From dc450860f356d002448131b7e3a919bce14b4993 Mon Sep 17 00:00:00 2001
From: zymon <s@zymon.org>
Date: Sat, 20 Jan 2024 14:56:37 +0100
Subject: [PATCH] Proste generowanie sceny z wykorzystaniem sledzenia promieni

---
 Project.toml       |  4 +++
 SimpleRayTracer.jl | 88 ++++++++++++++++++++++++++++++++++++++++++++++
 rt.jl              | 28 +++++++++++++++
 3 files changed, 120 insertions(+)
 create mode 100644 SimpleRayTracer.jl
 create mode 100644 rt.jl

diff --git a/Project.toml b/Project.toml
index 57447ab..2571e9f 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,11 +1,15 @@
 [deps]
+BenchmarkTools = "6e4b80f9-dd63-53aa-95a3-0cdb28fa8baf"
+Colors = "5ae59095-9a9b-59fe-a467-6f913c188581"
 CondaPkg = "992eb4ea-22a4-4c89-a5bb-47a3300528ab"
 GLMakie = "e9467ef8-e4e7-5192-8a1a-b1aee30e663a"
+GeometryBasics = "5c1252a2-5f33-56bf-86c9-59e7332b4326"
 ImageView = "86fae568-95e7-573e-a6b2-d8a6b900c9ef"
 Images = "916415d5-f1e6-5110-898d-aaa5f9f070e0"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 PythonCall = "6099a3de-0909-46bc-b1f4-468b9a2dfc0d"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
+Rotations = "6038ab10-8711-5258-84ad-4b1120ba62dc"
 StackViews = "cae243ae-269e-4f55-b966-ac2d0dc13c15"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
diff --git a/SimpleRayTracer.jl b/SimpleRayTracer.jl
new file mode 100644
index 0000000..c32d879
--- /dev/null
+++ b/SimpleRayTracer.jl
@@ -0,0 +1,88 @@
+module SimpleRayTracer
+
+using LinearAlgebra
+using Images
+using GeometryBasics
+using Rotations
+
+export OrthogonalCamera
+export World, Ray
+export Sphere
+
+abstract type AbstractCamera end
+abstract type AbstractObject end
+
+struct OrthogonalCamera{T<:AbstractFloat} <: AbstractCamera
+    origin::Vec3{T}
+    rotation::RotXYZ{T}
+    size::Tuple{T, T}
+    # function OrthogonalCamera(o, θ, s)
+    #     new(o, RotXYZ(0.0, 0.0, 0.0), s)
+    # end
+end
+
+function get_rays(camera::OrthogonalCamera, resolution::Tuple{I, I}) where {I<:Integer}
+    X, Y = camera.size
+    rx, ry = resolution
+    origins = [Vec3(x, y, 0.0) + camera.origin for x = LinRange(-X, X, rx), y = LinRange(-Y, Y, ry)]
+    [Ray(o, Vec3(0.0, 0.0, 1.0)) for o in origins]
+end
+
+struct Ray{T<:AbstractFloat}
+    origin::Vec3{T}
+    direction::Vec3{T}
+    # function Ray{T}(o, d) where {T<:AbstractFloat}
+    #     new(o, d |> normalize)
+    # end
+end
+
+struct HitInfo
+    hit::Bool
+    color::RGB{N0f8}
+end
+
+struct World
+    objects::Vector
+    background::RGB{N0f8}
+    function World(color)
+        new([], color)
+    end
+end
+
+Base.push!(w::World, x::AbstractObject) = push!(w.objects, x)
+
+struct Sphere{T<:AbstractFloat} <: AbstractObject
+    origin::Vec3{T}
+    radius::T
+    color::RGB{N0f8}
+end
+
+function check_hit(ray::Ray{T}, sphere::Sphere{T})::Tuple{Bool, T} where {T <: AbstractFloat}
+    p = ray.origin - sphere.origin
+    a = dot(ray.direction, ray.direction)
+    b = 2 * dot(p, ray.direction)
+    c = dot(p, p) - sphere.radius^2
+    Δ = b^2 - 4a*c
+    Δ < 0.0 && return false, -1.0
+    x, z = -b/(2a), √Δ/(2a)
+    t = x - z
+    t = t < eps() ? x + z : t
+    return t < eps() ? (false, -1.0) : (true, t)
+end
+
+function trace_ray(world::World, ray::Ray)::HitInfo
+    mindist = Float64 |> typemax |> prevfloat
+    hit = false
+    color = world.background
+    for obj in world.objects
+        hit, dist = check_hit(ray, obj)
+        if hit && dist < mindist
+            mindist = dist
+            hit = true
+            color = obj.color
+        end
+    end
+    return HitInfo(hit, color)
+end
+
+end
diff --git a/rt.jl b/rt.jl
new file mode 100644
index 0000000..864a443
--- /dev/null
+++ b/rt.jl
@@ -0,0 +1,28 @@
+using BenchmarkTools
+using LinearAlgebra
+using Rotations
+
+# using Images
+using Colors
+using GLMakie
+
+##
+include("SimpleRayTracer.jl")
+
+world = SimpleRayTracer.World(RGB(.1,.5,.5))
+push!(world, SimpleRayTracer.Sphere(Vec3(-2.5,  0.0, 0.0), 2.0, RGB(1, 0, 0)))
+push!(world, SimpleRayTracer.Sphere(Vec3( 2.5,  0.0, 0.0), 2.0, RGB(0, 1, 0)))
+push!(world, SimpleRayTracer.Sphere(Vec3( 0.0,  0.0, 2.5), 2.0, RGB(0, 0, 1)))
+
+camera = SimpleRayTracer.OrthogonalCamera(
+    Vec3(0.0, 0.0, -5.0),
+    RotXYZ(0.0, 0.0, 0.0),
+    (5.0, 5.0)
+)
+
+resolution = (256, 256)
+img = [SimpleRayTracer.trace_ray(world, ray).color for ray in SimpleRayTracer.get_rays(camera, resolution)];
+
+fig = Figure(size=resolution)
+ax = Axis(fig[1,1], aspect=1)
+image!(ax, img)