v3.1.2 (2020-06-03)

In One Weekend

• Fix: Correct typo: "Intance Translation" -> "Instance Translation"
• Fix: Corrected geometry type when computing distance between two points, final scene (#609)

The Rest of Your Life

• Fix: Missing closing parenthesis in listing 10 (#603)
• Fix: Tiny improvements to the lambertian::scatter() development (#604)
• Fix: Correct geometry type and unit vector method in ray_color(), listing 20 (#606)
• Fix: Listing 26: alternate random_double() switched distribution, generator (#621)
• Fix: Listing 28, 30: light_shape should have default material, not 0 (#607)
• Fix: Listing 30: mixture_pdf needs shared_ptr arguments (#608)