Incorporate review feedback.

Author: hollasch

books/RayTracingInOneWeekend.html

@@ -915,8 +915,12 @@
     #define HITTABLE_LIST_H
 
     #include "hittable.h"
+    #include <memory>
     #include <vector>
 
+    using std::shared_ptr;
+    using std::make_shared;
+
     class hittable_list: public hittable {
         public:
             hittable_list() {}
@@ -954,8 +958,8 @@
 
 ## Some New C++ Features
 
-This code uses two C++ features that may trip you up if you're not normally a C++ programmer:
-`vector` and `shared_ptr`.
+The `hittable_list` class code uses two C++ features that may trip you up if you're not normally a
+C++ programmer: `vector` and `shared_ptr`.
 
 `shared_ptr<type>` is a pointer to some allocated type, with reference-counting semantics.
 Every time you assign its value to another shared pointer (usually with a simple assignment), the
@@ -975,17 +979,25 @@
 arguments `(1, true)`. It returns a `shared_ptr<thing>`. This can be simplified as in the second
 line with the `auto` type declaration, because the type is sufficiently defined by the return type
 of `make_shared<thing2>`.
+</div>
 
 We'll use shared pointers in our code, because it allows multiple objects to use a common object
 (for example, a bunch of spheres that all use the same material), and because it makes memory
 management automatic and easier to reason about.
-</div>
+
+`std::shared_ptr` is included with the `<memory>` header.
 
 The second C++ feature you may be unfamiliar with is `std::vector`. This is a generic array-like
 collection of an arbitrary type. Above, we use a collection of pointers to `hittable`. `std::vector`
 automatically grows as more values are added: `objects.push_back(object)` adds a value to the end of
 the `std::vector` member variable `objects`.
 
+`std::vector` is included with the `<vector>` header.
+
+Finally, the `using` statements in listing [hittable-list-initial] tell the compiler that we'll be
+getting `shared_ptr` and `make_shared` from the `std` library, so we don't need to prefex these with
+`std::` every time we reference them.
+
 ## Common Constants and Utility Functions
 
 <div class='together'></div>
@@ -999,8 +1011,16 @@
     #ifndef RTWEEKEND_H
     #define RTWEEKEND_H
 
-    #include <limits>
     #include <cmath>
+    #include <cstdlib>
+    #include <limits>
+    #include <memory>
+
+
+    // Usings
+
+    using std::shared_ptr;
+    using std::make_shared;
 
     // Constants
 

books/RayTracingTheNextWeek.html

@@ -1078,9 +1078,11 @@
     };
 
     static double* perlin_generate() {
-        auto p = new double[perlin::point_count];
+        static double p[perlin::point_count];
+
         for (int i = 0; i < perlin::point_count; ++i)
             p[i] = random_double();
+
         return p;
     }
 

src/InOneWeekend/hittable_list.h

@@ -11,7 +11,9 @@
 // along with this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
 //==============================================================================================
 
+#include "common/rtweekend.h"
 #include "hittable.h"
+#include <memory>
 #include <vector>
 
 

src/TheNextWeek/hittable_list.h

@@ -11,6 +11,7 @@
 // along with this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
 //==============================================================================================
 
+#include "common/rtweekend.h"
 #include "hittable.h"
 #include <vector>
 

src/TheNextWeek/material.h

@@ -53,15 +53,15 @@ class dielectric : public material {
                 scattered = ray(rec.p, reflected, r_in.time());
                 return true;
             }
-            
+
             double reflect_prob = schlick(cos_theta, etai_over_etat);
             if (random_double() < reflect_prob)
             {
                 vec3 reflected = reflect(unit_direction, rec.normal);
                 scattered = ray(rec.p, reflected, r_in.time());
                 return true;
             }
-                
+
             vec3 refracted = refract(unit_direction, rec.normal, etai_over_etat);
             scattered = ray(rec.p, refracted, r_in.time());
             return true;

src/TheRestOfYourLife/hittable_list.h

@@ -11,6 +11,7 @@
 // along with this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
 //==============================================================================================
 
+#include "common/rtweekend.h"
 #include "hittable.h"
 #include <vector>
 

src/common/rtweekend.h

@@ -9,9 +9,9 @@
 // along with this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
 //==============================================================================================
 
+#include <cmath>
 #include <cstdlib>
 #include <limits>
-#include <cmath>
 #include <memory>