }
      ),
      eyes = purrr::pmap(
        .l = list(.data[["x"]], .data[["y"]], .data[["noise_x"]], .data[["noise_y"]], .data[["direction"]]),
        .f = function(.x, .y, .noise_x, .noise_y, .direction) {
          dplyr::mutate(
            .data = dplyr::filter(get(utils::data("ghost_eyes")), .data[["direction"]] == .direction),
            x0 = .data[["x0"]] + .x + .noise_x,
            y0 = .data[["y0"]] + .y + .noise_y,
            direction = NULL
          )
        }
      ),
      x = NULL,
      y = NULL
    )
}