Evaluate intersections with objects

In a sense, this is a vectorized alternative to seesGoal, but is applied more broadly to evaluate whether there are intersections between the edges that were created and the objects in the environment.

Usage

prune_edges(objects, segments, cpp = TRUE)

Arguments

objects

List of objects that extend the object-class.

segments

Numerical matrix of size N x 4 containing the coordinates of the line segments in order x_1, y_1, x_2, y_2.

cpp

Logical denoting whether to use the Rcpp alternative (TRUE) or the R alternative of this function (FALSE). Defaults to TRUE.

Value

Logical vector denoting whether a given edge can be retained (TRUE) or should be discarded (FALSE)

Details

In this function, a lot of the heavy lifting is done by the line_intersection method.

Note that this function is kept separate from evaluate_edges so that it can still be used for the same purposes as seesGoal was originally used for.

See also

adjust_edges, create_edges, evaluate_edges, line_intersection

Examples

# Let's create a list of objects
objects <- list(rectangle(center = c(0, 0), size = c(1, 1)))

# Create some segments that do and do not go though the objects in the 
# background
segments <- cbind(c(-0.75, -0.75, -0.75), 
                  c(0, 0, 0),
                  c(-0.75, 0.75, 0.95), 
                  c(0.75, 0, 0.95))
segments
#>       [,1] [,2]  [,3] [,4]
#> [1,] -0.75    0 -0.75 0.75
#> [2,] -0.75    0  0.75 0.00
#> [3,] -0.75    0  0.95 0.95

# Do the test
prune_edges(objects, segments)
#> [1]  TRUE FALSE FALSE