selectpoints3d: Select points from a scene
In trestletech/rgl: 3D visualization device system (OpenGL)

Description Usage Arguments Details Value Author(s) See Also Examples

This function uses the select3d function to allow the user to choose a point or region in the scene, then reports on all the vertices in or near that selection.

1 2	selectpoints3d(objects = rgl.ids()$id, value = TRUE, closest = TRUE, multiple = FALSE, ...)

`objects`	A vector of object id values to use for the search.
`value`	If `TRUE`, return the coordinates of the points; otherwise, return their indices.
`closest`	If `TRUE`, return the points closest to the selection of no points are exactly within it.
`multiple`	If `TRUE` or a function, do multiple selections. See the Details below.
`...`	Other parameters to pass to `select3d`.

The multiple argument may be a logical value or a function. If logical, it controls whether multiple selections will be performed. If multiple is FALSE, a single selection will be performed; it might contain multiple points. If TRUE, multiple selections will occur and the results will be combined into a single matrix.

If multiple is a function, it should take a single argument. This function will be called with the argument set to a matrix containing newly added rows to the value, i.e. it will contain coordinates of the newly selected points (if value = TRUE), or the indices of the points (if value = FALSE). It should return a logical value, TRUE to indicate that selection should continue, FALSE to indicate that it should stop.

In either case, if multiple selections are being performed, the ESC key will stop the process.

If value is TRUE, a 3-column matrix giving the coordinates of the selected points. All rows in the matrix will be unique even if multiple vertices have the same coordinates.

If value is FALSE, a 2-column matrix containing columns:

`id`	The object id containing the point.
`index`	The index of the point within `rgl.attrib(id, "vertices")`. If multiple points have the same coordinates, all indices will be returned.

Duncan Murdoch

select3d to return a selection function.

xyz <- cbind(rnorm(20), rnorm(20), rnorm(20))
ids <- plot3d( xyz )

if (interactive()) {
  # Click near a point to select it and put a sphere there.
  # Press ESC to quit...

  # This version returns coordinates
  selectpoints3d(ids["data"], 
     multiple = function(x) {
        spheres3d(x, color = "red", alpha = 0.3, radius = 0.2)
        TRUE
     })

  # This one returns indices
  selectpoints3d(ids["data"], value = FALSE,
     multiple = function(ids) {
        spheres3d(xyz[ids[, "index"], , drop = FALSE], color = "blue", 
                  alpha = 0.3, radius = 0.2)
        TRUE
     })
}