Completed the move to removing flipface from book 2, and added its source into the text of book 3

Author: trevordblack

CHANGELOG.md

@@ -11,7 +11,7 @@ Change Log -- Ray Tracing in One Weekend
 
 ### _The Next Week_
   - Removed: Deleted the section covering the old `flip_face` class, renumbered images as this
-    eliminated the rendering with missing Cornell box faces (#482)
+    eliminated the rendering with missing Cornell box faces (#482, #661)
   - Change: Renamed and explicitly numbered book images and figures (#495)
   - Fix: Reduced code duplication in dielectric::scatter() function
   - New: Added alternative constructors that take color arguments in addition to the constructors

books/RayTracingTheRestOfYourLife.html

@@ -1493,7 +1493,56 @@
 </div>
 
 <div class='together'>
-We also need to flip the light so its normals point in the -y direction. This gives us:
+We also need to flip the light so its normals point in the $-y$ direction:
+
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
+    class flip_face : public hittable {
+        public:
+            flip_face(shared_ptr<hittable> p) : ptr(p) {}
+
+            virtual bool hit(const ray& r, double t_min, double t_max, hit_record& rec) const {
+                if (!ptr->hit(r, t_min, t_max, rec))
+                    return false;
+
+                rec.front_face = !rec.front_face;
+                return true;
+            }
+
+            virtual bool bounding_box(double t0, double t1, aabb& output_box) const {
+                return ptr->bounding_box(t0, t1, output_box);
+            }
+
+        public:
+            shared_ptr<hittable> ptr;
+    };
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    [Listing [flip-face]: <kbd>[hittable.h]</kbd> We use a hittable object to flip the light]
+
+Making sure to call this in our world definition:
+
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
+    hittable_list cornell_box() {
+        hittable_list world;
+
+        auto red   = make_shared<lambertian>(color(.65, .05, .05));
+        auto white = make_shared<lambertian>(color(.73, .73, .73));
+        auto green = make_shared<lambertian>(color(.12, .45, .15));
+        auto light = make_shared<diffuse_light>(color(15, 15, 15));
+
+        world.add(make_shared<yz_rect>(0, 555, 0, 555, 555, green));
+        world.add(make_shared<yz_rect>(0, 555, 0, 555, 0, red));
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
+        world.add(make_shared<flip_face>(make_shared<xz_rect>(213, 343, 227, 332, 554, light)));
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
+        world.add(make_shared<xz_rect>(0, 555, 0, 555, 555, white));
+        world.add(make_shared<xz_rect>(0, 555, 0, 555, 0, white));
+        world.add(make_shared<xy_rect>(0, 555, 0, 555, 555, white));
+
+        ...
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    [Listing [flipping-light]: <kbd>[main.cc]</kbd> Flip the light in our cornell box scene]
+
+This gives us:
 
   ![Image 5: Cornell box, light emitted only in the downward direction
   ](../images/img-3.05-cornell-lightdown.jpg class=pixel)

src/TheNextWeek/box.h

@@ -41,16 +41,13 @@ box::box(const point3& p0, const point3& p1, shared_ptr<material> ptr) {
     box_max = p1;
 
     sides.add(make_shared<xy_rect>(p0.x(), p1.x(), p0.y(), p1.y(), p1.z(), ptr));
-    sides.add(make_shared<flip_face>(
-        make_shared<xy_rect>(p0.x(), p1.x(), p0.y(), p1.y(), p0.z(), ptr)));
+    sides.add(make_shared<xy_rect>(p0.x(), p1.x(), p0.y(), p1.y(), p0.z(), ptr));
 
     sides.add(make_shared<xz_rect>(p0.x(), p1.x(), p0.z(), p1.z(), p1.y(), ptr));
-    sides.add(make_shared<flip_face>(
-        make_shared<xz_rect>(p0.x(), p1.x(), p0.z(), p1.z(), p0.y(), ptr)));
+    sides.add(make_shared<xz_rect>(p0.x(), p1.x(), p0.z(), p1.z(), p0.y(), ptr));
 
     sides.add(make_shared<yz_rect>(p0.y(), p1.y(), p0.z(), p1.z(), p1.x(), ptr));
-    sides.add(make_shared<flip_face>(
-        make_shared<yz_rect>(p0.y(), p1.y(), p0.z(), p1.z(), p0.x(), ptr)));
+    sides.add(make_shared<yz_rect>(p0.y(), p1.y(), p0.z(), p1.z(), p0.x(), ptr));
 }
 
 bool box::hit(const ray& r, double t0, double t1, hit_record& rec) const {

src/TheNextWeek/hittable.h

@@ -40,28 +40,6 @@ class hittable {
         virtual bool bounding_box(double t0, double t1, aabb& output_box) const = 0;
 };
 
