From 3549acb5dbd2f6fe43be6cce9828785ccead7e77 Mon Sep 17 00:00:00 2001
From: Nat Lasseter <user@4574.co.uk>
Date: Fri, 14 Jun 2024 12:23:49 +0100
Subject: Finished! Good god performance nope.

---
 lib/camera.rb   | 25 +++++++++++++++++++------
 lib/hittable.rb |  4 ++--
 lib/material.rb | 17 +++++++----------
 lib/vec3.rb     | 27 +++++++++++++++------------
 4 files changed, 43 insertions(+), 30 deletions(-)

(limited to 'lib')

diff --git a/lib/camera.rb b/lib/camera.rb
index 365ebcd..3ddf769 100644
--- a/lib/camera.rb
+++ b/lib/camera.rb
@@ -3,7 +3,8 @@ class Camera
                  aliasing: 10, depth: 10, vfov: 90.0,
                  lookfrom: Point.new(0, 0, 0),
                  lookat: Point.new(0, 0, -1),
-                 vup: Vec3.new(0, 1, 0))
+                 vup: Vec3.new(0, 1, 0),
+                 defocus_angle: 0, focus_dist: 10)
     @width = width
     @aliasing = aliasing
     @depth = depth
@@ -14,13 +15,12 @@ class Camera
 
     # Camera
     @c_centre = lookfrom
-    c_focallength = (lookfrom - lookat).mag
 
     # Viewport
     theta = vfov * Maths::PI / 180
     h = Maths.tan(theta / 2)
-    v_height = 2.0 * h * c_focallength
-    v_width = v_height * @width.to_f / @height
+    v_height = 2.0 * h * focus_dist
+    v_width = (v_height * @width) / @height
 
     # Camera basis vectors
     w = (lookfrom - lookat).unit
@@ -36,8 +36,14 @@ class Camera
 
     # Upper left pixel
     v_upperleft = @c_centre - v_u / 2 - v_v / 2 -
-                  w * c_focallength
+                  w * focus_dist
     @p00_loc = v_upperleft + (@pd_u + @pd_v) / 2
+
+    @defocus_angle = defocus_angle
+    defocus_radius = focus_dist * Maths.tan((@defocus_angle / 2) *
+                                            Maths::PI / 180)
+    @defocus_disk_u = u * defocus_radius
+    @defocus_disk_v = v * defocus_radius
   end
 
   def render(world)
@@ -70,6 +76,13 @@ class Camera
                @pd_u * (col + rand - 0.5) +
                @pd_v * (row + rand - 0.5)
 
-    Ray.new(@c_centre, p_sample - @c_centre)
+    ray_origin = @defocus_angle <= 0 ? @c_centre : defocus_disk_sample
+    ray_dir = p_sample - ray_origin
+    Ray.new(ray_origin, ray_dir)
+  end
+
+  def defocus_disk_sample
+    p = Vec3.random_in_unit(dimensions: 2)
+    @c_centre + @defocus_disk_u * p.x + @defocus_disk_v * p.y
   end
 end
diff --git a/lib/hittable.rb b/lib/hittable.rb
index 2a433d8..1e22613 100644
--- a/lib/hittable.rb
+++ b/lib/hittable.rb
@@ -45,8 +45,8 @@ class Hittables < Hittable
 end
 
 class Sphere < Hittable
-  def initialize(ox, oy, oz, radius = 1, material)
-    @centre = Point.new(ox, oy, oz)
+  def initialize(centre, radius = 1, material)
+    @centre = centre
     @radius = radius
     @material = material
   end
diff --git a/lib/material.rb b/lib/material.rb
index 752b85f..14eb5f9 100644
--- a/lib/material.rb
+++ b/lib/material.rb
@@ -1,6 +1,6 @@
 class Material
-  def initialize(r, g, b)
-    @albedo = Colour.new(r, g, b)
+  def initialize(albedo)
+    @albedo = albedo
   end
 
   def attenuation
@@ -14,21 +14,21 @@ end
 
 class Lambertian < Material
   def scatter(ray, record)
-    scat = record.normal + Vec3.random_unit
+    scat = record.normal + Vec3.random_in_unit
     scat = rec.normal if scat.near_zero?
     Ray.new(record.point, scat)
   end
 end
 
 class Metal < Material
-  def initialize(r, g, b, fuzz)
+  def initialize(albedo, fuzz)
     @fuzz = fuzz < 1 ? fuzz : 1
-    super(r, g, b)
+    super(albedo)
   end
 
   def scatter(ray, record)
     refl = ray.direction.reflect(record.normal)
-    refl = refl.unit + (Vec3.random_unit * @fuzz)
+    refl = refl.unit + (Vec3.random_in_unit * @fuzz)
     if refl.dot(record.normal) > 0
       Ray.new(record.point, refl)
     else
@@ -40,10 +40,7 @@ end
 class Dielectric < Material
   def initialize(ref_index)
     @ref_index = ref_index
-  end
-
-  def attenuation
-    Colour.new(1.0, 1.0, 1.0)
+    super(Colour.new(1.0, 1.0, 1.0))
   end
 
   def scatter(ray, record)
diff --git a/lib/vec3.rb b/lib/vec3.rb
index 478fe4c..46d8ee1 100644
--- a/lib/vec3.rb
+++ b/lib/vec3.rb
@@ -1,8 +1,8 @@
 class Vec3
-  def initialize(x = 0, y = 0, z = 0)
-    @x = x.to_f
-    @y = y.to_f
-    @z = z.to_f
+  def initialize(x = 0.0, y = 0.0, z = 0.0)
+    @x = x
+    @y = y
+    @z = z
   end
 
   attr_reader :x, :y, :z
@@ -67,7 +67,7 @@ class Vec3
     rout_perp + rout_parr
   end
 
-  def in_unit_sphere?
+  def in_unit?
     mag_sqr < 1
   end
 
@@ -79,18 +79,21 @@ class Vec3
     "{#{@x}, #{@y}, #{@z}}"
   end
 
-  def self.random(min = 0, max = 1)
-    interval = Interval.new(min.to_f, max.to_f)
-    Vec3.new(interval.sample, interval.sample, interval.sample)
+  def self.random(min: -1.0, max: 1.0, dimensions: 3)
+    interval = Interval.new(min, max)
+    self.new(
+      dimensions >= 1 ? interval.sample : 0,
+      dimensions >= 2 ? interval.sample : 0,
+      dimensions >= 3 ? interval.sample : 0
+    )
   end
 
-  def self.random_unit(normal = nil)
+  def self.random_in_unit(normal: nil, dimensions: 3)
     p = nil
     while p.nil?
-      c = Vec3.random
-      p = c.unit if c.in_unit_sphere?
+      c = self.random(dimensions: dimensions)
+      p = c.unit if c.in_unit?
     end
-
     normal.nil? || p.dot(normal) > 0 ? p : -p
   end
 end
-- 
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