Ray-casting algorithm: Difference between revisions
Added Wren
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True False False False False True False
True True False False False True False
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=={{header|Wren}}==
{{trans|Java}}
{{libheader|Wren-math}}
{{libheader|Wren-fmt}}
<lang ecmascript>import "/math" for Math
import "/fmt" for Fmt
class RayCasting {
static intersects(a, b, p) {
if (a[1] > b[1]) return intersects(b, a, p)
if (p[1] == a[1] || p[1] == b[1]) p[1] = p[1] + 0.0001
if (p[1] > b[1] || p[1] < a[1] || p[0] >= Math.max(a[0], b[0])) return false
if (p[0] < Math.min(a[0], b[0])) return true
var red = (p[1] - a[1]) / (p[0] - a[0])
var blue = (b[1] - a[1]) / (b[0] - a[0])
return red >= blue
}
static contains(shape, pnt) {
var inside = false
var len = shape.count
for (i in 0...len) {
if (intersects(shape[i], shape[(i + 1) % len], pnt)) inside = !inside
}
return inside
}
static square { [[0, 0], [20, 0], [20, 20], [0, 20]] }
static squareHole { [[0, 0], [20, 0], [20, 20], [0, 20], [5, 5], [15, 5], [15, 15], [5, 15]] }
static strange { [[0, 0], [5, 5], [0, 20], [5, 15], [15, 15], [20, 20], [20, 0]] }
static hexagon { [[6, 0], [14, 0], [20, 10], [14, 20], [6, 20], [0, 10]] }
static shapes { [square, squareHole, strange, hexagon] }
}
var testPoints = [[10, 10], [10, 16], [-20, 10], [0, 10], [20, 10], [16, 10], [20, 20]]
for (shape in RayCasting.shapes) {
for (pnt in testPoints) Fmt.write("$7s ", RayCasting.contains(shape, pnt))
System.print()
}</lang>
{{out}}
<pre>
true true false true false true false
false true false false false true false
true false false false false true false
true true false false false true false
</pre>
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