117 lines
2.8 KiB
Julia
117 lines
2.8 KiB
Julia
module SimpleRayTracer
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using LinearAlgebra
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using StaticArrays
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using Images
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using GeometryBasics
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using Rotations
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export OrthogonalCamera
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export World, Ray
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export Sphere
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abstract type AbstractCamera end
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abstract type AbstractObject end
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struct OrthogonalCamera{T<:AbstractFloat} <: AbstractCamera
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origin::Vec3{T}
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size::Tuple{T, T}
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rotation::RotXYZ{T}
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end
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function get_rays(camera::OrthogonalCamera, resolution::Tuple{I, I}) where {I<:Integer}
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R = camera.rotation
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X, Y = camera.size
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Nx, Ny = resolution
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screen_pixel_position = [R*Vec3(x, y, 0.0) + camera.origin for y = LinRange(Y/2, -Y/2, Ny), x = LinRange(-X/2, X/2, Nx)]
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[Ray(p, R*Vec3(0.0, 0.0, 1.0)) for p in screen_pixel_position]
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end
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struct PinHoleCamera{T<:AbstractFloat} <: AbstractCamera
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origin::Vec3{T}
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distance::T
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base::SMatrix{3, 3, T}
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size::Tuple{T, T}
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end
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function PinHoleCamera(origin, lookAt, up, distance, size)
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w = origin - lookAt |> normalize
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u = up × w |> normalize
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v = w × u
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B = [u v w]
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PinHoleCamera(origin, distance, B, size)
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end
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function get_rays(camera::PinHoleCamera, resolution::Tuple{I, I}) where {I<:Integer}
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origin = camera.origin
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d = camera.distance
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X, Y = camera.size
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B = camera.base
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Nx, Ny = resolution
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[Ray(origin, B*Vec3(x, y, -d)) for y = LinRange(Y/2, -Y/2, Ny), x = LinRange(-X/2, X/2, Nx)]
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end
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struct Ray{T<:AbstractFloat}
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origin::Vec3{T}
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direction::Vec3{T}
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function Ray(o::Vec3{T}, d::Vec3{T}) where {T<:AbstractFloat}
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new{T}(o, d |> normalize)
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end
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end
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struct HitInfo
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hit::Bool
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color::RGB{N0f8}
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end
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struct World
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objects::Vector
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background::RGB{N0f8}
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function World(color)
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new([], color)
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end
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end
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Base.push!(w::World, x::AbstractObject) = push!(w.objects, x)
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struct Sphere{T<:AbstractFloat} <: AbstractObject
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origin::Vec3{T}
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radius::T
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color::RGB{N0f8}
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end
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function check_hit(ray::Ray{T}, sphere::Sphere{T})::Tuple{Bool, T} where {T <: AbstractFloat}
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p = ray.origin - sphere.origin
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a = ray.direction ⋅ ray.direction
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b = 2 * (p ⋅ ray.direction)
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c = p ⋅ p - sphere.radius^2
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Δ = b^2 - 4a*c
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Δ < 0.0 && return false, -1.0
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x, z = -b/(2a), √Δ/(2a)
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t = x - z
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t = t < eps() ? x + z : t
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return t < eps() ? (false, -1.0) : (true, t)
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end
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function trace_ray(world::World, ray::Ray)::HitInfo
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mindist = Float64 |> typemax |> prevfloat
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hit = false
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color = world.background
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for obj in world.objects
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hit, dist = check_hit(ray, obj)
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if hit && dist < mindist
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mindist = dist
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hit = true
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color = obj.color
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end
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end
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return HitInfo(hit, color)
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end
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function render(world, camera, resolution)
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rays = get_rays(camera, resolution)
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[trace_ray(world, ray).color for ray in rays];
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end
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end
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