R/polygon_grid.R

In daffp/shapegrid: Create grid of points

#' Polygon grid
#' 
#' Create a grid of points within a polygon (DON'T USE -- doesn't work correctly. See plot in examples.)
#'
#' @param N The number of subintervals each side should be divided into i.e. there are (N+1) points on a side.
#' @param NV The number of vertices in the polygon.
#' @param vertices A vector of length \code{2.NV} giving the (x,y) coordinates of each vertex of the polygon or a matrix with two rows and \code{2.NV} columns of vertex coordinates.
#' @return Returns a matrix with the x and y positions of each point in the grid.
#' @details Code taken from \url{https://people.sc.fsu.edu/~jburkardt/cpp_src/polygon_grid/polygon_grid.html}. 
#' @examples
#' v = cbind( c(0, 0.5), c(0.5,0), c(1,1), c(1.5,0),c(2,0.5))
#' par(mfrow=c(1,3))
#' for(i in 1:3){
#'   pts = polygon_grid(10, ncol(v)-i+1, c(v[, seq(ncol(v)-i+1)]))
#'   plot(pts, main=bquote(.(i)~ "vertices")) 
#' }
#' @export
polygon_grid = function(N, NV, vertices){
  
  v = c(vertices)
  mat = polygon_gridcpp(N, NV, v)
  return(mat)
}