-
-class flip_face : public hittable {
-    public:
-        flip_face(shared_ptr<hittable> p) : ptr(p) {}
-
-        virtual bool hit(const ray& r, double t_min, double t_max, hit_record& rec) const {
-            if (!ptr->hit(r, t_min, t_max, rec))
-                return false;
-
-            rec.front_face = !rec.front_face;
-            return true;
-        }
-
-        virtual bool bounding_box(double t0, double t1, aabb& output_box) const {
-            return ptr->bounding_box(t0, t1, output_box);
-        }
-
-    public:
-        shared_ptr<hittable> ptr;
-};
-
-
 class translate : public hittable {
     public:
         translate(shared_ptr<hittable> p, const vec3& displacement)

src/TheNextWeek/main.cc

@@ -152,12 +152,12 @@ hittable_list cornell_box() {
     auto green = make_shared<lambertian>(color(.12, .45, .15));
     auto light = make_shared<diffuse_light>(color(15,15,15));
 
-    objects.add(make_shared<flip_face>(make_shared<yz_rect>(0, 555, 0, 555, 555, green)));
+    objects.add(make_shared<yz_rect>(0, 555, 0, 555, 555, green));
     objects.add(make_shared<yz_rect>(0, 555, 0, 555, 0, red));
     objects.add(make_shared<xz_rect>(213, 343, 227, 332, 554, light));
-    objects.add(make_shared<flip_face>(make_shared<xz_rect>(0, 555, 0, 555, 555, white)));
+    objects.add(make_shared<xz_rect>(0, 555, 0, 555, 555, white));
     objects.add(make_shared<xz_rect>(0, 555, 0, 555, 0, white));
-    objects.add(make_shared<flip_face>(make_shared<xy_rect>(0, 555, 0, 555, 555, white)));
+    objects.add(make_shared<xy_rect>(0, 555, 0, 555, 555, white));
 
     shared_ptr<hittable> box1 = make_shared<box>(point3(0,0,0), point3(165,330,165), white);
     box1 = make_shared<rotate_y>(box1,  15);
@@ -181,12 +181,12 @@ hittable_list cornell_balls() {
     auto green = make_shared<lambertian>(color(.12, .45, .15));
     auto light = make_shared<diffuse_light>(color(5, 5, 5));
 
-    objects.add(make_shared<flip_face>(make_shared<yz_rect>(0, 555, 0, 555, 555, green)));
+    objects.add(make_shared<yz_rect>(0, 555, 0, 555, 555, green));
     objects.add(make_shared<yz_rect>(0, 555, 0, 555, 0, red));
     objects.add(make_shared<xz_rect>(113, 443, 127, 432, 554, light));
-    objects.add(make_shared<flip_face>(make_shared<xz_rect>(0, 555, 0, 555, 555, white)));
+    objects.add(make_shared<xz_rect>(0, 555, 0, 555, 555, white));
     objects.add(make_shared<xz_rect>(0, 555, 0, 555, 0, white));
-    objects.add(make_shared<flip_face>(make_shared<xy_rect>(0, 555, 0, 555, 555, white)));
+    objects.add(make_shared<xy_rect>(0, 555, 0, 555, 555, white));
 
     auto boundary = make_shared<sphere>(point3(160,100,145), 100, make_shared<dielectric>(1.5));
     objects.add(boundary);
@@ -209,12 +209,12 @@ hittable_list cornell_smoke() {
     auto green = make_shared<lambertian>(color(.12, .45, .15));
     auto light = make_shared<diffuse_light>(color(7, 7, 7));
 
-    objects.add(make_shared<flip_face>(make_shared<yz_rect>(0, 555, 0, 555, 555, green)));
+    objects.add(make_shared<yz_rect>(0, 555, 0, 555, 555, green));
     objects.add(make_shared<yz_rect>(0, 555, 0, 555, 0, red));
     objects.add(make_shared<xz_rect>(113, 443, 127, 432, 554, light));
-    objects.add(make_shared<flip_face>(make_shared<xz_rect>(0, 555, 0, 555, 555, white)));
+    objects.add(make_shared<xz_rect>(0, 555, 0, 555, 555, white));
     objects.add(make_shared<xz_rect>(0, 555, 0, 555, 0, white));
-    objects.add(make_shared<flip_face>(make_shared<xy_rect>(0, 555, 0, 555, 555, white)));
+    objects.add(make_shared<xy_rect>(0, 555, 0, 555, 555, white));
 
     shared_ptr<hittable> box1 = make_shared<box>(point3(0,0,0), point3(165,330,165), white);
     box1 = make_shared<rotate_y>(box1,  15);
@@ -243,12 +243,12 @@ hittable_list cornell_final() {
     auto green = make_shared<lambertian>(color(.12, .45, .15));
     auto light = make_shared<diffuse_light>(color(7, 7, 7));
 
