Faces from a mesh: Difference between revisions

=={{header|Wren}}==

{{trans|Go}}

{{libheader|Wren-sort}}

{{libheader|Wren-fmt}}

<lang ecmascript>import "/sort" for Sort

import "/fmt" for Fmt

// Assumes s1, s2 are of same length.

var sliceEqual = Fn.new { |s1, s2|

for (i in 0...s1.count) {

if (s1[i] != s2[i]) return false

}

return true

}

// Check two perimeters are equal.

var perimEqual = Fn.new { |p1, p2|

var le = p1.count

if (le != p2.count) return false

for (p in p1) {

if (!p2.contains(p)) return false

}

// use copy to avoid mutating 'p1'

var c = p1.toList

for (r in 0..1) {

for (i in 0...le) {

if (sliceEqual.call(c, p2)) return true

// do circular shift to right

var t = c[-1]

for (i in le-2..0) c[i+1] = c[i]

c[0] = t

}

// now process in opposite direction

Sort.reverse(c) // reverses 'c' in place

}

return false

}

var faceToPerim = Fn.new { |face|

// use copy to avoid mutating 'face'

var le = face.count

if (le == 0) return []

var edges = List.filled(le, null)

for (i in 0...le) {

// check edge pairs are in correct order

if (face[i][1] <= face[i][0]) return []

edges[i] = [face[i][0], face[i][1]]

}

// sort edges in ascending order

var cmp = Fn.new { |e1, e2|

if (e1[0] != e2[0]) {

return (e1[0] - e2[0]).sign

}

return (e1[1] - e2[1]).sign

}

Sort.insertion(edges, cmp)

var first = edges[0][0]

var last = edges[0][1]

var perim = [first, last]

// remove first edge

edges.removeAt(0)

le = le - 1

while (le > 0) {

var i = 0

var outer = false

var cont = false

for (e in edges) {

var found = false

if (e[0] == last) {

perim.add(e[1])

last = e[1]

found = true

} else if (e[1] == last) {

perim.add(e[0])

last = e[0]

found = true

}

if (found) {

// remove i'th edge

edges.removeAt(i)

le = le - 1

if (last == first) {

if (le == 0) {

outer = true

break

} else {

return []

}

}

cont = true

break

}

i = i + 1

}

if (outer && !cont) break

}

return perim[0..-2]

}

System.print("Perimeter format equality checks:")

var areEqual = perimEqual.call([8, 1, 3], [1, 3, 8])

System.print(" Q == R is %(areEqual)")

areEqual = perimEqual.call([18, 8, 14, 10, 12, 17, 19], [8, 14, 10, 12, 17, 19, 18])

System.print(" U == V is %(areEqual)")

var e = [[7, 11], [1, 11], [1, 7]]

var f = [[11, 23], [1, 17], [17, 23], [1, 11]]

var g = [[8, 14], [17, 19], [10, 12], [10, 14], [12, 17], [8, 18], [18, 19]]

var h = [[1, 3], [9, 11], [3, 11], [1, 11]]

System.print("\nEdge to perimeter format translations:")

var i = 0

for (face in [e, f, g, h]) {

var perim = faceToPerim.call(face)

if (perim.isEmpty) {

Fmt.print(" $c => Invalid edge format", i + 69) // 'E' is ASCII 69

} else {

Fmt.print(" $c => $n", i + 69, perim)

}

}</lang>

{{out}}

<pre>

Perimeter format equality checks:

Q == R is true

U == V is true

Edge to perimeter format translations:

E => [1, 7, 11]

E => [1, 11, 23, 17]

E => [8, 14, 10, 12, 17, 19, 18]

E => Invalid edge format

</pre>