R/vcgIsolated.r

In Rvcg: Manipulations of Triangular Meshes Based on the 'VCGLIB' API

#' Remove isolated pieces from a surface mesh or split into connected components
#' 
#' Remove isolated pieces from a surface mesh, selected by a
#' minimum amount of faces or of a diameter below a given threshold.
#' Also the option only to keep the largest piece can be selected or to split a mesh into connected components.
#' 
#' 
#' @param mesh triangular mesh of class "mesh3d".
#' @param facenum integer: all connected pieces with less components are
#' removed. If not specified or 0 and diameter is NULL, then only the component
#' with the most faces is kept. 
#' @param diameter numeric: all connected pieces smaller diameter are removed
#' removed. \code{diameter = 0} removes all component but the largest ones. This option overrides the option \code{facenum}.
#' @param split logical: if TRUE, a list with all connected components (optionally matching requirements facenum/diameter) of the mesh will be returned.
#' @param keep integer: if split=T, \code{keep} specifies the number of largest chunks (number of faces) to keep. 
#' @param silent logical, if TRUE no console output is issued.
#' @return returns the reduced mesh.
#' @author Stefan Schlager
#' @seealso \code{\link{vcgPlyRead}}
#' @examples
#' \dontrun{
#' data(humface)
#' cleanface <- vcgIsolated(humface)
#' }
#' 
#' @export vcgIsolated
vcgIsolated <- function(mesh,facenum=NULL,diameter=NULL,split=FALSE,keep=0, silent=FALSE) {
    if (!inherits(mesh,"mesh3d"))
        stop("argument 'mesh' needs to be object of class 'mesh3d'")
    if (is.null(facenum))
        facenum <- 0
    if (!is.null(diameter))
        facenum <- -1

    if (is.null(diameter))
        diameter <- 0
    storage.mode(facenum) <- "integer"
    storage.mode(diameter) <- "double"

    mesh <- meshintegrity(mesh,facecheck=TRUE)
    vb <- mesh$vb[1:3,,drop=FALSE]
    it <- mesh$it-1
    dimit <- dim(it)[2]
    dimvb <- dim(vb)[2]
    tmp <- .Call("Risolated", vb, it, diameter, facenum,silent,split)
    if (!split) {
        ## handle vertex color
        if (!is.null(mesh$material$color)) {
            if (length(tmp$remvert)) {
                tmp$material$color <- mesh$material$color[-which(as.logical(tmp$remvert))]
            } else {
                tmp$material$color <- mesh$material$color
            }
        }
        
    }
    if (split) {
        if (length(tmp)) { 
            ll <- length(tmp)
            nverts <- sapply(tmp,function(x) x <- ncol(x$it))
            tmp <- tmp[order(nverts,decreasing = T)]
            if (keep > 0) 
                ll <- min(ll,keep)
            tmp <- tmp[1:ll]
            if (!silent)
                cat(paste0("mesh is split into ",ll," pieces\n"))
        } else {
            stop("no parts match your requirements")
        }
    }
    invisible(tmp)
}