Remove unused operator<< & const-medium debug code

When I created issue #1495, I must have been in the middle of a code
progression, because it appeared to me that vec3::operator<< was unused.

Turns out it _is_ used, in debug code for the `constant_medium::hit()`
function. This code was created as a clean-up for the original scattered
debug statements in this function. On review, however, this appears a
bit odd, as the text does not mention the debuggability option (it's
off by default), and no other code in the books has debug print code.

Looking at it again, I think it should be removed, and readers are free
to add whatever debug code they need at any stage in development.

Resolves #1495

Author: hollasch

books/RayTracingTheNextWeek.html

@@ -4044,10 +4044,6 @@
         {}
 
         bool hit(const ray& r, interval ray_t, hit_record& rec) const override {
-            // Print occasional samples when debugging. To enable, set enableDebug true.
-            const bool enableDebug = false;
-            const bool debugging = enableDebug && random_double() < 0.00001;
-
             hit_record rec1, rec2;
 
             if (!boundary->hit(r, interval::universe, rec1))
@@ -4056,8 +4052,6 @@
             if (!boundary->hit(r, interval(rec1.t+0.0001, infinity), rec2))
                 return false;
 
-            if (debugging) std::clog << "\nt_min=" << rec1.t << ", t_max=" << rec2.t << '\n';
-
             if (rec1.t < ray_t.min) rec1.t = ray_t.min;
             if (rec2.t > ray_t.max) rec2.t = ray_t.max;
 
@@ -4077,12 +4071,6 @@
             rec.t = rec1.t + hit_distance / ray_length;
             rec.p = r.at(rec.t);
 
-            if (debugging) {
-                std::clog << "hit_distance = " <<  hit_distance << '\n'
-                          << "rec.t = " <<  rec.t << '\n'
-                          << "rec.p = " <<  rec.p << '\n';
-            }
-
             rec.normal = vec3(1,0,0);  // arbitrary
             rec.front_face = true;     // also arbitrary
             rec.mat = phase_function;

src/InOneWeekend/vec3.h

@@ -73,10 +73,6 @@ using point3 = vec3;
 
 // Vector Utility Functions
 
-inline std::ostream& operator<<(std::ostream& out, const vec3& v) {
-    return out << v.e[0] << ' ' << v.e[1] << ' ' << v.e[2];
-}
-
 inline vec3 operator+(const vec3& u, const vec3& v) {
     return vec3(u.e[0] + v.e[0], u.e[1] + v.e[1], u.e[2] + v.e[2]);
 }

src/TheNextWeek/constant_medium.h

@@ -31,10 +31,6 @@ class constant_medium : public hittable {
     {}
 
     bool hit(const ray& r, interval ray_t, hit_record& rec) const override {
-        // Print occasional samples when debugging. To enable, set enableDebug true.
-        const bool enableDebug = false;
-        const bool debugging = enableDebug && random_double() < 0.00001;
-
         hit_record rec1, rec2;
 
         if (!boundary->hit(r, interval::universe, rec1))
@@ -43,8 +39,6 @@ class constant_medium : public hittable {
         if (!boundary->hit(r, interval(rec1.t+0.0001, infinity), rec2))
             return false;
 
-        if (debugging) std::clog << "\nt_min=" << rec1.t << ", t_max=" << rec2.t << '\n';
-
         if (rec1.t < ray_t.min) rec1.t = ray_t.min;
         if (rec2.t > ray_t.max) rec2.t = ray_t.max;
 
@@ -64,12 +58,6 @@ class constant_medium : public hittable {
         rec.t = rec1.t + hit_distance / ray_length;
         rec.p = r.at(rec.t);
 
-        if (debugging) {
-            std::clog << "hit_distance = " <<  hit_distance << '\n'
-                      << "rec.t = " <<  rec.t << '\n'
-                      << "rec.p = " <<  rec.p << '\n';
-        }
-
         rec.normal = vec3(1,0,0);  // arbitrary
         rec.front_face = true;     // also arbitrary
         rec.mat = phase_function;

src/TheNextWeek/vec3.h

@@ -73,10 +73,6 @@ using point3 = vec3;
 
 // Vector Utility Functions
 
-inline std::ostream& operator<<(std::ostream& out, const vec3& v) {
-    return out << v.e[0] << ' ' << v.e[1] << ' ' << v.e[2];
-}
-
 inline vec3 operator+(const vec3& u, const vec3& v) {
     return vec3(u.e[0] + v.e[0], u.e[1] + v.e[1], u.e[2] + v.e[2]);
 }

src/TheRestOfYourLife/constant_medium.h

@@ -31,10 +31,6 @@ class constant_medium : public hittable {
     {}
 
     bool hit(const ray& r, interval ray_t, hit_record& rec) const override {
-        // Print occasional samples when debugging. To enable, set enableDebug true.
-        const bool enableDebug = false;
-        const bool debugging = enableDebug && random_double() < 0.00001;
-
         hit_record rec1, rec2;
 
         if (!boundary->hit(r, interval::universe, rec1))
@@ -43,8 +39,6 @@ class constant_medium : public hittable {
         if (!boundary->hit(r, interval(rec1.t+0.0001, infinity), rec2))
             return false;
 
-        if (debugging) std::clog << "\nt_min=" << rec1.t << ", t_max=" << rec2.t << '\n';
-
         if (rec1.t < ray_t.min) rec1.t = ray_t.min;
         if (rec2.t > ray_t.max) rec2.t = ray_t.max;
 
@@ -64,12 +58,6 @@ class constant_medium : public hittable {
         rec.t = rec1.t + hit_distance / ray_length;
         rec.p = r.at(rec.t);
 
-        if (debugging) {
-            std::clog << "hit_distance = " <<  hit_distance << '\n'
-                      << "rec.t = " <<  rec.t << '\n'
-                      << "rec.p = " <<  rec.p << '\n';
-        }
-
         rec.normal = vec3(1,0,0);  // arbitrary
         rec.front_face = true;     // also arbitrary
         rec.mat = phase_function;

src/TheRestOfYourLife/vec3.h

@@ -73,10 +73,6 @@ using point3 = vec3;
 
 // Vector Utility Functions
 
-inline std::ostream& operator<<(std::ostream& out, const vec3& v) {
-    return out << v.e[0] << ' ' << v.e[1] << ' ' << v.e[2];
-}
-
 inline vec3 operator+(const vec3& u, const vec3& v) {
     return vec3(u.e[0] + v.e[0], u.e[1] + v.e[1], u.e[2] + v.e[2]);
 }