add tonemapping and scene

Author: SimonDanisch

docs/code/basic-scene.jl

@@ -0,0 +1,119 @@
+using GeometryBasics
+using Trace
+using FileIO
+using ImageCore
+using BenchmarkTools
+using Makie, FileIO, ImageShow
+
+
+catmesh = load(Makie.assetpath("cat.obj"))
+img = load(Makie.assetpath("diffusemap.png"))
+m = normal_mesh(Tesselation(Sphere(Point3f(0), 1), 32))
+
+function tmesh(prim, material)
+    prim =  prim isa Sphere ? Tesselation(prim, 64) : prim
+    mesh = normal_mesh(prim)
+    triangles = Trace.create_triangle_mesh(mesh, Trace.ShapeCore())
+    return [Trace.GeometricPrimitive(t, material) for t in triangles]
+end
+
+material_red = Trace.MatteMaterial(
+    Trace.ConstantTexture(Trace.RGBSpectrum(0.796f0, 0.235f0, 0.2f0)),
+    Trace.ConstantTexture(0.0f0),
+)
+material_blue = Trace.MatteMaterial(
+    Trace.ConstantTexture(Trace.RGBSpectrum(0.251f0, 0.388f0, 0.847f0)),
+    Trace.ConstantTexture(0.0f0),
+)
+material_white = Trace.MatteMaterial(
+    Trace.ConstantTexture(Trace.RGBSpectrum(1.0f0)),
+    Trace.ConstantTexture(0.0f0),
+)
+mirror = Trace.MirrorMaterial(Trace.ConstantTexture(Trace.RGBSpectrum(1.0f0)))
+glass = Trace.GlassMaterial(
+    Trace.ConstantTexture(Trace.RGBSpectrum(1.0f0)),
+    Trace.ConstantTexture(Trace.RGBSpectrum(1.0f0)),
+    Trace.ConstantTexture(0.0f0),
+    Trace.ConstantTexture(0.0f0),
+    Trace.ConstantTexture(1.5f0),
+    true,
+)
+
+LowSphere(radius, contact=Point3f(0)) = Sphere(contact .+ Point3f(0, 0, radius), radius)
+
+begin
+    s1 = tmesh(LowSphere(0.5f0), material_white)
+    s2 = tmesh(LowSphere(0.3f0, Point3f(0.5, 0.5, 0)), material_blue)
+    s3 = tmesh(LowSphere(0.3f0, Point3f(-0.5, 0.5, 0)), mirror)
+    s4 = tmesh(LowSphere(0.4f0, Point3f(0.0, 1.0, 0)), material_white)
+    ground = tmesh(Rect3f(Vec3f(-5, -5, 0), Vec3f(10, 10, -0.1)), mirror)
+    left = tmesh(Rect3f(Vec3f(-3, 0, 0), Vec3f(-0.1, 10, -0.1)), mirror)
+
+    bvh = Trace.BVHAccel([s1..., s2..., s3..., s4..., ground...], 1);
+
+    lights = [
+        Trace.PointLight(Vec3f(0, 2.5, 4), Trace.RGBSpectrum(60.0f0)),
+        Trace.PointLight(Vec3f(-5, 2, 0), Trace.RGBSpectrum(60.0f0)),
+    ]
+    scene = Trace.Scene(lights, bvh);
+    resolution = Point2f(1024)
+    f = Trace.LanczosSincFilter(Point2f(1.0f0), 3.0f0)
+    film = Trace.Film(resolution,
+        Trace.Bounds2(Point2f(0.0f0), Point2f(1.0f0)),
+        f, 1.0f0, 1.0f0,
+        "shadows_sppm_res.png",
+    )
+    screen_window = Trace.Bounds2(Point2f(-1), Point2f(1))
+    camera = Trace.PerspectiveCamera(
+        Trace.look_at(Point3f(0, 3, 3), Point3f(0, 0, 0), Vec3f(0, 0, 1)),
+        screen_window, 0.0f0, 1.0f0, 0.0f0, 1.0f6, 45.0f0, film,
+    )
+    integrator = Trace.WhittedIntegrator(camera, Trace.UniformSampler(8), 1)
+    integrator(scene)
+    img = reverse(film.framebuffer, dims=1)
+end
+x = Trace.scale(2, 2, 2)
+x.inv_m == inv(x.m)
+GLMakie.activate!(inline=true)
+# Computer projective camera transformations.
+resolution = Point2f(1024)
+resolution = Trace.scale(resolution[1], resolution[2], 1)
+
+window_width = screen_window.p_max .- screen_window.p_min
+inv_bounds = Trace.scale((1.0f0 ./ window_width)..., 1)
+
+offset = Trace.translate(Vec3f(
+    -screen_window.p_min..., 0.0f0,
+))
+
+ray = camera.core.raster_to_camera(Point3f(1024 / 2, 1024 / 2, 0))
+camera.core.screen_to_raster(camera.core.camera_to_screen(ray))
+
+camera.core.screen_to_raster(Point3f(-1, -1, 0))
+camera.core.screen_to_raster(Point3f(1, 1, 0))
+
+camera.core.raster_to_screen(Point3f(1024, 1024, 0))
+
+camera.core.screen_to_raster(Point3f(-1, -1, 0))# == (0, 0, 0)
+camera.core.screen_to_raster(Point3f(1, 1, 0))# == (1024, 1024, 0)
+
+camera.core.raster_to_screen(Point3f(0, 0, 0)) # == (0, 0, 0)
+camera.core.screen_to_raster(Point3f(1, 1, 0)) # == (1024, 1024, 0)
+
+
+res_t = Trace.scale(resolution..., 1)
+window_width = screen_window.p_max .- screen_window.p_min
+inv_bounds = Trace.scale((1f0 ./ window_width)..., 1)
+
+offset = Trace.translate(Vec3f(
+    (-screen_window.p_min)..., 0f0,
+))
+
+inv(res_t.m)
+screen_to_raster = res_t * inv_bounds * offset
+
+screen_to_raster(Point3f(1, 1, 0))
+
+raster_to_screen = inv(offset) *  inv(inv_bounds) * inv(res_t)
+
+raster_to_screen(Point3f(1024, 1024, 0))

