46 lines
1006 B
Plaintext
46 lines
1006 B
Plaintext
module RayCastings
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export Point
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struct Point{T}
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x::T
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y::T
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end
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Base.show(io::IO, p::Point) = print(io, "($(p.x), $(p.y))")
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const Edge = Tuple{Point{T}, Point{T}} where T
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Base.show(io::IO, e::Edge) = print(io, "$(e[1]) ∘-∘ $(e[2])")
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function rayintersectseg(p::Point{T}, edge::Edge{T}) where T
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a, b = edge
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if a.y > b.y
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a, b = b, a
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end
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if p.y ∈ (a.y, b.y)
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p = Point(p.x, p.y + eps(p.y))
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end
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rst = false
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if (p.y > b.y || p.y < a.y) || (p.x > max(a.x, b.x))
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return false
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end
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if p.x < min(a.x, b.x)
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rst = true
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else
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mred = (b.y - a.y) / (b.x - a.x)
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mblu = (p.y - a.y) / (p.x - a.x)
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rst = mblu ≥ mred
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end
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return rst
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end
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isinside(poly::Vector{Tuple{Point{T}, Point{T}}}, p::Point{T}) where T =
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isodd(count(edge -> rayintersectseg(p, edge), poly))
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connect(a::Point{T}, b::Point{T}...) where T =
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[(a, b) for (a, b) in zip(vcat(a, b...), vcat(b..., a))]
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end # module RayCastings
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