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#!/usr/bin/env -S nim r -d:release --verbosity:0 --hints:off
import std/options
type
Point = tuple[x, y: float]
Line = (Point, Point)
func getIntersection(l1, l2: Line): Option[Point] =
## can't handle co-linear lines
let
ix: Line =
((l1[1].x - l1[0].x, l1[1].y - l1[0].y), (l2[1].x - l2[0].x, l2[1].y - l2[0].y))
s: float =
(-ix[0].y * (l1[0].x - l2[0].x) + ix[0].x * (l1[0].y - l2[0].y)) /
(-ix[1].x * ix[0].y + ix[0].x * ix[1].y)
t: float =
(ix[1].x * (l1[0].y - l2[0].y) - ix[1].y * (l1[0].x - l2[0].x)) /
(-ix[1].x * ix[0].y + ix[0].x * ix[1].y)
if s >= 0 and s <= 1 and t >= 0 and t <= 1:
# Collision detected
return some((l1[0].x + (t * ix[0].x), l1[0].y + (t * ix[0].y)))
none(Point)
when isMainModule:
import std/unittest
const
TestLines = [
((0.0, 0.0), (10.0, 10.0)), ((10.0, 0.0), (0.0, 10.0)),
((0.0, 0.0), (10.0, 10.0)), ((10.0, 0.0), (6.0, 4.0)),
]
Expected = [some(Point (5.0, 5.0)), none(Point)]
suite "Intersection of two lines":
test "intersection detected":
check getIntersection(TestLines[0], TestLines[1]) == Expected[0]
test "no intersection":
check getIntersection(TestLines[2], TestLines[3]) == Expected[1]
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