src/materials/tonemap.jl

@@ -0,0 +1,58 @@
+using Colors, Statistics
+
+luminosity(c::RGB{T}) where {T} = (max(c.r, c.g, c.b) + min(c.r, c.g, c.b)) / 2.0
+
+function lum_max(rgb_m)
+    lum_max = 0.0
+    for pix in rgb_m
+        (lum_max > luminosity(pix)) || (lum_max = luminosity(pix))
+    end
+    lum_max
+end
+
+function avg_lum(rgb_m, δ::Number=1e-10)
+    cumsum = 0.0
+    for pix in rgb_m
+        cumsum += log10(δ + luminosity(pix))
+    end
+    return 10^(cumsum / (prod(size(rgb_m))))
+end
+
+function normalize_image(
+        rgb_m,
+        a::Float64=0.18,
+        lum::Union{Number,Nothing}=nothing,
+        δ::Number=1e-10
+    )
+
+    (isnothing(lum) || lum ≈ 0.0) && (lum = avg_lum(rgb_m, δ))
+    return rgb_m .* a .* (1.0 / lum)
+end
+
+function clamp_image(img::AbstractMatrix{T}) where {T}
+    return map(img) do col
+        return T(clamp(col.r, 0, 1), clamp(col.g, 0, 1), clamp(col.b, 0, 1))
+    end
+end
+
+function γ_correction(img::AbstractMatrix{T}, γ::Float64=1.0, k::Float64=1.0) where T
+    return map(img) do c
+        return T(
+            floor(255 * c.r^(1 / γ)),
+            floor(255 * c.g^(1 / γ)),
+            floor(255 * c.b^(1 / γ))
+        )
+    end
+end
+
+function tone_mapping(img;
+        a::Float64=0.18,
+        γ::Float64=1.0,
+        lum::Union{Number,Nothing}=nothing
+    )
+    img = normalize_image(img, a, lum)
+    img = clamp_image(img)
+    return γ_correction(img, γ)
+end
+
+tone_mapping(img)