-    objects.add(make_shared<flip_face>(make_shared<yz_rect>(0, 555, 0, 555, 555, green)));
+    objects.add(make_shared<yz_rect>(0, 555, 0, 555, 555, green));
     objects.add(make_shared<yz_rect>(0, 555, 0, 555, 0, red));
     objects.add(make_shared<xz_rect>(123, 423, 147, 412, 554, light));
-    objects.add(make_shared<flip_face>(make_shared<xz_rect>(0, 555, 0, 555, 555, white)));
+    objects.add(make_shared<xz_rect>(0, 555, 0, 555, 555, white));
     objects.add(make_shared<xz_rect>(0, 555, 0, 555, 0, white));
-    objects.add(make_shared<flip_face>(make_shared<xy_rect>(0, 555, 0, 555, 555, white)));
+    objects.add(make_shared<xy_rect>(0, 555, 0, 555, 555, white));
 
     shared_ptr<hittable> boundary2 =
         make_shared<box>(point3(0,0,0), point3(165,165,165), make_shared<dielectric>(1.5));

src/TheRestOfYourLife/box.h

@@ -41,16 +41,13 @@ box::box(const point3& p0, const point3& p1, shared_ptr<material> ptr) {
     box_max = p1;
 
     sides.add(make_shared<xy_rect>(p0.x(), p1.x(), p0.y(), p1.y(), p1.z(), ptr));
-    sides.add(make_shared<flip_face>(
-        make_shared<xy_rect>(p0.x(), p1.x(), p0.y(), p1.y(), p0.z(), ptr)));
+    sides.add(make_shared<xy_rect>(p0.x(), p1.x(), p0.y(), p1.y(), p0.z(), ptr));
 
     sides.add(make_shared<xz_rect>(p0.x(), p1.x(), p0.z(), p1.z(), p1.y(), ptr));
-    sides.add(make_shared<flip_face>(
-        make_shared<xz_rect>(p0.x(), p1.x(), p0.z(), p1.z(), p0.y(), ptr)));
+    sides.add(make_shared<xz_rect>(p0.x(), p1.x(), p0.z(), p1.z(), p0.y(), ptr));
 
     sides.add(make_shared<yz_rect>(p0.y(), p1.y(), p0.z(), p1.z(), p1.x(), ptr));
-    sides.add(make_shared<flip_face>(
-        make_shared<yz_rect>(p0.y(), p1.y(), p0.z(), p1.z(), p0.x(), ptr)));
+    sides.add(make_shared<yz_rect>(p0.y(), p1.y(), p0.z(), p1.z(), p0.x(), ptr));
 }
 
 bool box::hit(const ray& r, double t0, double t1, hit_record& rec) const {

src/TheRestOfYourLife/main.cc

@@ -70,12 +70,12 @@ hittable_list cornell_box() {
     auto green = make_shared<lambertian>(color(.12, .45, .15));
     auto light = make_shared<diffuse_light>(color(15, 15, 15));
 
-    world.add(make_shared<flip_face>(make_shared<yz_rect>(0, 555, 0, 555, 555, green)));
+    world.add(make_shared<yz_rect>(0, 555, 0, 555, 555, green));
     world.add(make_shared<yz_rect>(0, 555, 0, 555, 0, red));
     world.add(make_shared<flip_face>(make_shared<xz_rect>(213, 343, 227, 332, 554, light)));
-    world.add(make_shared<flip_face>(make_shared<xz_rect>(0, 555, 0, 555, 555, white)));
+    world.add(make_shared<xz_rect>(0, 555, 0, 555, 555, white));
     world.add(make_shared<xz_rect>(0, 555, 0, 555, 0, white));
-    world.add(make_shared<flip_face>(make_shared<xy_rect>(0, 555, 0, 555, 555, white)));
+    world.add(make_shared<xy_rect>(0, 555, 0, 555, 555, white));
 
     shared_ptr<hittable> box1 = make_shared<box>(point3(0,0,0), point3(165,330,165), white);
     box1 = make_shared<rotate_y>(box1, 15);