From 523f9439ed0d2e4c2d51edc623b6c4d62885cfdd Mon Sep 17 00:00:00 2001
From: Nat Lasseter <user@4574.co.uk>
Date: Wed, 12 Jun 2024 23:19:56 +0100
Subject: Finished chapter 9

---
 lib/vec3.rb | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

(limited to 'lib/vec3.rb')

diff --git a/lib/vec3.rb b/lib/vec3.rb
index e24229a..08cbf69 100644
--- a/lib/vec3.rb
+++ b/lib/vec3.rb
@@ -87,12 +87,28 @@ class Colour < Vec3
   def g; @y; end
   def b; @z; end
 
+  def gamma(gma = 2)
+    Colour.new(
+      r > 0 ? r ** (1.0 / gma) : r,
+      g > 0 ? g ** (1.0 / gma) : g,
+      b > 0 ? b ** (1.0 / gma) : b
+    )
+  end
+
+  def clamp(interval)
+    Colour.new(
+      interval.clamp(r),
+      interval.clamp(g),
+      interval.clamp(b)
+    )
+  end
+
   def to_ppm
-    intensity = Interval.new(0.0, 0.999)
+    g_space = gamma.clamp(Interval.new(0.0, 0.999))
     "%3d %3d %3d" % [
-      (intensity.clamp(r) * 256).to_i,
-      (intensity.clamp(g) * 256).to_i,
-      (intensity.clamp(b) * 256).to_i
+      (g_space.r * 256).to_i,
+      (g_space.g * 256).to_i,
+      (g_space.b * 256).to_i
     ]
   end
 end
-- 
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