Book 3 listg 30: mixture_pdf needs shared_ptr args

Resolves #608

Author: hollasch

CHANGELOG.md

@@ -7,6 +7,7 @@ Change Log -- Ray Tracing in One Weekend
   - 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 30, `mixture_pdf` needs `shared_ptr` arguments (#608)
 
 
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books/RayTracingTheRestOfYourLife.html

@@ -1800,10 +1800,10 @@
 
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
         shared_ptr<hittable> light_ptr = make_shared<xz_rect>(213, 343, 227, 332, 554, 0);
-        hittable_pdf p0(light_ptr, rec.p);
 
-        cosine_pdf p1(rec.normal);
-        mixture_pdf p(&p0, &p1);
+        auto p0 = make_shared<hittable_pdf>(light_ptr, rec.p);
+        auto p1 = make_shared<cosine_pdf>(rec.normal);
+        mixture_pdf p(p0, p1);
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
 
         scattered = ray(rec.p, p.generate(), r.time());