Unique edges of a triangulation

The index pairs of every triangle edge once, for plotting with graphics::segments() or for building an edge table.

Usage

cdt_edges(x)

Arguments

x

result of cdt_triangulate()

Value

integer matrix (2 columns) of 1-based vertex indices

Examples

r <- cdt_triangulate(c(0, 1, 1, 0, 0.5), c(0, 0, 1, 1, 0.5))
e <- cdt_edges(r)
plot(r$P, asp = 1)
segments(r$P[e[, 1], 1], r$P[e[, 1], 2], r$P[e[, 2], 1], r$P[e[, 2], 2])